Eastern boundary upwelling ecosystems integrative and comparative approaches
2-6 June 2008 Las Palmas, Gran Canaria, Spain
Eastern Boundary Upwelling Ecosystems Symposium
Contents Welcome.....................................................................................ii The organisation and sponsors.................................................iii Maps of the local area...............................................................iv Notes for guidance.....................................................................v General programme.................................................................vii Agenda and orders of the day by session................................. 1 Abstracts of the papers and posters by session...................... 37 List of participants.................................................................. 234 Author index.......................................................................... 262
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Eastern Boundary Upwelling Ecosystems Symposium
Welcome We are pleased and honoured to welcome you to the international symposium on Eastern Boundary Upwelling Ecosystems, here in Las Palmas de Gran Canaria. Eastern boundary upwelling ecosystems are uniquely productive systems, providing over a fifth of the marine fish global catch, and significantly contributing to securing livelihood strategies and food in many developing countries. Eastern boundary upwelling ecosystems are driven by intense and episodic winds, and are thus important areas to study the effects of climate on marine processes and on ocean-atmosphere exchanges, topics that are particularly relevant in the context of anthropogenic global warming. This symposium follows on from a number of international meetings that have focused on eastern boundary upwelling ecosystems in the recent past. The major ones are listed here: •
In 1978, the FAO, ICES and the IOC organised here in this city of Las Palmas “The Canary Current: studies of an upwelling system” symposium. This was followed by a series of symposia held in Cape Town, South Africa, under the auspices of the Benguela Ecology Programme (BEP): the “International Symposium on Population and Community Ecology in the Benguela Upwelling Region and Comparable Frontal systems” in 1986, the “Benguela Trophic Functioning Symposium” in 1991 and the “Benguela Dynamics Symposium” in 1996.
•
In 2000, the California and Humboldt Currents systems received the attention of the symposium “Dynamics of Pacific Coastal Upwelling Ecosystems” held in Corvallis, USA.
•
More recently, IRD and IMARPE organised the 2006 “International conference on the Humboldt current system” in Lima, Peru. However, none of these symposia explicitly covered the four main eastern boundary upwelling systems (EBUS), namely the California, Humboldt, Canary and Benguela Currents.
The accumulation of knowledge on the dynamics of EBUS since the 1978 symposium, particularly fuelled by recent technological, methodological and conceptual advances on the functioning of these systems, led us to believe that an integrated and comparative symposium was both possible and timely. Such a symposium would consider most aspects of the dynamics, structure and functioning of the four major eastern boundary upwelling, including climate and ocean dynamics, climate change, physics of the ocean and atmosphere, biogeochemistry, ecosystem production, ecology (including behavioural ecology), food-web structure and dynamics, trophic interactions, and fisheries assessment and management. The idea of the symposium was enthusiastically supported by IRD, the EUR-OCEANS network and IGBP core projects: GLOBEC, IMBER and SOLAS, while ULPGC agreed to provide additional scientific and logistic support. Financial support was further provided by the southern African BENEFIT programme, the German development agency GTZ and the Scientific Committee on Oceanic Research (SCOR). These grants allowed us to fund 26 scientists and students from developing countries, and to partly support 20 keynote speakers. In total the programme includes 142 oral presentations and 170 posters will be on display. We expect an audience of more than 350 people, coming from almost 40 countries from the five continents. The symposium has been structured into plenary and parallel sessions, a trade off to accommodate as many presentations as possible without compromising the objective of addressing integrative and comparative aspects. To further this goal the sessions are not geographically organised, encouraging comparative investigations and multi-disciplinary integration. The vision behind this structure is the recognition that collaboration and cooperation between countries and disciplines is essential if we want to succeed in facing the challenges represented by climate change, sustainability of marine resources and economic globalisation. Thank you for your presence and for your contribution to this endeavour. We trust that you will enjoy this event and we thank the sponsors of this event for making it possible. The convenors Pierre Fréon, Manuel Barange and Javier Arístegui
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Eastern Boundary Upwelling Ecosystems Symposium
The organisation and sponsors Symposium convenors: Pierre Fréon, France Manuel Barange, UK Javier Arístegui, Spain
Scientific Steering Committee
Organisation committee:
Jack Barth, USA
Santiago Hernández-León, Spain (Chair)
Eric D. Barton, Spain
Pierre-François Baisnée, France
Gabriella Bianchi, Italy
Jessica Heard, UK
Bruno Blanke, France
Alonso Hernández-Guerra, Spain
Werner Ekau, Germany
May Gómez, Spain
Véronique Garçon, France
Theodore T. Packard, Spain
Dimitri Gutiérrez, Peru
Magdalena Santana-Casiano, Spain
Salvador Lluch-Cota, Mexico Coleen Moloney, South Africa Vivian Montecino, Chile Abdelatif Orbi, Morocco Cynthia Tynan, USA
Sponsors: The following organisations have kindly sponsored the symposium:
Financial support also gratefully received from:
Local sponsors: Ministerio de Educación y Ciencia Gobierno Autónomo de Canarias Cabildo Insular de Gran Canaria Ayuntamiento de Las Palmas de Gran Canaria vii iii
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Map of the city
Red pin: Auditorium Alfredo Kraus is at "Paseo de Las Canteras s/n", Las Palmas de Gran Canaria, Canary Islands iv ix
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Notes for guidance Registration The symposium secretariat will be based in the hall of the Auditorium Alfredo Kraus. Early registration will take place from 18:00 to 20:00 on Sunday 1 June and from 09:00 to 10:00 on Monday 2 June.
Presentations In order to allow the session to run smoothly and in fairness to other speakers, please note that all presentations are expected to adhere strictly to the time allocated. The time for your presentation can be found in the agendas starting on page 1 of this abstract book. Please give a copy of the electronic file (memory stick, CD, DVD) of your presentation to the symposium secretariat at registration or at least one day before your presentation. The operating system in use is Windows XP (Powerpoint 2003).
Posters The Poster session will take place on Wednesday 4th June from 15:15 to 19:00 in the hall of the Auditorium Alfredo Kraus. Materials to hang posters will be provided and space will be pre-allocated according to the numbering given in this book. Poster presenters are expected to be available to answer questions during the afternoon poster session.
Refreshments There will be morning and afternoon tea/coffee breaks at 09:45 and 17:00 each day. Lunch venues are available close to the Auditorium, at the participant’s expense.
Internet access Free internet access will be available for participants in a room of the Auditorium. Please note there will be no wireless access available during the meeting.
Social activities 1 June:
Welcome reception will commence at 18:00, please register first at the Secretrait, where you will be provided with directions to the reception venue, located near to the Auditorium.
4 June:
Conference reception from 20:00 at the Heineken Marquee. A bus will be provided to transport participants to the venue. This event is co-sponsored. Please get a ticket on registration.
Local tours and sightseeing trips (at participants own expense) can be arranged please ask at the Secretariat for further details.
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Session titles and acronyms Ecosystem Overviews (EO): Ecosystem overview of the major eastern boundary upwelling systems (EBUS) Plenary 1 (PL1): Comparative approaches between eastern boundary upwelling systems (EBUS) & between EBUS and non-EBUS Plenary 2 (PL2): Impacts of climate variability and change on EBU systems Plenary 3 (PL3): Remote and in situ time-series studies: EBUS as ocean observatories for global change Plenary 4 (PL4): Integrated end-to-end food web studies of upwelling ecosystems Plenary 5* (PL5): Resource assessment, management and socio-economic implications of ecosystem based management of EBUS Parallel 1 + Parallel 2** (P1+P2): Physics of the ocean and the atmosphere, and climate change influences on surface ocean-lower atmosphere exchanges Parallel 3 (P3): Coastal - open ocean fluxes and processes Parallel 4 + Parallel 6*** (P4+P6): Biogeochemistry, nutrient cycles and the OMZ, and processes in the sediments and at the sedimentwater interface Parallel 5 (P5): Near shore and estuarine processes related to EBUS Parallel 7 (P7): Phylogenetic, structural and functional diversity of upwelling communities Parallel 8 (P8): Plankton dynamics, food web structure, and ecosystem production Parallel 9 (P9): Small pelagic fishes and the functioning of EBUS Parallel 11 (P11): The role of top predators and their use as ecosystems indicators Parallel 12 (P12): Advances in ecosystem modelling of eastern boundary upwelling systems * Parallel 10 has been merged with PL5, and will be referred to hence forth as PL5 ** Parallel 2 has been merged with Parallel 1 and will be referred to hence forth as P1+P2 *** Parallel 6 has been merged with Parallel 4 and will be referred to hence forth as P4+P6
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Eastern Boundary Upwelling Ecosystems Symposium
General programme
Time
Sessions/Events Early registration
Sunday 1 June
17:00 - 20:00
Monday 2 June
09:00 - 10:00
Registration
10:00 - 11:00
Opening Ceremony (SINFONICA)
11:30 - 12:15
Overview 1 - About the Sponsors (SINFONICA)
12:15 - 13:15
Plenary 2 (SINFONICA)
15:15 - 17:00
Plenary 2 continued (SINFONICA)
17:30 - 19:15
Plenary 4 (SINFONICA)
Tuesday 3 June
Drinks reception
Ecosystem Overview 1 - Canary (SINFONICA)
9:00 - 9:45
Plenary 1 (SINFONICA)
10:15 - 13:30 15:15 - 18:45 Wednesday 4 June
Workshop (GRAN CANARIA)
Parallel 1+Parallel 2** (CAMARA, stage)
Parallel 11 (TENERIFE)
Parallel 12 (GRAN CANRIA)
15:15 - 19:00
Poster Session (Hall of the Auditorium Alfredo Kraus)
20:00
Conference Reception (Heineken Marquee) Ecosystem Overview 3 - California (CAMARA, stage)
9:00 - 9:45
Plenary 3 (CAMARA, stage)
10:15 - 13:30 15:15 - 18:45 Friday 6 June
Parallel 5 (TENERIFE)
Ecosystem Overview 2 - Benguela (CAMARA, stage)
9:00 - 9:45 10:15 - 13:45
Thursday 5 June
Parallel 9 (CAMARA)
Parallel 3 (GRAN CANARIA)
Ecosystem Overview 4 - Humboldt (CAMARA, stage)
9:00 - 9:45
Plenary 5+P10* (CAMARA, stage)
10:15 - 13:00 15:15 -17:00
Parallel 4+Parallel 6*** (TENERIFE)
Parallel 7 (CAMARA) Closing Ceremony (CAMARA)
17:30 - 18:15
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Parallel 8 (CAMARA)
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Agenda and orders of the day by session Ecosystem overview of the major eastern boundary upwelling systems (EBUS).....................................................................................................3
PL1:
Comparative approaches between eastern boundary upwelling systems (EBUS) & between EBUS and non-EBUS..............................................................4
PL2:
Impacts of climate variability and change on EBU systems...................................6
PL3:
Remote and in situ time-series studies: EBUS as ocean observatories for global change..............................................................................................................9
PL4:
Integrated end-to-end food web studies of upwelling ecosystems.......................12
PL5:
Resource assessment, management and socio-economic implications of ecosystem based management of EBUS.............................................................13
P1+P2:
Physics of the ocean and the atmosphere and climate change influences on surface ocean-lower atmosphere exchanges.......................................................15
P3:
Coastal - open ocean fluxes and processes.........................................................18
P4+P6:
Biogeochemistry, nutrient cycles and the OMZ, and processes in the sediments and at the sediment-water interface....................................................20
P5:
Near shore and estuarine processes related to EBUS.........................................23
P7:
Phylogenetic, structural and functional diversity of upwelling communities..........25
P8:
Plankton dynamics, food web structure, and ecosystem production....................26
P9:
Small pelagic fishes and the functioning of EBUS................................................30
P11:
The role of top predators and their use as ecosystems indicators.......................33
P12:
Advances in ecosystem modelling of eastern boundary upwelling systems...........35
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Agenda and orders of the day by session
EO:
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Eastern Boundary Upwelling Ecosystems Symposium
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EO
Ecosystem overview of the major Eastern Boundary Upwelling Systems (EBUS)
Five overviews will be presented at the beginning of every plenary session. The first one is about the activities of the main sponsor of this symposium. The following ones present synthesis of knowledge of each one of the four major eastern boundary upwelling ecosystems. Monday 2 June
Chair: Santiago Hernández-León (Spain) 11:30
J. Arístegui, M. Barange and P. Fréon About the Sponsors
Tuesday 3 June
Chair: Pierre Fréon (France) 09:00
J. Arístegui, X.A. Álvarez-Salgado, E.D. Barton, F. Figueiras, A. Hernández-Guerra, S. Hernández-León, S. Kifani, E. Machu, E. Mason and A. Santos Canary Current upwelling: does geographical diversity make the difference?
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Wednesday 4 June
Chair: Manuel Barange (UK) 09:00
L. Hutchings, C. van der Lingen, L. Shannon, C. Bartholomae, A. van der Plas, D. Louw, A. Kreiner, B. Currie, M. Ostrowski and Q. Fidel The Benguela Current: an ecosystem of four parts, with boundary zones
Chair: Manuel Barange (UK) 09:00
D. Checkley, Jr. Patterns and processes in the California Current system
Friday 6 June
Chair: Pierre Fréon (France) 09:00
V. Montecino and C. Lange Fisheries, ecosystems and paleo-oceanography in the Humboldt Current system
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Agenda and orders of the day by session
Thursday 5 June
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
PL1
Comparative approaches between Eastern Boundary Upwelling Systems (EBUS) & between EBUS and non-EBUS
Tuesday 2 June
Session chairs: Jurgen Alheit (Germany) and Salvador Lluch-Cota (Mexico) Invited speaker: Francisco Chavez (Monterey Bay Aquarium Research Institute, USA) The comparative approach is well adapted to the study of large marine ecosystems such as EBUS, because the four major EBUS display striking similarities but also important differences in their structure, key processes and productivity. They also resemble to/differ from other upwelling systems with eastern or western boundaries. From the interpretation of these similarities and differences one can expect to gain knowledge and better interpretation of the functioning of EBUS.
10:15
F. Chavez and M. Messie A comparative analysis of eastern boundary upwelling ecosystems (PL1 KNS)
10:45
V. Rossi, C. Lopes, J. Sudre, E. Hernandez-Garcia and V. Garçon Spatio-temporal variations of stirring in the surface ocean of the four eastern boundary upwelling systems (PL1 OP1)
11:00
P.T. Strub and C. James Equatorial influences on mid-latitude eastern boundary currents (PL1 OP2)
11:15
G-K. Plattner, N. Gruber, Z. Lachkar, H. Frenzel and D. Loher Ocean carbon cycling and CO2 air-sea exchange in eastern boundary upwelling systems (PL1 OP3)
11:30
Z. Lachkar, N. Gruber, G-K. Plattner, D. Loher and H. Frenzel Biological productivity in eastern boundary current systems (EBCs): a comparative study (PL1 OP4)
11:45
D. Mackas, H. Verheye, P. Ayón, L. Valdés and M. Ohman Comparison of zooplankton time series from four eastern boundary upwelling systems (PL1 OP5)
12:00
C. Lett Simulated patterns of enrichment and retention in the Benguela, northern Humboldt and northern African Canary Current systems (PL1 OP6)
12:15
L. Shannon, Y-J. Shin, M Coll and co-authors Comparing a selection of indicators across upwelling systems for communicating ecosystem states and trends (PL1 OP7)
12:30
P. Fréon, C. Mullon, J. Arístegui, A. Bertrand, R. Crawford, M. Gibbons, L. Hutchings, H. Masski, J. Tam, J. Field, M. Ramdani and D. Checkley Dominant species within functional groups of eastern boundary upwelling ecosytems: what can we learn? (PL1 OP8)
12:45
C. Mullon, P. Verley, D. Dagorne, P-F. Baisnée, X. Capet, F. Colas, P. Penven, P. Marchesiello, J. Tam, S. Neira, C. Moloney, L. Shannon, A. Jarre, K. Watermeier and P. Fréon The Atlas of Eastern Boundary Upwelling Systems (AEBUS): a visualisation tool for the comparison of ecosystems (PL1 OP9)
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13:00
C. Blanchette, E. Wieters and B. Broitman Trophic structure in rocky intertidal communities across the California, Humboldt and Bengula upwelling ecosystems (PL1 OP10)
13:15
Questions
PL1 Posters J. Alheit Synchrony in decadal-scale dynamics of small pelagic fish in Humboldt and Kuroshio Currents
PL1 P2
E.D. Barton, F. Shillington and M. Ostrowski Comparative aspects of the North and South Atlantic upwelling regimes
PL1 P3
X. Capet Submesoscale activity in eastern boundary upwelling systems: underlying processes and impact on the systems’ functioning
PL1 P4
J. Färber Lorda, P. Fiedler and M. Lavín Possible consequences of the oxygen minimum on the day-night differences in zooplankton volume: a comparison between the California Current and the eastern tropical Pacific
PL1 P5
L. Fernández, C. Meiners, A. Ramos, C. Hernández, C. Presas, A. Faraj and M. Ould Bouzouma North west African hakes: a comparison with other hake’s stocks of the EBUS
PL1 P6
E. Klein, I. Chollett, C. Romero and L. Arteaga On the size of upwelling systems
PL1 P7
S. Neira, H. Arancibia and L. Shannon Interaction strength and keystoness in upwelling food webs: comparing the southern Benguela and the southern Humboldt
PL1 P8
K. Nieto and H. Demarcq Role of the mesoscale physical features on the primary production in upwelling areas: comparative approach between Canary and Humboldt systems
PL1 P9
K. Nieto and H. Demarcq A frontal mesoscale index of biological relevance from an automatic detection algorithm of oceanic fronts
PL1 P10
B. Patti, C. Guisande, A.R. Vergara, I. Riveiro, I. Maneiro, A. Barreiro, A. Bonanno, G. Buscaino, A. Cuttitta, G. Basilone and S. Mazzola Factors responsible for the differences in primary production between the four major global upwelling systems: a revisited study using satellite-based net primary production estimates
PL1 P11
L. Soto-Mardones, A. Parés-Sierra, R. Durazo and J.L. Blanco Comparison of seasonal patterns of the eastern Pacific coastal ocean between 22°N-40°N and 22°S-40°S
PL1 P12
A. Trasviña, E.D. Barton, E. González and M.A. Cosío Upwelling in the Gulf of Ulloa, Baja California, Mexico: recent findings and comparisons with other upwelling regions
PL1 P13
R. Venegas, P.T. Strub, R. Letelier and Y. Liu Bio-physical interactions along the four major eastern boundary currents by using a multi-satellite data set between 2002 and 2007
PL1 P14
R. Venegas, R. Letelier and P.T. Strub Spatial and interannual variability in sea surface temperature, chlorophyll concentration, sea surface height, and wind along the four major eastern boundary currents
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Agenda and orders of the day by session
PL1 P1
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
PL2
Impacts of climate variability and change on EBUS
Monday 2 June
Session chairs: X.A. Álvarez Salgado (Spain) and Manuel Barange (UK) Invited speaker: Andy Bakun (Rosenstiel School of Marine and Atmospheric Science, USA) Climate change has already been identified as the cause of significant changes in the physical, biochemical and biological functioning of the oceans. It is also affecting the magnitude and patterns of natural climate variability, and the interactions between atmospheric and ocean climate. This session will focus on describing and estimating the impacts of climate variability and change on the dynamics of either entire EBUS or parts of the ecosystem. 12:15
A. Bakun, D. Field, A. Redondo-Rodriguez and S.J. Weeks Greenhouse gas, ENSO, and potential changes in intensity of coastal upwelling systems (PL2 KNS)
12:45
R. Garreaud and M. Falvey Surface winds along the eastern boundary upwelling systems in future climate scenarios (PL2 OP1)
13:00
K Peard and J-P Roux Changes in the atmospheric forcing of upwelling in the Northern Benguela since 1960: regime changes and long-term trends (PL2 OP2)
15:15
C. Lopes, F. Abrantes and A.C.Miz Diatom transfer functions for sea surface temperature and primary productivity in upwelling areas: The Cupex Project (PL2 OP3)
15:30
X.A. Álvarez–Salgado, U. Labarta, M.J. Fernández–Reiriz, F.G. Figueiras, G. Rosón, S. Piedracoba, R. Filgueira and J.M. Cabanas Coastal upwelling, water renewal rates and the occurrence of harmful microalgae in the Rías Baixas (NW Spain) (PL2 OP4)
15:45
W. Peterson Impacts of climate variability and change on zooplankton dynamics in the coastal upwelling region of the northern California Current (PL2 OP5)
16:00
D. Gutiérrez, A. Sifeddine, I. Bouloubassi, R. Salvatteci, P. Tapia, D. Field, L. Méjanelle, F. Velazco, G. Vargas and L. Ortlieb Upwelling enhancement and pelagic ecosystem responses off Peru since the late nineteenth century (PL2 OP6)
16:15
M. Trudel, D. Mackas and A. Mazumder Prey quality affects the production of wild Pacific salmon in the northern California Current ecosystem (PL2 OP7)
16:30
J-P. Roux, J. Kemper and K. Peard Top predator responses to environmental variability in the northern Benguela: implications for understanding the impact of climate change on the ecosystem (PL2 OP8)
16:45
Questions
6
PL2 posters J. Alves, P. Miranda and N. Serra Climate change impacts on the upwelling off the Western Iberian Peninsula
PL2 P2
S. Banks, D. Ruiz, M. Vera, M. Toscano, N. Tirado, J. Morrison and M. Wolff Galapagos marine communities under strong oceanographic variability – the relevance of applying small scale subsets within large scale regional boundary systems
PL2 P3
A. Bel Madani, A. Chaigneau, V. Echevin, B. Dewitte and D. Correa Connection between mesoscale activity in the Peru-Chile current system and the equatorial Kelvin wave in ROMS (1/6°): 1992-2000
PL2 P4
A. Bode, M.T. Alvarez-Ossorio, J.M. Cabanas, A. Miranda and M. Varela Recent trends in plankton and upwelling intensity off Galicia (NW Spain)
PL2 P5
M.F. Borges, H.Mendes, N.Crato and J. Caiado Modelling stock dynamics of fish productivity in the eastern boundary upwelling ecosystem of Canary/Iberian Peninsula
PL2 P6
J. Boucharel, B. Dewitte, B. Garel, Y. Du Penhoat and C. Bosc Non-Gaussian nature of ENSO signals and climate shifts: implications for regional studies off the western coast of South America
PL2 P7
J. Currie, M. Lucas, L. Hutchings and H. Waldron Long-term nutrient changes in the southern Benguela upwelling region: an indication of climate change?
PL2 P8
B. Dewitte, S. Thual, V. Echevin and S. Purca Impact of the intraseasonal Kelvin wave on the regional circulation of the Humboldt system: the idealised case
PL2 P9
R. Durazo Hydrographic property means and time space variability along the southern extension of the California Current off Baja California, Mexico
PL2 P10
P. Gallegos, E. Ramos, K. Ortega. and J. Tarazona Effects of “El Niño” event 2002-03 on soft-bottom macrobenthos community off the central and south Peruvian coast
PL2 P11
G. Gaxiola-Castro, M. De-la-Cruz and J. Cepeda-Morales Phytoplankton biomass and primary production variability in the California Current off Baja California from 1998 to 2007
PL2 P12
J. Gomez-Valdes and G. Jeronimo Seasonal mixed layer temperature and salinity variability in the tropical boundary of the California Current
PL2 P13
K. Goubanova, V. Echevin, A. Bel Madani, B. Dewitte and A. Chaigneau Using statistical and dynamical downscaling to assess climate change impacts on the Peru-Chile upwelling system
PL2 P14
B. Lavaniegos Influence of persistent low salinity on the zooplankton from the Mexican sector of the California Current
PL2 P15
J. Letelier, H. Reyes, M. Braun and M. Pizarro Oceanographic conditions off northern Chile during La Niña 2007
PL2 P16
J. Marcello, A. Hernández-Guerra, F. Eugenio and A. Fonte Climate change effects over the north west African upwelling ecosystem
PL2 P17
C. Meiners, L. Fernández and A. Ramos Climate variability and upwelling dynamics. Are they linked in NW Africa?
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Agenda and orders of the day by session
PL2 P1
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Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
PL2 P18
M. Moyano, J.M. Rodríguez and S. Hernández-León Ichthyoplankton transport in NW Africa upwelling filaments
PL2 P19
S. Núñez-Ricardo, M. Marchant, D. Hebbeln and C. Lange Increased eddies activity off Northern Chile during the last 500.000 years: deep-sea benthic foraminifer evidences?
PL2 P20
P. Penven, J. Veitch, N. Chang and F.A. Shillington Modelling the inter-annual variations of the Benguela upwelling system
PL2 P21
S. Ribeiro, M. Ellegaard, F. Abrantes and A. Amorim Environmental changes in Western Iberia over the last 200 years as evidenced by marine dinoflagellate cyst records
PL2 P22
D. Roberts, A. Carr and A. Boom Potential for tracking the evolution of the Benguela system along the South African coast using molluscan isotopes
PL2 P23
A. Teles-Machado, Á. Peliz and J. Dubert Study of the Interannual variability of the Iberian and Canary upwelling system
PL2 P24
M. Thiaw, D. Gascuel, D. Jouffre and O. Thiom-Thiaw A surplus production model including the effect of environment: application to the white shrimps stocks in Senegal
PL2 P25
M. Villegas, J. Laudien, W. Sielfeld and W. Arntz Species composition, abundance and spatial distribution of coastal fish and their relation with habitat structure of north Chilean kelp beds
PL2 P26
A. Voelker, E.Salgueiro and L. de Abreu Southward shift of export productivity maxima during glacial cold periods off the Western Iberian Margin
8
PL3
Remote and in situ time-series studies: EBUS as ocean observatories for global change
Thursday 5 June
Session chairs: François Gerlotto (France) and Dimitri Gutierrez (Peru) Invited speaker: Hervé Demarcq (Institut de Recherche pour le Développement, France) The accumulation over the last decades of conventional in situ data and modern data collected by automated in situ or remote sensors allows for the analysis of long term changes in EBUS. Furthermore, paleontological records in the sediments extend the period of study to past centuries and millenniums. Because EBUS are strongly connected to the dynamics and chemical composition of the atmosphere, they are good candidates to track global change and its effects. Given the current interest in setting permanent observatories in a Global Ocean Observation System, this session will assist in identifying what has been and should be monitored in EBUS, and will help to standardise and access global databases.
H. Demarcq Recent trends of primary productivity in upwelling systems in a global warming context (PL3 KNS)
10:45
A. Thomas and P. Brickley Comparisons of chlorophyll interannual variability between the Humboldt and California Current systems (PL3 OP1)
11:00
N.J. Hardman-Mountford, T. Hirata and J. Aiken Seasonal and inter-annual variability in phytoplankton size classes and primary production in eastern boundary upwelling systems (PL3 OP2)
11:15
E.D. Barton and C. Roy Canary Current upwelling: more or less? (PL3 OP3)
11:30
A. Benazzouz, H. Demarcq, K. Hilmi, A. Orbi, A. Atillah, A. Makaoui and J. Larissi Sea Surface Cooling Index derived from satellites images in upwelling areas: the case of the Moroccan coastal upwelling (PL3 OP4)
11:45
M. Ostrowski, P. Chernyshov, I. Gleza, K. Hilmi, S. Kifani, J.O. Krakstad, A. Makaoui, F. Mélin and A. Orbi Evolution of oceanographic conditions in the permanent upwelling region off the northwest Africa 1995-2006, with consequences to distribution of pelagic stocks (PL3 OP5)
12:00
S. Purca, B. Dewitte, B. Giese, J. Vazquez and D. Correa Interannual to decadal variability of SST off the coast of Peru: connection with the equatorial Kelvin wave (PL3 OP6)
12:15
S. Bograd, C. Castro, C. Collins and F. Chavez Long-term trends in spiciness, dissolved oxygen, and inorganic nutrients in the southern California Current system (PL3 OP7)
12:30
S. Lluch-Cota, D. Lluch-Belda, M. Morales-Zárate and H. Herrera-Cervantes Biological action centers as oases within eastern boundary upwelling ecosytems (PL3 OP8)
12:45
A. Sifeddine, D. Gutiérrez, M. Gurgel, M. García, L. Ortlieb, M. Boussafir, F. Velazco, H. Boucher, S. Caquineau and J. Valdés Interdecadal to Centennial variability of paleoproductivity and redox conditions in the Peruvian continental margin during the last two millennia (PL3 OP9)
9
Agenda and orders of the day by session
10:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
13:00
F. Abrantes, C. Lopes and E. Amigoni The last deglaciation paleoproductivity and paleoclimate off Southern Chile: a diatom (accumulation rates, assemblages and transfer functions) view (PL3 OP10)
13:15
Questions
PL3 Posters PL3 P1
J. Agujetas and G. Mitchelson-Jacob The seasonal upwelling and primary production of the Gulf of Panama: ENSO implications
PL3 P2
X.A. Álvarez–Salgado, S. Groom, F. Figueiras, O. Espinoza, J. Otero and B. Taylor Seasonal and interannual variability of satellite–derived net primary and new production in shelf and slope waters of the NW Iberian upwelling system over the period 1998– 2007
PL3 P3
I. Bouloubassi, L. Mejanelle, A. Sifeddine, D. Gutierrez, F. Velazco and L. Ortlieb High resolution biomarker record of upwelling and productivity changes over the last 200 years off central Peru
PL3 P4
D. Dagorne, H. Demarcq and L. Drapeau Satellite Oceanic Observatory Atlas part I: historical data
PL3 P5
D. Dagorne, H. Demarcq and L. Drapeau Satellite Oceanic Observatory Atlas part II: near Real Time data
PL3 P6
B. Fiedler and A. Körtzinger A novel experimental approach for determining CO2 and O2 fluxes in the tropical eastern north Atlantic – experimental setup and preliminary results
PL3 P7
J. Gómez and S. Hernández-León Regimen shift in the Canary Current system
PL3 P8
G. González-Nuevo, E. Nogueira, E. Cabal and E. Álvarez Interannual, seasonal and short-term variability of wind-stress along the NW and N Iberian shelf
PL3 P9
G. King, J. Dias and J. Yang Upwelling index derived from satellite imagery along the West Iberian Coast from 1995-2005
PL3 P10
R. Lemos, M. Juliano and B. Sansó Spatiotemporal variability of four major upwelling systems, 1950-1999
PL3 P11
J. Morales, A.C. Thomas, C. Jimenez, A.J. Mata and L. Marquez Phytoplankton pigment variability in the Northern Canary Current system
PL3 P12
C N Prabhu, T. Rodrigues, J.A. Flores, A.Voelker and F. Abrantes The reconstruction of primary productivity in the Portuguese-margin since the last glacial: Preliminary results from a multi-proxy study
PL3 P13
V. Ramos, J. Pérez-Marrero, O. Llinás, A. Cianca and J. Morales Variation of the Chlorophyll a concentration in the Cape Verde region related to SST, wind and geostrophic currents from satellite data
PL3 P14
P. Rizzo-Aparicio, I. Rodríguez-Ucha, M.J. Santana-Casiano and M. González-Dávila Oxygen and chlorophyll measurements from a Volunteer Observing Ship (VOS) in the eastern South Atlantic Ocean
PL3 P15
D. Rueda Roa, T. Ezer and F. Muller-Karger Characterisation of the Southern Caribbean upwelling system
PL3 P16
E. Salgueiro, P. Martin and F. Abrantes Temperature and productivity calibration along the Southern Portuguese margin, using modern planktonic foraminifera trace element and stable isotope proxies
10
PL3 P17
E. Spyrakos, D. Pérez, Á. Mosquera Giménez, A. Acuña, C. Guisande, Á. GonzálezFernández and J. Torres-Palenzuela Combination of different techniques and methods for the study of water quality and detection of harmful algal events in Ría of Vigo (NW Spain)
PL3 P18
G. Yuras and S. Hormazabal Eastern boundary upwelling systems size variability, 10 years of satellite data
Agenda and orders of the day by session
11
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
PL4
Integrated end-to-end food web studies of upwelling ecosystems
Monday 2 June
Session chairs: Coleen Moloney (South Africa) and Lynne Shannon (South Africa) Invited speakers: Yunne-Jai Shin (IRD, France) Integrating the complexity of a marine ecosystem food web, from primary and secondary production and its forcing factors to top-predators and fisheries, is a challenging task because it requires interaction between and integration of different scales, feedbacks and non-linear processes, as well as prediction of individual behaviour and parameterization. Nonetheless EBUS are good candidates for end-to-end studies because the number of key species and the length of the food web are limited and the processes are reasonably well understood. Several approaches to represent food web will be considered in this session, amongst which functional groups, interaction of individual species, particles with size spectra, individual-based models, etc. 17:30
Y-J. Shin, M. Travers and P. Cury Functional response in a size-based world: a simulation experience in the Benguela ecosystem (PL4 KNS)
18:00
M. Travers, K. Watermeyer, Y-J. Shin and L. Shannon Comparison of two modelling approaches for addressing changes in the food web structure under scenarios of overfishing in the southern Benguela (PL4 OP1)
18:15
J. Jahncke, M. Elliott, B. Saenz, R. Bradley, J. Roth and W. Sydeman Effects of climate variability on ecosystem structure and function in the Gulf of the Farallones, California (PL4 OP2)
18:30
S. Neira, C. Mullon, C. Moloney and P. Cury Mechanisms affecting resilience in an upwelling food web model: the case of the southern Humboldt (PL4 OP3)
18:45
R. Rykaczewski and D. Checkley Influence of ocean winds on the pelagic ecosystem in upwelling regions (PL4 OP4)
19:00
Questions
PL4 Posters PL4 P1
F. Arreguin-Sanchez and S. Martinez-Aguilar The role of the relationship between primary production and monterrey sardine exploited stock on the dynamics of the central Gulf of California ecosystem
PL4 P2
I. Grigorov and O. Aumont An online tool for end-to-end ecosystem model developers: EUR-OCEANS’ Model Shopping Tool (MoST)
PL4 P3
I. Farah Hounaida, N.Charouki and D. Belghyti Study of the diet of the Octopus vulgaris in the Moroccan south Atlantic
PL4 P4
J. Otero, G. DingsØr, G. González Nuevo, N.C. Stenseth and X.A. Álvarez-Salgado Long-term changes in fishery landings from the Canary–Saharan region
PL4 P5
A. Utne Palm, A. Gro Vea Salvanes and B. Currie Sufflogobius bibarbatus - a success species in the Benguela upwelling system due to evolved tolerance of hypoxia and H2S.
12
PL5
Resource assessment, management and socio-economic implications of ecosystem based management of EBUS
Friday 6 June
Session chairs: Max Aguero (Chile) and Gabriella Bianchi (Italy) Invited speaker: Sophie Bertrand (Institut de Recherche pour le Développement, Peru) EBUS provide a wide range of essential goods and services through fisheries, biological diversity, oil, gas and mineral deposits and recreational and commercial opportunities. In addition to economic benefits EBUS provide critical services such as nutrient cycling, flood control, waste treatment, as well as species and genetic refugiae. This has lead to the development of integrated co-management plans with a view to integrate management and conservation objectives under an ecosystem-based management approach. This session will deal with social and economic impacts of these developments in one or more EBUS, as well as traditional economic and bio-economic modelling of EBUS goods and services. The state of fisheries worldwide has raised the need to develop more effective and alternative management strategies and methodologies. These range from the use of innovative platforms for the assessment of fish populations to multi-annual management schemes, novel ways of incorporating risk and uncertainties, implementation of MPAs, stock-recovery plans or participatory management. Particular emphasis will be placed on identifying and developing innovative assessment and management approaches that could be applied across EBUS.
S. Bertrand and E. Díaz Vessel Monitoring Systems: a review of what makes them an innovative platform for ecosystem assessment (PL5 KNS)
10:45
M. Aguero and A. Sanchez-Arcilla A quantitative method for coastal ecosystem performance evaluation under alternative management interventions (PL5 OP1)
11:00
G. Bauleth-D’Almeida and U. Uatjavi The effectiveness of the 200 m depth exclusion zone as a protective measure of spawning and nursery areas of commercially important fish in Namibia (PL5 OP2)
11:15
J. Guitton, A. Sidibe, B. Masumbuko, E. Beibou, M. Soumah, P. Cauquil and P. Chavance A regional information system for improving fisheries governance and assessment, structure and contents (PL5 OP3)
11:30
J. Heymans, U. Sumaila and V. Christensen Exploring policy options and tradeoffs in the northern Benguela ecosystem (PL5 OP4)
11:45
H. Olivera, E. Barriga and C. Salazar Estimation of bioeconomic losses caused by the capture of juvenile Peruvian Hake (Merluccius gayi Peruanus Guilchenot, 1848) for the commercial coastal fleet in the Peruvian sea during 1993-2006 (PL5 OP5)
12:00
C. Kirchner and C. Barttholomae An investigation into spawner-recruitment relationships, including environmental parameters, and the development of reference points for the Namibian sardine (Sardinops sagax) (PL5 OP6)
12:15
R. Oliveros-Ramos and J. Tam Viable control model for management of fisheries: the case of Peruvian hake Merluccius gayi Peruanus (PL5 OP7)
12:30
B. Yannicelli, J. Letelier, J. González, L. Orensanz and A. Parma Mega scale patterns of ‘loco’ catches along the Chilean coast: from coastal oceanography to improved scientific advice for management (PL5 OP8)
13
Agenda and orders of the day by session
10:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
13:00
Questions
PL5 Posters PL5 P1
E. Balguerías, A. Solari and J. Castro Dispersal mechanisms and abundance of Octopus vulgaris in the Cape Blanc up-welling system
PL5 P2
L. Fernández, C. Hernández, A. Faraj, M. Ould Bouzouma and survey teams Deep-demersal fish assemblages in the Canary Current ecosystem
PL5 P3
C. Meiners, L. Fernandez and A. Ramos Fast growth hypothesis of European hake: an alternative approach in NW Africa
PL5 P4
M. Pedraza, C. Gatica, L. Cubillos and E. Navarro Spatial asynchrony in the reproductive condition of the anchovy (Engraulis ringens) associated with the sea surface temperature of the Humboldt Current system between 33° and 40°S
PL5 P5
A. Solari, E. Balguerías, J. Castro, D. Jouffre, C. Bas and M. Thiaw On the dynamics of the common Octopus off Senegal: upwelling as an external forcing
14
P1+P2
Physics of the ocean and the atmosphere, and climate change influences on surface ocean-lower atmosphere exchanges
Wednesday 4 June
Session chairs: Véronique Garçon (France) and Abdelatif Orbi (Morocco) Invited speakers: Eric D. Barton (CSIC, Spain) and Douglas Wallace (IFM-GEOMAR, Germany) EBUS are directly forced by wind. Advances in modelling and observational techniques - both remote sensing and situ - have enhanced our understanding of the spatial and temporal variability of these important regions. Higher definition studies of wind forcing have revealed complex patterns that interact with coastal topography and that are being coupled to increasingly realistic ocean models. Purposeful tracer studies have shed light on vertical exchanges in the ocean, while HF radar has provided unprecedented detail on horizontal patterns of circulation over the continental shelf. Remote sensing techniques at relatively high spatial resolution provide increasingly long and reliable time series to allow comparative studies between EBUS on multi-scaled patterns of variability. This session will include contributions in these and related areas. Climate variability is an important component of the variability in the interaction between the surface ocean and the lower atmosphere in coastal upwelling systems, by influencing a large suite of variables, such as wind forcing, surface ocean stratification, gas solubility and fluxes, and wet and dry depositions of nutrients and contaminants over the oceanic micro-layer. This session will include contributions that relate fluxes and processes at the surface ocean-lower atmosphere interface, with emphasis on the metabolism and feedback effects of the upper ocean micro-layer communities.
E.D. Barton Coastal upwelling: a time-varying view (P1+P2 KNS1)
10:45
D. Wallace Dust in, gases out. Air-sea biogeochemical interactions in the tropical eastern North Atlantic (P1+P2 KNS2)
11:15
M. Batteen, H. Miller and A. Martinho Process-oriented numerical modelling studies of upwelling, currents and eddies in coastal boundary current regions (P1+P2 OP1)
11:30
F. Colas, X. Capet, X. Jin, J. Molemaker, D.B. Chelton and J.C. McWilliams Wind stress and sea surface temperature coupling in eastern boundary upwelling systems (P1+P2 OP2)
11:45
M. Ruiz Villarreal, C. Gonález Pola, R. Sánchez, P. Otero, J. Manuel Cabanas and A. Lavίn The Iberian oleward Current around North and Northwest Iberia (P1+P2 OP3)
12:00
E. Mason, F. Colas, J. Molemaker, A. Shchepetkin, P. Sangrà and J.C. McWilliams Seasonal variability of the Canary Current System (P1+P2 OP4)
12:15
P. Otero, M. Ruiz-Villarreal, P. Conde, M. Cobas, M. Varela, G. González-Nuevo and M. Bernal Observed and modelled spring circulation of the northern limit of the Canary upwelling system during 2007 (P1+P2 OP5)
12:30
V.M. Benitez-Barrios, A. Hernandez-Guerra, J. Pelegri, K.M.M. Lwiza and S. Hernandez-Leon Three-dimensional circulation in the NW African upwelling system (P1+P2 OP6)
15
Agenda and orders of the day by session
10:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
12:45
L. Sørensen, K. Richardson, M.B. Christiansen, J. Nissesn, J. Bendtsen, K.M. Hilligsøe and L. Mouritsen Interaction of physical, chemical and biological processes in atmosphere-ocean CO2 exchange in the Benguela upwelling (P1+P2 OP7)
13:00
L. Renault, D. Boris, E. Vincent and Y. du Penhoat Ocean/Atmosphere regional simulation along the Chilean coasts: sensitivity of the upwelling variability to the spatial resolution of the atmospheric forcing (P1+P2 OP8)
13:15
Questions
P1+P2 Posters P1+P2 P1
H. Bange, A. Freing, S. Gebhardt, A. Kock, A. Körtzinger and T. Steinhoff Long-lived trace gases in the Mauritanian upwelling
P1+P2 P2
J. Boucharel, G. Eldin, Y. Du Penhoat and V. Echevin On the influence of the Galapagos Islands on the Humboldt Current system
P1+P2 P3
A. Chaigneau, G. Eldin and C. Grados Mesoscale dynamics in the north Humboldt Current system - a comparison with the three other upwelling systems
P1+P2 P4
P. Chernyshkov and I. Gleza Interannual modifications in dynamics and shape of boundary between intermediate waters of northern and southern origin in area of the Canary upwelling in 1994-2007, due to ocean level and NAO
P1+P2 P5
L. Crosnier, M. Drévillon and F. Soulat A review of upwelling Indices and implementation in the Mercator-Ocean operational analyses and forecast systems
P1+P2 P6
E. Gutknecht, I. Dadou, G. Charria and V. Garçon Rossby waves interannual variability near the Benguela upwelling system
P1+P2 P7
A. Devis-Morales, R. Montoya and W. Schneider The panama bight upwelling dynamics
P1+P2 P8
D. Donoso, F. Colas and W. Schneider Average circulation and seasonal cycles of hydrographic conditions offshore central Chile by means of ROMS
P1+P2 P9
O. Duteil, Y. Dandonneau, A Lazar and I. Wainer Vertical chlorophyll profile impact on mixed layer temperature and nitrate concentration
P1+P2 P10 F. Echevarría, D. Macías and C. García The Strait of Gibraltar, an upwelling cutting down the upwelling P1+P2 P11
G. Eldin, A. Chaigneau, B. Dewitte, V. Echevin, C. Grados, Y. du Penhoat, L. Renault, L. Vasquez and J. Ledesma Observations of the fine structure of the Peruvian upwelling: preliminary results from the ‘Filamentos’ cruise
P1+P2 P12 M. Glessmer, C. Eden and A. Oschlies Contribution of oxygen minimum zone waters to the coastal upwelling off Mauritania P1+P2 P13 F. Gómez-Valdivia and A. Parés-Sierra Anomalous cooling in the Northern Gulf of California
16
P1+P2 P14 C. Grados, A. Chaigneau, A. Harang, L. Vasquez, J. Ledesma, J. Habasque, B. Dewitte, V. Echevin, G. Eldin and A. Bertrand A regional climatology of the north Humboldt Current system off Peru P1+P2 P15 E. Gutknecht, I. Dadou, V. Garçon and L. Sørensen CO2, O2 and nitrogen loss in the Benguela upwelling system using biogeochemical modelling and in situ data P1+P2 P16 A. Kock, A. Freing, S. Gebhardt and H. Bange Nitrous oxide in the Mauritanian upwelling P1+P2 P17 C. Lathuiliere, V. Echevin, M. Levy and G. Madec Impact of small scale structures on a coastal upwelling ecosystem P1+P2 P18 A. Martínez-Marrero, A. Rodríguez-Santana, A. Hernández-Guerra, E. Fraile-Nuez, F. López-Laatzen, P. Vélez-Belchí and G. Parrilla Water masses, currents and diapycnal mixing in the Cape Verde Frontal Zone P1+P2 P19 I. Montes, C. Böning, F. Colas, J. Tam and W. Schneider Interannual variability of the connection between the equatorial undercurrent and the PeruChile undercurrent during 1999–2004 based on a high-resolution numerical model (ROMS) P1+P2 P20 A-C. Peter and A. Lazar Thermal impact of the coastal waves in the coastal African upwelling areas P1+P2 P21 S. Raimund, P. Morin, M. Vernet, Y. Morel, F. Jourdin and V. Garçon Distribution of volatile halogenated organic compounds in the Iberian Peninsula upwelling system
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P1+P2 P22 G. Rodríguez, L. García-Weil, A. González, J.L. Vega, D. Suarez and J. Coca Spatio-temporal variability patterns, episodic events and coupling effects among remotely sensed sea surface temperature, chlorophyll concentration, dynamic topography and wind fields in the Canary upwelling system
P1+P2 P24 J. Rutlant, P. Paolini and V. Montecino Multiscale analysis of satellite chlorophyll a data around two upwelling foci in Northern Chile P1+P2 P25 J. M. Santana-Casiano, M. González-Dávila and I. R. Ucha Seasonal variability of fCO2 and O2 in the Angola-Benguela region P1+P2 P26 B. Sow, P. Marchesiello and C. Roy The impact of sea-surface temperature on surface winds along Senegalese coasts P1+P2 P27 C Torres, J. Castillo, J. Mueller, C. Trees and M. Stramzka Three-dimensional Circulation in Montery Bay using the General Curvilinear Ocean Model P1+P2 P28 C. Troupin, F. Machín, M. Ouberdous, P. Sangrà and J-M. Beckers Climatology and circulation of the Azores-Canary region by Data-Interpolation Variational Analysis P1+P2 P29 C. Troupin, E. Mason and P. Sangrà Vorticity balance in the northwestern African upwelling
17
Agenda and orders of the day by session
P1+P2 P23 V. Rossi, Y. Morel and V. Garçon Formation of a secondary upwelling front along the shelf break in simplified numerical models and in situ data
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P3
Coastal - open ocean fluxes and processes
Thursday 5 June
Session chairs: Javier Arístegui (Spain) and Bruno Blanke (France) Invited speaker: Jack Barth (Oregon State University, USA) Coastal upwelling ecosystems exchange water and bio-chemical properties with the adjacent boundary currents, through hydrographically complex Coastal Transition Zone (CTZ) regions. In the past two decades, several multidisciplinary studies have addressed the study of physical and biological processes at these highly dynamic boundary regions. However there is still a large lack of knowledge on the mechanisms and magnitude of shelf-ocean exchanges of energy, nutrients and materials, as well as on the impacts of export fluxes to the oceanic domain. This session will highlight the results from recent studies on oceanographic processes at CTZ regions, like fish larvae dispersal by upwelling filaments, or nutrients (including trace metals) and organic matter transport from the shelf to the surface and deep oceanic waters.
15:15
J. Barth Physical processes of shelf-open ocean exchange and their influence on upwelling ecosystems (P3 KNS)
15:45
M. Ruiz Villarreal, R. Sánchez, C. González Pola, A. Bode, A. Calvo-Díaz, C. Rodríguez and A. Lavín An upwelling filament west of Cape Finisterre in August 2005 (P3 OP1)
16:00
J. Dubert, P. Oliveira, Á. Peliz and R. Nolasco Analysis of an upwelling event off Central Portugal: links between physical processes and phytoplankton patterns (P3 OP2)
16:15
J.M. Rodríguez, M. Moyano and S. Hernandez-Leon Fish larvae from the Canaries-Africa coastal transition zone: a review (P3 OP3)
16:30
G. Fischer, G. Karakas, R. Schlitzer, N. Nowald and G. Wefer Particle fluxes and particle transport from the shelf to the open ocean off Cape Blanc, Mauretania: results from observational and modelling studies (P3 OP4)
16:45
C. Morales, L. Torreblanca, P. Hidalgo, S.E. Hormazabal, S. Nuñez, G. Yuras, R. Escribano and A. Sepúlveda Copepod distribution in the coastal transition zone off Concepción, Chile (P3 OP5)
17:30
A. Rubio, B. Blanke, S. Speich and N. Grima Mesoscale eddy activity in the southern Benguela upwelling system from altimetry and model data (P3 OP6)
17:45
J. Veitch, P. Penven and F. Shillington The Benguela: a laboratory for comparative studies of eastern boundary current systems (P3 OP7)
18:00
J. Keister, W. Peterson and S. Pierce Across-shelf advection of carbon and coastal zooplankton species in upwelling filaments of the northern California Current (P3 OP8)
18:15
E. Rienecker, J. Ryan and B. Sackmann Intermediate nepheloid layers in the central California Coastal Zone (P3 OP9)
18
18:30
N. Gruber, T. Nagai, Z. Lachkar, D. Loher, H. Frenzel, J. C. McWilliams and G-K. Plattner On the role of eddies for the transport of organic matter from eastern boundary upwelling regions to the open ocean (P3 OP10)
18:45
B. Blanke, A. Bentamy, X. Capet, N. Chang, F. Colas, B. Dewitte, V. Echevin, N. Grima, E. Machu, P. Marchesiello, P. Penven, C. Roy, S. Speich, J. Veitch And P. Verley Mapping and variability of cross-shore mass transfers in the four major eastern boundary upwelling systems (P3 OP11)
19:00
Questions
P3 Posters
A. Albert, V. Echevin, M. Lévy, O. Aumont and J. Ledesma Impact of Coastal Kelvin waves on the nearshore productivity in the Humboldt Current system
P3 P2
I.J. Alonso-González, J. Arístegui, J.C. Vilas, M. Montero and M. Espino Variability in the water column respiration across the NW Africa-Canary Current Coastal Transition Zone
P3 P3
A. Biccard, G. Branch and M. Pfaff Fast food: the transport of particulate organic matter over an upwelling event on the west coast of southern Africa
P3 P4
N. Chang, P. Penven and F.A. Shillington Modelling the structure and circulation of the Agulhas Bank, South Africa
P3 P5
M. Cornejo, L. Farías and M. Gallegos Oceanic versus coastal contribution of N2O in the upwelling zone off central Chile
P3 P6
A. Cravo, S. Cardeira, M. Madureira and P. Relvas Impact of an upwelling filament off southwest Iberian Peninsula upon the nutrient and chlorophyll a distributions
P3 P7
L. D'Croz and A. O'Dea Coastal upwelling variability in Central America (Panama)
P3 P8
J. Pereira, A. Moreno, S. Lourenço and M. de Fátima Borges Reproduction seasonality in Octopus vulgaris: two versus one breeding peaks under different upwelling regimes
P3 P9
S. Putzeys, C. Almeida, P. Bécognée and S. Hernández-León Carbon fluxes due to diel vertical migrant zooplankton in the transition zone between the North African upwelling and oceanic waters
P3 P10
J. Quispe, C. Torres, O. Morón, N. Dominguez, J. Tenorio and L. Vasquez Hidrodinámica y simulación numérica de la circulación superficial y subsuperficial de las corrientes marinas asociado al sistema de afloramiento costero (11ºS)
P3 P11
V. Rossi, Y. Morel, J. Tassel, F. Jourdin, P. Morin and V. Garçon MOUTON 2007: a field survey of the Iberian Peninsula upwelling system
P3 P12
R. Sánchez, P. Relvas, A. Martinho and P. Miller Physical description of an upwelling filament off southwest Iberian Peninsula
P3 P13
J. Torres Palenzuela, L. Vilas, J. Herrero and E. D. Barton Ocean Color and SST distribution derived from satellite and airborne data in the Ria of Vigo
19
Agenda and orders of the day by session
P3 P1
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P4+P6
Biogeochemistry, nutrient cycles and the OMZ , and processes in the sediments and at the sediment-water interface
Thursday 6 June
Session chairs: Bronwen Currie (Namibia) and Theodore T. Packard (Spain) Invited speakers: Luis Codispoti (HPL/UMES, USA) and Pedro Monteiro (Council for Scientific and Industrial Research, South Africa) Continental margins associated with coastal upwelling regions are thought to play a major role in global biogeochemical cycles. Carbon and nutrient cycles are fuelled by variable inputs of nutrient salts from the open ocean, the continents and the atmosphere. Excess organic matter, not used in the food web, is partly remineralized in both the water column and sediments, although a significant and variable amount remains available for off-shelf transport to the oceanic domain. Enhanced remineralization rates favour the development of Oxygen Minimum Zones (OMZs) in the water column, with strong implications on nutrient cycling, including denitrification, sulphide production and anaerobic ammonium oxidation. This session will focus on the complex biogeochemical interactions in inshore-offshore regions of upwelling ecosystems affected by different levels of hypoxia. This session will include presentations dealing with nutrient cycling, the contribution of dissolved, suspended and sinking organic matter to mineralization processes, the variability in sources and sinks of inorganic nutrients in different upwelling ecosystems, and the differential role of nutrients in limiting primary productivity. The processes in the sediments and at the sediment-water interface are clearly identified as critical components in the study of coastal upwelling biogeochemistry. The role of benthic communities at this boundary layer is however poorly known, due to their complexity and time/space variability. This session will include contributions on the physical, biological and chemical controls of sediment-water exchanges of nutrients, and their influence on food webs and export fluxes, as well as the diagenetic processes that control the balance between deposition, recycling and burial rates in the sediments.
15:15
L. Codispoti Biogeochemical cycling in eastern boundary upwelling systems: large signals from small, temporally variable volumes (P4+P6 KNS1)
15:45
P. Monteiro, A. van der Plas, J-L. Mélice and W.R. Joubert Natural hypoxia variability in upwelling systems: sediment fluxes or physical ventilation? (P4+P6 KNS2)
16:15
C. Castro, F. Alonso-Pérez, B. Arbones and F. Figueiras Seasonal changes of net ecosystem metabolism in the coastal upwelling system of the Ría De Vigo (NW Spain) (P4+P6 OP1)
16:30
B. Currie, K. Peard, V. Brüchert, K-C. Emeis, A.C. Utne Palm, R. Endler, A.G.V. Salvanes and R. Bahlo Living dangerously: implications of hydrogen sulphide for marine life along the Namibian coast (P4+P6 OP2)
16:45
A. Devol and B. Chang Nitrogen gas supersaturation due to denitrification in waters underlying the euphotic zones of eastern boundary upwelling systems (P4+P6 OP3)
17:30
L. Farías, C. Fernández, J. Faundez and M. Cornejo Chemosynthetic processes as carbon source and greenhouse gases (GHG) cycling (N2O and CH4) in central Chile coastal upwelling (P4+P6 OP4)
17:45
P. Hidalgo and R. Escribano Living with the oxygen minimum zone (OMZ) in the Humboldt Current system: the case of Eucalanus inermis (Copepoda-Calanoida) (P4+P6 OP5)
20
18:00
E. Machu, Z. Lachkar, N. Gruber, V. Echevin and J. Arístegui What key factors control phytoplankton spatial variability in upwelling regions? (P4+P6 OP6)
18:15
M. Messié, J. Ledesma, D. Kolber and F. Chavez Nitrate supply and potential primary productivity estimates in four eastern boundary upwelling systems (P4+P6 OP7)
18:30
S.W.A. Naqvi Seasonal upwelling along the west coast of India (P4+P6 OP8)
18:45
T. Packard, D. Blasco, L. Codispoti, M. Estrada, J.C. Christensen, J. Ammerman, P. Coble, R.C. Dugdale, R. Barber, M. Gómez and S. Torres Carbon flux and nitrate uptake in the Peru Upwelling, September 1976 and March 1977: Calculations from enzyme analyses (P4+P6 OP9)
19:00
Questions
P4+P6 Posters E. Enríquez, D. Gutiérrez, L. Quipúzcoa, W. Serrano, D’L. Cuadra, R. Marquina, V. Aramayo and W. Yupanqui Benthic biomass responses to changes of organic matter fluxes induced by ENSO in the Peruvian coastal upwelling ecosystem
P4+P6 P2
C. Fernández, L. Farías, M. Estrella Alcaman and M. Gallegos Nitrogen regeneration in the euphotic zone of the Peruvian upwelling and its contribution to primary production
P4+P6 P3
A. Galan, M. Veronica, T. Bo, W. Dagmar, L. Gaute, K. Marcel and U. Osvaldo Anammox bacteria and the anaerobic oxidation of ammonium in the oxygen minimum zone off northern Chile
P4+P6 P4
M. Gallegos and L. Farías Nitrous oxide (N2O) exchange across the air-sea water interface off North Chile (21ºS – 30ºS) under the influence of the oxygen minimum zone
P4+P6 P5
M. Graco, G. Lavik, G. Flores, L. Jesús, D. Gutiérrez, O. Morón and M. Kuypers Benthic nitrogen cycling associated with the oxygen minimum zone (OMZ) variability of the upwelling Humboldt ecosystem off central Peru
P4+P6 P6
B. Hernández-de la Torre, M. Martínez-Gaxiola, G. Gaxiola-Castro, R. Hernández-Walls and R. Aguirre-Gómez Modelling new primary production (pnew) through temperature-nitrate relationship along Baja California peninsula
P4+P6 P7
A. Makaoui, A. Orbi, K. Hilmi, J. Larissi, I. Benaazouz and S. Zizah Hydrological variability of upwelling areas along the morocccan atlantic coast from 2001 to 2007
P4+P6 P8
H. Naik and W. Naqvi Denitrification in the eastern boundary upwelling zone off India
P4+P6 P9
T. Packard, M. Alcaraz and M. Gómez Exploring measurements of potential respiration
P4+P6 P10 A. Paulmier, D. Ruiz-Pion, I. Masotti and V. Garçon Oxygen Minimum Zones (OMZs): intense reserves of remineralized CO2 close to the surface ocean
21
Agenda and orders of the day by session
P4+P6 P1
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P4+P6 P11
M. Ribas-Ribas, J.M. Hernández-Ayón, V. Camacho-Íbar, A. Mejia-Trejo, A. CabelloPasini and R. Durazo-Arvizu Effects of upwelling, tides and biological factors in the inorganic carbon system in San Quintín Bay, Baja California, Mexico
P4+P6 P12 J.A. Segovia Zavala, F. Delgadillo Hinojosa, M.L. Lares Reyes, A. Tovar Sánchez and S.A. Sañudo Wilhelmy Iron in the upwelling area of California Gulf P4+P6 P13 P. Tapia, F. Velazco, A. Sifeddine, L. Ortlieb and D. Gutiérrez Biogenic, textural and detritic composition of laminated sediments from Lima and Pisco basins, Central Peru
22
P5
Near shore and estuarine processes related to EBUS
Tuesday 2 June
Session chairs: Sergio Navarrete (Chile) and Miguel Santos (Portugal) Invited speaker: George Branch (University of Cape Town, South Africa) Near shore areas (including gulfs, open lagoons and ‘rías’) and estuaries located in EBUS are both influenced by and modify the upwelling process, thus affecting the dynamics of eastern boundary ecosystems. This occurs through direct water mass exchanges between these coastal areas and the continental shelf or indirectly through migration of marine species. The productivity, total biomass and biodiversity are usually high in these areas which often host nurseries of species living on the continental shelf, as well as colonies of marine birds and mammals. During periods of low upwelling intensity, they can be used as refuge areas by some species. The session will focus on processes linking these areas to the overall dynamics of EBUS.
G. Branch The impacts of upwelling on nearshore and intertidal communities in the Benguela upwelling ecosystem (P5 KNS)
15:45
J. Largier Physical and ecological consequences of relaxation in coastal EBUS waters (P5 KNS)
16:00
B. Menge and F. Chan Natural experiments in climate change: impacts of climate variation on coastal food webs (P5 OP1)
16:15
F. Tapia, S. Navarrete, B. Menge, M. Castillo, S. Gaines, J. Largier and J. Castilla Indices for the intensity of upwelling-induced variability in shallow inner-shelf environments (P5 OP2)
16:30
V. Camacho-Ibar, R. Durazo-Arvizu, A. Souza, E. Santamaría-del-Angel, J.M. HernándezAyón, A. Mejía-Trejo, L. Aveytua-Alcázar and E. Ortíz-Campos Upwelling control on nutrient dynamics in San Quintin Bay (Mexico), a hypersaline a coastal lagoon: from short term to interannual variations (P5 OP3)
16:45
R. Kudela, J. Ryan, V. Trainer, G. Pitcher, T. Moita and F. Figueiras Similarities between harmful algal bloom hot spots in eastern boundary current systems: the importance of retention to red tides (P5 OP4)
17:30
M. Cobas-Garcia, M. Ruiz-Villarrea, P. Otero-Tranchero, L. Escalera and B. Reguera Oceanographic conditions affecting the autumn 2005 HAB in North-West Iberia (P5 OP5)
17:45
P. Oliveira, T. Moita and S. Palma Summer diatom and dinoflagellate blooms in Lisbon Bay from 2002 to 2005: pre-conditions inferred from wind and satellite data (P5 OP6)
18:00
B. Broitman, S. Navarrete, C. Blanchette, M. Pfaff, G. Branch and S. Gaines Dynamics of larval arrival to intertidal habitats in California, Chile and South Africa (P5 OP7)
18:15
E. Wieters and S. Navarrete Upwelling-driven variation in algal morphology can propagate through the benthic food webs by shifting the balance of positive and negative interactions (P5 OP8)
23
Agenda and orders of the day by session
15:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
18:30
M. Pfaff, G. Branch, J. Largier and J. Fisher Land ahoy! Different onshore transport mechanisms of mussel and barnacle larvae in the Southern Benguela upwelling system (P5 OP9)
18:45
D. Kaplan, J. Largier, C. Halle and J. Paduan Coastal mesoscale circulation along central California: consequences for larval transport and management (P5 OP10)
19:00
Questions
P5 Posters P5 P1
M. Aguilera-Rodà, A. Eiroa, N. Varo, O. López and L.F. López-Jurado Influences of the tide on the nesting success of Caretta caretta on the Boa Vista Island (Cape Verde, West Africa)
P5 P2
M. Angélico, N. Castro, J. Lino Costa, I. Meneses, C. Nunes, A. Silva, V. Marques, Y. Stratoudakis, P. Oliveira and I. Domingos Coastal fish community structure off Ria de Aveiro, W Iberia, in summer 2007: a potential nursery system
P5 P3
E.D. Barton, R. Torres Almarza, J. Largier, M. Sheridan, A. Trasviña, A. Souza and A. ValleLevinson Influence of the Iberian coastal upwelling and downwelling on the Ria de Vigo, a semi-enclosed bay
P5 P4
M. Fewings, L. Washburn, C. Gotchalk, C. Blanchette and J. Caselle Circulation, water temperature, and larval settlement over the inner continental shelf of the Channel Islands, California
P5 P5
K. Ortega, J. Tarazona and A. Indacochea Distribution patterns of macrobenthos community in sandy beaches of Sechura Bay, Piura, Peru
P5 P6
S. Piedracoba, L. Peteiro, R. Filgueira, X.A. Álvarez-Salgado, G. Rosón, J. Fernández Reiriz and U. Labarta Subtidal and tidal circulation in the Ría de Ares-Betanzos (Iberian upwelling system)
P5 P7
C. Romera Castillo, X.A. Álvarez–Salgado, C. Marrasé and N. Nieto Cid Fluorescence quantum yield of DOM in the coastal upwelling system of the Ría de Vigo (NW Spain): a proxy to microbial and photochemical induced changes in the molecular structure of colored DOM
24
P7
Phylogenetic, structural and functional diversity of upwelling communities
Friday 6 June
Session chairs: Tarsicio Antezana (Chile) and Werner Ekau (Germany) Invited speaker: Josep Gasol (Institut de Ciències del Mar-CMIMA, Spain) Knowledge of biodiversity patterns in the marine environment, and the role of biodiversity in protecting essential ecological processes, is very limited compared to the terrestrial world. This session will consider contributions on all aspects regarding ecological diversity of EBUS, from microbial communities to top predators. This session will include presentations focused on linking diversity to function, and analysing the evolutionary and genetic interrelationships between and within species, as well as structural and functional biodiversity patterns across EBUS, with particular emphasis on the ecological benefits of protecting biodiversity.
J. Gasol, L. Alonso-Sáez, O. Sánchez, D. Vaqué and J. Arístegui Linking microbial diversity and ecosystem function in offshore surface waters affected by upwelling waters: a review of approaches, previous work, and focus on the Canary upwelling waters and the central Atlantic Ocean (P7 KNS)
15:45
D. Ghebrehiwet, J. Field and R. Leslie Exploring the consequence of spatial scale on temporal patterns in diversity: using south coast of South Africa as a case study (P7 OP1)
16:00
C. Brunet, C. Dimier, R. Casotti and F. Conversano Mixed layer and phytoplankton functional diversity: a photobiological approach (P7 OP2)
16:15
T. Antezana Specific patterns of vertical diel migration of euphausiids in the Humboldt Current (P7 OP3)
16:30
Questions
P7 Posters P7 P1
R. Castillo, P. Ayón and Y. Escudero Structural diversity of ostracod assemblages in upwelling regions
P7 P2
A. Ramos, F. Ramil, M. González, S. Soto, E. Soto, E. Balguerías, E. Hernández, C. Meiners, F. Salmerón, E. García, C. Burgos, J.L. Sánz, O. Tello, F.J. Cristobo, A. Faraj and H. Mesfoui Megabenthic biodiversity in continental margins of two main upwelling areas of West Africa
25
Agenda and orders of the day by session
15:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P8
Plankton dynamics, food web structure, and ecosystem production
Thursday 5 June
Session chairs: Philippe Cury (France) and Eric Machu (Morocco) Invited speaker: Coleen Moloney (University of Cape Town, South Africa) The structure of the food web and the interactions between its components has a decisive role in determining the dynamics and productivity of ecosystems. Experimental studies conducted over recent years have helped developed novel and more realistic ecological principles on the structure and dynamics of upwelling food webs, and on the interactions of its components. Presentations will focus on observational and laboratory studies describing and quantifying plankton distribution and productivity, dynamics of food webs in EBUS, with special attention to trophic efficiencies, and global ecosystem production.
15:15
C. Moloney, C. van der Lingen, A. Jarre and L. Shannon Fuelling the food web from phytoplankton to fish (P8 KNS)
15:45
R. Barlow, T. Lamont, B. Mitchell-Innes, D. Louw, M. Kyewalyanga and H. Sessions Primary production in the Benguela ecosystem (P8 OP1)
16:00
J. Huggett, H. Verheye, A. Richardson, L. Hutchings, T. Fairweather, P. Ayon, F. Cazassus, J. Coetzee, R. Escribano, S. Hernández-Leon, A. Kreiner, W. Peterson and S. Zizah Copepod biomass and production in the Southern Benguela – spatio-temporal patterns, links to pelagic fish and comparisons with other eastern boundary upwelling systems (P8 OP2)
16:15
W. Ekau and S. Bröhl Changes in fish larval community of the Northern Benguela upwelling over the last decade induced by changes in the oxygen minimum layer? (P8 OP3)
16:30
L. Postel and A. Da Silva Paradox of upwelling ecosystems? (P8 OP4)
16:45
A. Kreiner and P. Ayón Zooplankton dynamics from 1994 to 2006 in the upwelling systems off Peru and northern Namibia (P8 OP5)
17:30
M. I. Criales-Hernandez, R. Schwamborn, S. Sanchez, P. Ayón, H-J. Hirche and M. Wolff Zooplankton grazing and secondary production off central Peru during recent El Niño and La Niña events (2006 to 2007) (P8 OP6)
17:45
R. Schwamborn, M.I. Criales-Hernandez, P. Ayón, G. Swartzman and H-J. Hirche Zooplankton size spectra in Peruvian marine ecosystems – preliminary results and perspectives for the comparison between large upwelling ecosystems (P8 OP7)
18:00
M. Landry, R. Goericke and M. Ohman Environmental forcing of plankton community trajectories in the California coastal upwelling ecosystem (P8 OP8)
18:15
J. Ryan, R. Kudela, A. Fischer, P. Bissett, S. King, J. Gower and F. Chavez A dinoflagellate red tide incubator in an upwelling shadow: the example of Monterey Bay, California (P8 OP9)
26
18:30
F. Figueiras, B. Arbones and J. Arístegui Phytoplankton and primary production variability along the NW Africa-Canary Islands coastal transition zone (P8 OP10)
18:45
S. Pesant, A. Koslow and A. Waite Coastal waters off Western Australia: an anomalous eastern boundary ecosystem (P8 OP11)
19:00
Questions
P8 Posters V. Anabalón, C. Morales, P. González, O. Pizarro, O. Ulloa, R. Escribano, G. Alarcón and A. Varas Spatio-temporal variation in chlorophyll a, pico- and nanoplankton in the coastal upwelling area off Concepción
P8 P2
H. Auel and W. Ekau Coastal upwelling systems as equatorwards extensions of distribution range for high-latitude pelagic species – a case study on the amphipod T. gaudichaudi in the Benguela Current
P8 P3
M. Ballón Soto, A. Lebourges-Dhaussy, M. Gutierrez, S. Peraltilla and A. Bertrand Acoustic study of the spatiotemporal distribution of zooplankton biomass off Peru provides new insights into Humboldt Current system productivity
P8 P4
F. Baltar, J. Arístegui, M. Montero, M. Espino, M. García-Muñoz, J. Gasol and G. Herndl Seasonal versus mesoscale variability in the abundance, distribution and trophic structure of nano- and picoplankton communities along the NW Africa- Canary Islands transition zone
P8 P5
F. Buchholz New results on Euphausia hanseni as a component of the upwelling systems of the NamibianAngolan shelf under conditions of climatic change
P8 P6
J. Cabal Naves, E. Nogueira, J. Miquel Batle, G. Gonzalez-Nuevo, R. Revilla, E. Alvarez and J. Bueno Accumulation of northern krill (Meganyctiphanes norvegica) in a converge zone at the southern Bay of Biscay.
P8 P7
F. Cazassus, P. Ayón, R. Escribano, J. Huggett, A. Kreiner, H. Verheye and S. Zizah Zooplankton during El Niño-type events in eastern boundary current systems
P8 P8
J. Chen, B. Huang, X. Liu, L. Lin, L. Wang and S. Xu Phytoplankton dynamics related to cyclonic eddies in the South China Sea
P8 P9
J. Cruz, A. dos Santos, J. Pastor and A. Miguel Santos Zooplankton seasonal variation at an upwelling shadow coastal station off Western Iberia: relation to environmental conditions
P8 P10
A. Da Silva, B. Axelsen and L. Postel Food conditions of an important pelagic fish species north and south of the Angolan Benguela Frontal Region
P8 P11
M. Dopolo and C. van der Lingen Reproductive strategy of Cape horse mackerel Trachurus trachurus capensis inferred from ichthyoplankton data collected in the southern Benguela upwelling system, 2000 – 2005
27
Agenda and orders of the day by session
P8 P1
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P8 P12
A. Pérez, R. Escribano, K. Donoso and K. Manríquez Metazooplankton variability at the coastal upwelling zone off central Chile (36°S) in the eastern boundary Humboldt-Current
P8 P13
Y. Escudero, R.Castillo and P. Ayón Vertical distribution and migration of a zooplankton community off Callao in the Humboldt Current in 1996 and 1997
P8 P14
O. Espinoza, B. Crespo, I.G. Teixeira and F. Figueiras Seasonal variability in microbial autotrophic and heterotrophic plankton biomass in the northwestern Iberian shelf
P8 P15
O. Ettahiri, Am. Berraho, A. Ramzi, R. Houssa, A. Orbi and E. Machu Analysing spawning habitats of Sardina Pilchardus Atlantic Moroccon coast (21°N-26°N)
P8 P16
D. Franklin, A. Poulton, J. Young, M. Steinke and G. Malin Phytoplankton community composition, DMSP-lyase and dimethylsulphide (DMS) in the Mauritanian upwelling in June 2006
P8 P17
S. Giglio, O. Pizarro, M. Marchant and H. González Interannual variability of particle fluxes in the eastern South Pacific
P8 P18
M. Gómez, I. Martinez and T. Packard Does ETS activity follow Kleiber’s Law?
P8 P19
M. Gómez, S. Hernández-León, C. Almeida and S. Torres Mesozooplankton biomass and enzymatic metabolic activities increases in the boundaries of island-generated eddies
P8 P20
H. González, G. Daneri, J. Iriarte, E. Menschel, R. Torres, C. Vargas and R. Vera The role of the `biological pump´ in the Humboldt Current system off Chile: the significance of upwelling versus fjord systems
P8 P21
B. Grote, W. Ekau, W. Hagen and H. Verheye Condition of young Cape hakes M. capensis and M. paradoxus in the southern Benguela upwelling system off South Africa
P8 P22
B. Huang, J. Hu, J. Chen and H. Hong Phytoplankton community structure and its response to Chinese subtropical coastal upwelling using diagnostic pigments
P8 P23
J. Iriarte, H. González, G. Daneri, C. Vargas, M. Sobarzo and C. Valenzuela Size-fractionated biomass and productivity of phytoplankton in two areas of the Humboldt Current system off Chile: the role of diatoms in coastal upwelling and fjord systems
P8 P24
A. Kunzmann and F. Buchholz Respiration physiology of fish larvae and krill from the Benguela system
P8 P25
T. Lamont, R. Barlow, M. Kyewalyanga and H. Sessions Phytoplankton photosynthesis in the southern Benguela
P8 P26
J. Landeira, F. Lozano Soldevilla, S. Hernández-León and E.D. Barton Spatial variability of invertebrate larvae around Gran Canaria Island
P8 P27
J. Landeira, F. Lozano Soldevilla, S. Hernández-León and E.D. Barton The influence of upwelling filaments and island-induced eddies on the decapod larvae distribution in the Canaries Coastal Transition Zone
P8 P28
L. Linacre, R. Lara-Lara, M. Hernández-Ayón and M. Landry Microplankton role in the carbon flux of a coastal upwelling area off northern Baja California, Mexico
28
P8 P29
K. Manríquez, R. Escribano and P. Hidalgo The size-structured community of mesozooplankton off Central Chile (36°S) in the eastern boundary Humboldt-Current as assessed by ZooImage analysis
P8 P30
J. Menkel and W. Peterson Temporal and spatial variation in the distribution of adult and juvenile Euphausia pacifica and Thysanoessa spinifera in the Northern California Current for the years 1998 through 2006
P8 P31
C. Schmoker and S. Hernández-Léon Micro and mesozooplankton biomass during the late winter bloom in the Canary Islands waters
P8 P32
C. Shaw, L. Feinberg and W. Peterson Euphausiid population dynamics in the coastal upwelling zone off the Oregon Coast, USA
P8 P33
L. Sobrinho-Gonçalves, M. Moita and M. Cunha Relative distribution of phytoplankton and mesozooplankton in the upwelling system off NW Portugal
P8 P34
I. Teixeira, B. Crespo, S. Piedracoba and F. Figueiras The microbial food web in the coastal upwelling system of the Ría de Vigo (NW Iberia)
P8 P35
M. Wolff, M. Taylor, J. Mendo, J. Tam and C. Yamashiro Comparing the dynamics of the nearshore and the offshore Humboldt Current system trophic webs: the role of fisheries, environmental drivers and trophic relationships
Agenda and orders of the day by session
29
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P9
Small pelagic fishes and the functioning of EBUS
Tuesday 3 June
Session chairs: Arnaud Bertrand (Peru) and Souad Kifani (Morocco) Invited speakers: Carl van der Lingen (Marine and Coastal Management, South Africa) Eastern boundary upwelling ecosystems are all characterised by a high abundance of a reduced number of small pelagic fish species. Because of this, EBUS are often described as wasp-waist ecosystems. The biomass of small pelagic fish can reach several million tons, but it varies considerably at different timescales, as do their horizontal and sometimes vertical distribution. As they are mostly planktivorous and short-lived, small pelagic fish react strongly and quickly to changes in upwelling intensity and location. Nonetheless, the reasons for their large fluctuations in abundance are still debated. Small pelagic fish support large fisheries and a number of top-predators. They play a key role in the interplay between the influence of environmental variables, exploitation and species interactions. Therefore, understanding the ecology and behaviour of small pelagic fish populations is central in the study of the functioning of EBUS.
15:15
C. van der Lingen, J-P. Roux and L. Shannon The role of small pelagic fishes in the functioning of eastern boundary upwelling systems (P9 KNS)
15:45
S. Garrido, R. Rosa, R. Ben-Hamadou, E. Cunha, A. Chícharo and C. van der Lingen Spatio-temporal variability in fatty acid trophic biomarkers in stomach contents and muscle of Iberian sardine (Sardina pilchardus) and its relationship with upwelling and spawning (P9 OP1)
16:00
P. Espinoza, A. Bertrand, C. van der Lingen and B. Rojas de Mendiola Trophic ecology of the sardine Sardinops sagax in the northern Humboldt Current system: filling the gap for a comparison between small pelagic fish from eastern boundary upwelling systems (P9 OP2)
16:15
T. Brochier, F. Colas, V. Echevin, X. Capet, C. Lett, C. Mullon and P. Fréon Small pelagic fish reproductive strategies in upwelling systems: a homing evolutionary model to study environmental constraints (P9 OP3)
16:30
A. Staby, A. Gro Vea Salvanes and A. Fernø Does the behaviour and life history strategy of Maurolicus muelleri reflect local adaptations to environmental conditions? A comparison between the oceanic northern Benguela and fjordic Masfjorden (P9 OP4)
16:45
S. Hernández-León A 9-year periodicity in small pelagic fish recruitment from upwelling areas (P9 OP5)
17:30
R. Rodríguez-Sánchez, C. van der Lingen, M. Manzano, L. Hutchings and H. Villalobos Comparing the influence of oceanographic fronts on interannual changes in the distribution and relative abundance of sardine in the California and Southern Benguela Current systems (P9 OP6)
17:45
M. Barange, J. Coetzee, M. Gutierrez, K. Hill, Y. Oozeki, A. Takasuka, C. van der Lingen and V. Agostini Habitat expansion and contraction in anchovy and sardine populations in EBC and WBC (P9 OP7)
30
18:00
A. Bertrand, A. Chaigneau, J. Coetzee, J. Habasque, L. Hutchings, J. Ledesma, S. Peraltilla and C. van der Lingen Does the vertical extent of suitable physical habitat constrain small pelagic fish populations in the Humboldt and Benguela Current upwelling systems? (P9 OP8)
18:15
O. Moron, M. Ñiquen and J. Alheit Why the Peruvian anchovy collapsed and why it recovered again (P9 OP9)
18:30
J-P. Roux What is driving Cape Hake recruitment in Namibia? How the collapse of small pelagics can affect a demersal stock in a degraded upwelling system (P9 OP10)
18:45
R. Houssa, A. Lakhnigue, A. Marhoum, H.Chfiri, K.Oakka, H.Gourich and H.Elwazzani Fishing effort spatial analysis and its relation to the resources distribution: case of the seiners fleet fishing in the Moroccan Atlantic Sea, between Cap Cantin and Cap Blanc (P9 OP11)
19:00
Questions
P9 Posters M. Aksissou and B. El Yazidi Population dynamics of the anchovy Engraulis encrasicolus around Larache (NW of Morocco)
P9 P2
M. Angélico, M. Bernal, Y. Stratoudakis, P. Beillois, G. Boyra, G. Costas, C. Franco, D. Garabana, L. Ibaibarriaga, M. Iglesias, M. Jiménez, A. Lago de Lanzós, V. Marques, J. Massé, M. Millán, E. Nogueira, C. Nunes, J. Pérez, P. Petitgas, F. Ramos, B. Santos, M. Santos, A. Silva, A. Uriarte and J. Zwolinski ICES - Working Group on Acoustic and Egg Surveys for Sardine and Anchovy (WGACEGG): fish stock estimation and pelagic habitat characterisation in the European North Eastern Atlantic
P9 P3
T. Antezana Feeding modes switches of Trachurus trachurus to respond to heterogeneity of prey size and density
P9 P4
T. Brochier, E. Mason, P. Sangrà and C. Lett Ichthyoplankton transport from the African coast to the Canary Islands: a case study using a high-resolution hydrodynamic model
P9 P5
S.M. Cahuin, L. Cubillos and R. Escribano The recruitment rate in anchoveta (Engraulis ringens) and climatic regimes off Peru.
P9 P6
P. Caldentey, A. Barrera and S. Hernández-León Annual cycle of pelagic fish off Gran Canaria Island
P9 P7
M. Chlaida, O. Ettahiri, S. Planes, H. Jaziri, S. Kifani and S. Ben cherifi Relationship between genetic structure and ichthyologic aspect on Sardina pilchardus populations in the North Western Africa coasts
P9 P8
L. Cubillos, G. Claramunt, K. Riquelme, C. Castillo-Jordán and L. Castro Spawning and daily egg production for common sardine (Strangomera bentincki) and anchovy (Engraulis ringens) off central southern Chile
P9 P9
L. Cubillos, G. Claramunt, C. Castillo-Jordán, R. Serra and M. Braun Spatio-temporal variability in the realised spawning habitat of anchovy (Engraulis ringens) off Northern Chile
31
Agenda and orders of the day by session
P9 P1
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
P9 P10
M. El hafa Growth and reproduction of Engraulis encrasicolus at the bay of Agadir, Morocco
P9 P11
H. El Ouizgani and Y. Snaiki The effect of environmental changes on the recruitment success of Moroccan sardine (Central Atlantic area)
P9 P12
I. Herrera Rivero, A.Barrera Luján and S. Hernández-León Length-weight relationships and reproduction of small and medium pelagic fish species in the Canary Island waters
P9 P13
R. Houssa, S. Kifani and A. Lakhnigue Spatio-temporal variability analysis of two fish stocks: sardine and sardinella in the eastern central Atlantic, from Cape Juby to Cape Blanc
P9 P14
A. Kreiner, E. Stenevik and S. Sundby Synthesis on early life history of pelagic fish species (Sardinops sagax, Engraulis encrasicolus, Trachurus capensis) in the northern Benguela during the early 2000s
P9 P15
J. Letelier, F. Espíndola and M. Braun Ekman transport influence on the spatial distribution of anchovy catch off northern Chile (18º32ºS) during 2006
P9 P16
J. Letelier, J. Cordova, H. Reyes, N. Ramirez and V. Valenzuela Upwelling and upwelling front influence on the spatial distribution of jack mackerel and anchovy off northern of Chile (18º-24ºS)
P9 P17
E. Mohamed Mahmoud, B. Hamady and M. Sidi Cheikh Environment effects on the dynamics of exploitation of the coastal pelagic resources for the North West Africa (between 12° and 26°N)
P9 P18
M. Nevárez Martínez, J. Levenez and J. Santos Molina Nycthemeral behavior of Pacific sardine (Sardinops sagax) and consequences on industrial fishery fleet strategy in the Gulf of California
P9 P19
M. Ñiquen, C.Garcia and C.Peña Biological interactions between anchovies and sardines in Peruvian waters
P9 P20
M. Santamaría, J. González, L. J. López Abellán, A. Barrera and E. Balguerías Substitution of Sardine (Sardina pilchardus) for Round sardinella (Sardinella aurita) in the Canary Islands waters
P9 P21
M. Santamaría, J. González, L.J. López Abellán, A. Barrera, E. Balguerías, M.E. Quintero, J. Díaz Cordero, C. López, C. Presas and V. Duque Maturity and spawning of some small pelagic fishes in the Canary Islands related to SST conditions
P9 P22
B. Tjizoo, C. Van der Lingen, L. Drapeau, C. Moloney and A. Kreiner Characterising and comparing the spawning habitats of sardine and anchovy in the Northern Benguela region
32
P11 The role of top predators and their use as ecosystems indicators Wednesday 4 June
Session chairs: Rob Crawford (South Africa) and Elisa Goya (Peru) Invited speaker: Julia Parrish (University of Washington, USA) Top predators (e.g. large piscivorus fish, sharks, marine birds and mammals) are abundant in EBUS where they play a key role in the trophic web functioning but also in shaping the behaviour of they prey through short and long term processes. They also help prevent the spread of diseases. Furthermore, top predators increasingly support eco-tourism activities. Fisheries and top predators often compete for the same resource and the interaction of these two components of the ecosystem is of primary interest. Recent studies show that top predators abundance, population structure, distribution or individual condition integrate the health of the whole ecosystem and can be used as ecosystem indicators.
J. Parrish Perception vs reality: the importance of top predators in a seasonal upwelling system (P11 KNS)
10:45
L. Alza, G. Swartzman and L. Vásquez Composition and at-sea distribution of the seabird community in the Peruvian Humboldt current system, 1998 – 2006 (P11 OP1)
11:00
M. De Ponte Machado Great white pelican predation on seabirds – an endemic behaviour to the benguela current ecosystem? (P11 OP2)
11:15
S. Bertrand, J.C. Marquez and H. Weimerskirch Fishers and marine birds competing for the same fish: foraging strategies and interactions (P11 OP3)
11:30
D. Grémillet and P. Ryan Behavioural resilience of Benguela avian predators facing global change and their value as ecological indicators (P11 OP4)
11:45
P.J.N. de Bruyn, M.N. Bester, S.P. Kirkman, S. Mecenero and J.P. Roux Spatial and temporal variability in the cephalopod component of the diet of Cape fur seals along the Namibian coast (P11 OP5)
12:00
G. Yataco, J. Márquez and L.Alza Are the changes in the distribution latitudinal of fur seals do influence by the abundance, availability and distribution of Peruvian anchovy or by environment predictability? (P11 OP6)
12:15
R. Crawford, R. Altwegg, T. Fairweather, S. Kirkman and A. Makhado The impact of climate change on land-breeding predators in the Benguela ecosystem and its mitigation (P11 OP7)
12:30
D. Costa, S. Shaffer, M. Weise, C. Kuhn, P. Robinson, S. Simmons, M. Kappes, J. Hassrick Y. Tremblay and W. Henry Variation in the foraging behavior of marine mammals and seabirds in the north eastern Pacific Ocean (P11 OP8)
12:45
E. Goya and R. Crawford Comparing top predators abundances (seabirds and pinnipeds) in the Humboldt and Benguela systems (P11 OP9)
33
Agenda and orders of the day by session
10:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
13:00
F. Arreguin-Sanchez, V.H. Cruz-Escalona, L. Salcido-Guevara, R. Ronzon-Rodriguez, M. Zetina-Rejón, I. Loeza and P. Del Monte-Luna Patterns of response of sharks to global change: an ecosystem based approach (P11 OP10)
13:15
Questions
P11 Posters P11 P1
M. Arias Schreiber and J.C. Márquez Sympatric seals feeding behaviour adaptation to dramatic environmental changes in the Humboldt Current
P11 P2
A. Eiroa, M. Aguilera-Rodà, N. Varo, O. López and L.F. López-Jurado Rate predation on the nesting of Caretta caretta because of the Ocypode cursor in Calheta de Pau beach, Boa Vista Island (Cape Verde rep.)
P11 P3
A. Liria Loza, P. Calabuig Miranda and L.F. López Jurado The Columbus crab (Planes minutus) and loggerhead (Caretta caretta) relationship in the Canary Islands: parasitism or symbiosis?
P11 P4
J.C. Márquez, M. Valverde, C. Barriga and H. Weismerskirch Seabird breeding performance as an indicator of immediate ecosystem changes in a small scale
P11 P5
M. Medina Suárez, S. Jiménez Bordón, A. Liria Loza and L. Lopez Jurado Overturning capacity in newly hatched common turtle (Caretta caretta) in captivity
P11 P6
P. Sabarros, J. Durant, R. Crawford and N.C. Stenseth Seabirds response to a prey distributional change in South Africa
P11 P7
F. van Oordt and L. Alza Inter-annual occurrences of small cetaceans in purse-seine fishery operations in relation to environmental variables, 2001-2003
P11 P8
E. Yáñez, C. Silva and R. Vega Climatic variability and the swordfish fishery in the eastern South Pacific Ocean: hypothesis and a conceptual model
34
P12
Advances in ecosystem modelling of Eastern Boundary Upwelling Systems
Wednesday 4 June
Session chairs: Nicolas Gruber (Switzerland) and Christophe Lett (France) Invited speaker: Shin-ichi Ito (Fisheries Research Agency, Japan) The accumulation of knowledge and the progresses in computer science over the last decades, favoured the development of many different kinds of models aimed first at representing and understanding the functioning of EBUS, and subsequently at forecasting their evolution. The models span from physics to biogeochemistry to population dynamics of fish and top predators. Most of these models are in 2 or 3D and represent the temporal dynamics with time-steps varying from seconds to decades, which is appropriate for these highly dynamic systems. They are often coupled to physical processes and integrate more than one trophic level. Advanced models make use of data assimilation, particularly remote-sensing data, and incorporate feed-back processes and non-linear effects. These models still face some challenges regarding downscaling global forcing models, parameterization, validation and forecasting capabilities. This session will focus on, not only the presentation of numerical and mathematical models, but also original conceptual models and statistical approaches.
S-I. Ito, T. Okunishi, F. Shido, T. Hashioka, M. Aita, K. Rose, M. Kishi, B. Megrey, Y. Yamanaka and F. Werner Modelling multi-trophic level marine ecosystems using the NEMURO family models: scientific potential for eastern boundary current upwelling ecosystems (P12 KNS)
10:45
P. Estrade, P. Marchesiello, A. Colin de Verdiere and C. Roy Cross shelf structure of coastal upwelling : a two dimensional extension of Ekman's theory and a mechanism for inner shelf upwelling shut down (P12 OP1)
11:00
P. Verley, C. Lett, C. Mullon, C. Parada, T. Brochier, P. Penven and B. Blanke Ichthyop: a Lagrangian tool for modelling ichthyoplankton dynamics (P12 OP2)
11:15
E. Aguirre Study of the wind variation effects in the upwelling system along the Peruvian coast through data analysis and numerical modelling (P12 OP3)
11:30
D. Ghebrehiwet, Y. Shin and J. Field Assessing spatial patterns in the size structure and sources of fish mortality for the fish communities in the southern Benguela ecosystem based on an IBM model: a comparison across three periods (P12 OP4)
11:45
G. Karakaş, C. Schäfer-Neth, G. Fischer, P. Marchesiello and R. Schlitzer Simulation of particle aggregation and export in an eastern boundary current system (P12 OP5)
12:00
A. Peña and M. Foreman Modelling summer nutrient and phytoplankton dynamics on the west coast of Vancouver Island (P12 OP6)
12:15
C. Parada, C. Mullon, T. Brochier, S. Soto, L. Castro and C. van der lingen Comparing the contribution of vertical migration to onshore transport of anchovy larvae in different upwelling ecosystems: a modelling study (P12 OP7)
35
Agenda and orders of the day by session
10:15
Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
Agenda and orders of the day by session Agenda and orders of the day by session
Eastern Boundary Upwelling Ecosystems Symposium
12:30
R. Martins, A. Faraj, C. Lett, N. Chang, E. Machu, M. Roberts, C. Moloney and É. Vidal Perspectives of modelling cephalopod larval transport in the southern Africa and Canary Current upwelling systems (P12 OP8)
12:45
Questions
P12 Posters P12 P1
K. Elkalay, K. Khalil, M. Znari and M. Loudiki Modelling of the Moroccan Atlantic coast fisheries
P12 P2
S. Neira, C. Moloney, L. Shannon, A. Jarre, K. Watermeyer and P. Cury Ecosystem-based reference points for fisheries management in upwelling ecosystems
P12 P3
T. Packard and M. Gómez A new conceptual model of zooplankton respiration
P12 P4
E. Yáñez, F. Plaza, J. Carlos Gutiérrez, I. Pulido and N. Rodríguez Forecasting anchovy catches (Engraulis ringens) in northern Chile: non-linear multivariate approach
36
Eastern Boundary Upwelling Ecosystems Symposium
Abstracts of the papers and posters by session EO:
Ecosystem overview of the major eastern boundary upwelling systems (EBUS).....................................................................................................38
PL1:
Comparative approaches between eastern boundary upwelling systems (EBUS) & between EBUS and non-EBUS..............................................................43
PL2:
Impacts of climate variability and change on EBU systems...................................56
PL3:
Remote and in situ time-series studies: EBUS as ocean observatories for global change..............................................................................................................74
PL4:
Integrated end-to-end food web studies of upwelling ecosystems.........................91
PL5:
Resource assessment, management and socio-economic implications of ecosystem based management of EBUS...............................................................97
P1+P2:
Physics of the ocean and the atmosphere, and climate change influences on surface ocean-lower atmosphere exchanges.......................................................106
P3:
Coastal - open ocean fluxes and processes.........................................................127
P4+P6:
Biogeochemistry, nutrient cycles and the OMZ, and processes in the sediments and at the sediment-water interface ................................................141
P5:
Near shore and estuarine processes related to EBUS.........................................155
P7:
Phylogenetic, structural and functional diversity of upwelling communities..........167
P8:
Plankton dynamics, food web structure, and ecosystem production....................171
P9:
Small pelagic fishes and the functioning of EBUS................................................196
P11:
The role of top predators and their use as ecosystems indicators.......................215
P12:
Advances in ecosystem modelling of eastern boundary upwelling systems...........227
37
Eastern Boundary Upwelling Ecosystems Symposium
EO
Synthesis of knowledge of each one of the major Eastern Boundary Upwelling Systems
2 June, 9:00
About the sponsors J. Arístegui1, M. Barange2 and P. Fréon3 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus de Tafira, Facultad de Ciencias del Mar, Las Palmas de Gran Canaria, 35300, Spain. Email:
[email protected] 2 GLOBEC IPO, Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, United Kingdom. Email:
[email protected] 3 IRD, UR097 ECO-UP, CRHMT Centre de Recherche Halieutique Méditerranéenne et Tropicale, Avenue Jean Monnet, BP 171, 34203 Sète, France. Email:
[email protected] 1
The Eastern Boundary Upwelling Ecosystems Symposium: integrative and comparative approaches, is sponsored by, the European network of Excellence EUR-OCEANS, L’Institut de recherche pour le développement (IRD, France), the Universidad de Las Palmas de Gran Canaria (Spain) and the international global change programmes GLOBEC, IMBER and SOLAS. EUR-OCEANS is a Network of Excellence co-funded under the European Commission’s 6th Framework Programme for Research and Technological Development (FP6) designed to achieve lasting integration of European research organisations on global change and pelagic marine ecosystems. It includes 160 Principal Investigators scattered in 66 Member Organisations, located in 25 countries. The overall scientific objective of EUR-OCEANS is to develop models for assessing and forecasting the impacts of climate and anthropogenic forcing on food-web dynamics (structure, functioning, diversity and stability) of pelagic ecosystems in the open ocean. The Joint Programme of Activities of EUR-OCEANS comprises: •
Integrating activities on: networking, data, and model integration
•
Jointly executed research, on: (i) pelagic ecosystems end-to-end, (ii) biogeochemistry, (iii) ecosystem approach to marine resources and (iv) within-system integration
•
Activities to spread excellence, targeted at three different groups: (i) Researchers: training and education ; (ii) Socio-economic users and (iii) European public: public outreach through the Association of Aquaria.
•
Management activities.
•
The EUR-OCEANS office is located at the Institut Universitaire Européen de la Mer (IUEM) in Plouzané, France.
IRD is a French public research institute for development. It was originally founded in 1944 under the name of ORSTOM. The Institute focuses on the relationships between man and the environment in tropical and Mediterranean countries, with a view to contributing to sustainable development. The aims of IRD activities are to respond to the major development challenges of countries from the South. IRD fulfils three main missions: research, training and consultancy; it also collaborates on scientific and technical information in countries from the South. The total staff of IRD is above 2200 people. The institute is articulated around three scientific departments: •
Earth and environment
•
Living resources
•
Societies and health
72 research and service units, including joint research units with universities, perform multi-disciplinary scientific activities. Fourteen of these units are dedicated to marine research, including the following that work in upwelling systems: ACAPPELLA, ECO-UP, ESPACE, LEGOS, LEMAR, LOCEAN, LPO, OSIRIS and PALEOTROPIC. The ECO-UP unit (formerly IDYLE) has been specifically working on eastern boundary upwelling systems since 2001, focusing on the: Benguela, Canary and Humboldt ecosystems. The full title of the unit is self explanatory: “Structure and functioning of exploited upwelling ecosystems: comparative analyses within the framework of an ecosystem approach to fisheries”. 38
Eastern Boundary Upwelling Ecosystems Symposium The Universidad de Las Palmas de Gran Canaria (ULPGC) was founded during the 1989 in the wake of repeated calls from all sectors of Gran Canaria’s society for an independent university on their island. However, the University had an immediate predecessor: the Universidad Politécnica de Las Palmas, which had been founded in 1979; and some of the disciplines imparted at the ULPGC today have been taught on Gran Canaria for more than a century. Initially the University had 19 Centres, some of which had been functioning under different names since the mid nineteenth or early twentieth centuries. At present the ULPGC holds 14 Centers, 37 departments and 8 University Research Centers and Institutes. The ULPGC degrees courses cover all the main areas of knowledge: Humanities, Social and Legal Studies, Health and Natural Sciences and Technical Sciences. The University was evaluated in 2005 by the European University Association (EUA), whose findings indicated that “the progress of the ULPGC has been remarkable”. The University’s main strengths are its facilities, the qualification of the teaching and research staff, the development of Information Technology, in which the ULPGC was “one of the best in Spain”, as well as the implementation of a quality system programme. Among the Doctorate Programs that ULPGC offers, 6 have been awarded with the “Quality Standard of the Spanish National Assessment and Accreditation Agency (ANECA), being one of these the Doctorate Program of “Oceanography”. GLOBEC, Global Ocean Ecosystem Dynamics, is a core project of the International Geosphere-Biosphere Programme, co-sponsored by the Scientific Committee on Oceanic Research and the Intergovernmental Oceanographic Commission of UNESCO. GLOBEC was initiated to understand how global change, in the broadest sense, will affect the abundance, diversity and productivity of marine populations comprising a major component of oceanic ecosystems. GLOBEC has a mandate to run until December 2009. The main goal of GLOBEC is “to advance our understanding of the structure and functioning of the global ocean ecosystem, its major subsystems, and its response to physical forcing so that a capability can be developed to forecast the responses of the marine ecosystem to global change”. GLOBEC has activities in 29 countries, including 10 multi-national and 6 regional programmes: •
GLOBEC-ICES Cod and Climate Change
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GLOBEC-PICES Climate Change and Carrying Capacity
•
Southern Ocean GLOBEC
•
Small Pelagic Fishes and Climate Change
•
Climate Impacts on Oceanic Top Predators
•
Ecosystem Studies of Sub-Arctic Seas
The GLOBEC International office is located at the Plymouth Marine Laboratory, UK. IMBER (Integrated Marine Biochemistry and Ecosystem Research) is the third “marine” core project of the International Geosphere- Biosphere Programme co-sponsored by the Scientific Committee on Oceanic Research (SCOR), focusing on ocean biogeochemical cycles and ecosystems. Its Project Office (IPO) is based in Brest, France. IMBER’s goal is “to investigate the sensitivity of marine biogeochemical cycles and ecosystems to global change, on time scales ranging from years to decades”. IMBER is structured into four themes: •
Theme 1. Interactions between Biogeochemical Cycles and Marine Food Webs
•
Theme 2. Sensitivity to Global Change: how will key marine biogeochemical cycles, ecosystems and their interactions, respond to global change?
•
Theme 3. Feedback to the Earth System: what are the roles of the ocean biogeochemistry and ecosystems in regulating climate?
•
Theme 4. Responses of Society: what are the relationships between marine biogeochemical cycles, ecosystems, and the human system?
SOLAS (Surface Ocean - Lower Atmosphere Study) is also a core project of the International GeosphereBiosphere Programme comprising over 1500 scientists in 23 countries. SOLAS is co-sponsored by the Commission on Atmospheric Chemistry and Global Pollution (ICACGP), the World Climate Research Programme (WCRP) and the Scientific Committee on Oceanic Research (SCOR). SOLAS's primary 39
Eastern Boundary Upwelling Ecosystems Symposium objective is “to achieve quantitative understanding of the key biogeochemical-physical interactions and feedbacks between the ocean and atmosphere, and of how this coupled system affects and is affected by climate and environmental change”. Its domain is focused on processes at the air-sea interface and includes a natural emphasis on the atmospheric and upper-ocean boundary layers. SOLAS is structured into three Focus and three Task teams: •
Focus 1: Biogeochemical Interactions and Feedbacks between Ocean and Atmosphere
•
Focus 2: Exchange Processes at the Air-Sea Interface and the Role of Transport and Transformation in the Atmospheric and Oceanic Boundary Layers
•
Focus 3: Air-Sea Flux of CO2 and Other Long-Lived Radiatively Active Gases
•
'Halogens in the Troposphere (HitT)' Task Team
•
Air-Ice Chemical Interactions (AICI) Task Team
•
Organic Aerosols Task Team
The SOLAS International Office sits at the University of East Anglia, Norwich, UK.
3 June, 9:00 (EO1)
Canary Current upwelling: does geographical diversity make the difference? J. Arístegui1, X.A. Álvarez-Salgado2, E.D. Barton2, F. Figueiras2, A. Hernández-Guerra1, S. HernándezLeón1, S. Kifani3, E. Machu3, E. Mason1 and A. Santos4 1
Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus de Tafira, Facultad de Ciencias del Mar, Las Palmas de Gran Canaria, 35300 Spain. Email:
[email protected]
2
Departamento de Oceanografía, Instituto Investigaciones Marinas, Spain.
3
Institut National de Recherche Halieutique, Morocco.
4
Instituto de Investigaçao das Pescas e do Mar, Portugal.
The Large Marine Ecosystem of the Canary Current (CC) is one of the four major eastern boundary upwelling systems of the world ocean, and thus an area of intensive fisheries activity. The coastline is separated into two distinct areas -the Iberian coast and the NW African coast- at the Strait of Gibraltar, where the Mediterranean Sea and the Atlantic Ocean exchange water. The two areas share similarities in local oceanography, productivity and fisheries, but also exhibit their own particularities. In the northern most Iberian region, the Rías Baixas represent a unique ecosystem, strongly interacting with the coastal upwelling and amplifying its signal. Although seasonality in the Trade wind regime is more pronounced in the northern and southern extremes of the CC, the whole region exhibits high annual productivity and fish population yield. Nevertheless, a large fraction of the productivity is presumably lost to the open ocean. In particular, the NW African shelf between Cape Guir (32 N) and Cape Blanc (21 N) exhibits numerous upwelling filaments. These appear topographically generated in general and those arising south of 28 N result largely from the interplay of the coastal jet with eddies shed downstream the Canaries Archipelago. Filaments facilitate nearshore-offshore exchange of water parcels and properties and a net productivity loss. In recent years, considerable information has been gathered from these coastal ecosystems, and several review papers have been published on plankton biology, biogeochemistry or regional fisheries. Here, we present an updated global review of the CC, covering aspects ranging from hydrography, through biogeochemistry to trophic interactions and fisheries, all of which are affected by processes occurring on distances from mesoscale to large scale and over periods from days to decades. The synthesis will highlight recent major advances in experimental studies, both over the coastal shelf and in the open-ocean transition zone, as well as in modelling exercises. Ongoing numerical models range from large-scale and regional circulation off Iberia and NW Africa to coupled physical-biological models looking at plankton productivity or fish population dynamics. 40
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 9:00 (EO2)
Patterns and Processes in the California Current system D. Checkley, Jr. Scripps Institution of Oceanography, La Jolla, CA 92093-0218, USA. Email:
[email protected]
The California Current System (CCS) is forced by the distribution of atmospheric pressure and associated winds in relation to the west coast of North America. Here, I begin with winds and the coast, progress through physical and biological characteristics of the CCS, and conclude by considering future change. The CCS extends from the North Pacific Current to off Baja California, Mexico, with a major discontinuity at Point Conception. Coastal, wind-driven upwelling results in nutrification and biological production. The California Current is in geostrophic balance and brings low salinity water equatorward. The Jet Stream affects winds and thus upwelling. Offshore, curl-driven upwelling results in a spatially large, productive habitat. Instabilities in the California Current include filaments and eddies, with important implications for both cross-shelf transport and retention. Poleward influence in the CCS is from Kelvin waves of equatorial origin. Dominant modes of variability are the event scale, seasons, interannual, ENSO, decadal, and secular, each with physical and biological manifestations. High surface production results in deep and bottom waters depleted in oxygen and enriched in carbon dioxide. T he distributions of pelagic and benthic taxa, including the plankton, fish, marine mammals, and seabirds are often related to ocean physics. Fishing has depleted demersal stocks less than pelagic stocks, and marine mammals, including whales, are recovering. Krill and squid are poorly known and merit study. Future climate change will differ from past change. Of particular concern are changes in winds, stratification, and ocean chemistry.
4 June, 9:00 (EO3)
The Benguela Current: an ecosystem of four parts, with boundary zones L. Hutchings1, C. van der Lingen1, L. Shannon1, C. Bartholomae2, A. van der Plas2, D. Louw2, A. Kreiner2, B. Currie2, M. Ostrowski3 and Q. Fidel4 Marine and Coastal Management, Private Bag X2, Rogge Bay, Cape Town, Western Cape, 8012, South Africa. Email:
[email protected] National Marine Information and Research Centre, Namibia. 3 Institute of Marine Research, Norway. 4 Instituto Nacional Investigaciones Pesquera, Ihla Luanda, Angola. 1 2
The Benguela system is generally known as one of the four major eastern boundary upwelling systems of the world, together with the Humboldt, Canary and California Current systems, which are driven largely by equatorward wind-induced divergence. Within each of these major regions are a number of subdivisions, generally into northern and southern components, based on bathymetry, coastal orientation, temperatures or wind climatology. There are also ecological and political definitions, which may not necessarily coincide with the physical definitions. The Benguela system is unusual as there are two subtropical or warm temperate boundary regions, off Angola and over the Agulhas Bank, which occur to the north and south of the major winddriven upwelling region, which itself is subdivided at 26oS by the powerful Luderitz upwelling cell. Physical, biogeochemical and biological criteria can be used to describe the characteristics of the core regions, the boundaries and the links between them. Of great interest is where important biological components cross the boundary areas at different stages to complete the life history cycle, transporting nutrients in highly concentrated packages in a manner not determined by hydrodynamic considerations. While the “Bakun triad” of factors responsible for the development of high pelagic fish populations (enrichment, concentration and retention) are an important unifying principle for understanding the compromise implicit in adaptation to upwelling systems, the role of predation has been seriously neglected, as has the variable trophic efficiency of the conversion of the carbon fixed by photosynthesis into fish yield, with the proportion not retained, or held in suspension by living organisms, being advected to the ocean interior or sequestrated as sediments to the continental shelf. 40 to 50 years of observations are now allowing us to discern longer-term cycles and trends and the role global climate change will have in the Benguela in terms of shifting boundaries or weakening or intensifying gradients is being explored through observations and modelling. The interannual and decadal signals are so strong in the Benguela region that longer term trends are difficult to distinguish with any certainty. Intensive resource utilisation and the collapse of several fish stocks occurred in the Benguela region during the 1960’s and 1970’s, with different recovery trajectories in the north and the south, reinforce the concept of subsystems within the Benguela Current. The Angolan subsystem can be described as a subtropical transition zone between the cool temperate winddriven upwelling system and the tropical Atlantic, with low upwelling – favourable winds, well-defined warm and
41
Eastern Boundary Upwelling Ecosystems Symposium cool seasons, intermediate productivity and moderate fisheries which are currently declining. An extensive volume of oxygen-depleted water occurs offshore at depth, which constitutes a source of low-oxygen water that enters Namibia. It is separated from the Namibian subsystem by the Angola-Benguela front, a shallow feature with a dramatic thermal signature, which shifts meridionally several degrees each season and every decade or so warm water penetrates deeply into the cool temperate Namibian system with substantial effects on the fisheries. The northern Benguela or north-Central Namibian shelf is a more typical coastal upwelling system with equatorward winds, cool water, high phytoplankton biomass and moderate to high fish biomass, which is currently in a depleted state. A shift from sardines to horsemackerel occurred during the period 19701990, while demersal fish such as hake have partially recovered from intensive fishing pressure just before independence but which are currently in decline. Oxygen-depleted waters and sulphur eruptions result from the local decay of phytoplankton, in combination with the advection of low oxygen water from Angola. This low oxygen water probably restricts the available habitat for pelagic and demersal fish species. The LuderitzOrange River cone (LUCORC) is an intensive perennial upwelling cell where strong winds, high turbulence and strong offshore transport constitute a partial barrier to epipelagic fish species. In addition upwelling source water alters its hydrographic characteristics, principally in salinity and dissolved oxygen content, across this boundary zone. A long term decline in upwelling favourable winds occurred between 1990 and 2005. The southern Benguela region is characterised by a pulsed, seasonal, wind-driven upwelling and a strong presence offshore of warm water of Agulhas origin. Upwelling persists to Cape Point (34oS) and in late summer as far as Cape Agulhas. High primary productivity characterises the newly upwelled water masses, which merge and join to form a belt of enrichment along the coast, constrained by strong thermal gradients of the front separating warmer offshore waters. Unconsumed plankton blooms sink and decay and form low oxygen water, which peaks in late summer and autumn, where it may adversely affect some resources. The west coast is primarily a nursery ground for several fish species which spawn on the Agulhas Bank or in the southern part of the west coast shelf, where they utilise the alongshore jet currents between the upwelled water and the warm offshore water to transport eggs and larvae to the west coast. The onshore movement of pre-recruits and juveniles from the offshore jet to the inshore waters remains problematic. The Agulhas Bank forms the southern boundary of the Benguela system and it display characteristics of both an upwelling system and a temperate shallow shelf system, with seasonal stratification and mixing, coastal, shelf-edge and dynamic upwelling, moderate productivity and a well oxygenated shelf. The fish community is a mixture of species typical of upwelling systems and a diverse group of benthic, largely endemic, sparids, with some Indo-Pacific affinities and vagrants. Despite moderate primary productivity, a high biomass of fish occupy the Bank during the peak summer upwelling season, with some evidence for tight coupling between trophic levels and high predation rates. A cool ridge of upwelled water, with links to coastal upwelling and the presence of the Agulhas bank, appears to play an important but poorly understood role affecting the distribution and productivity of pelagic fish populations. A recent eastward shift in sardine and anchovy populations was followed by four years of poor recruitment by sardine but successful recruitment of anchovy, indicating changes in the early life history patterns of these two species and ending the simultaneous high biomass of two species which traditionally alternate in dominance.
6 June, 9:00 (EO4)
Fisheries, ecosystems and paleo-oceanography in the Humboldt Current system V. Montecino1 and C. Lange2 1 2
Universidad de Chile, Las Palmeras # 3425, Santiago, Casilla 653, Chile. Email:
[email protected] Universidad de Concepción, Chile.
Chile is one of the major fishing nations in the world, artisanal and industrial fisheries are crucial from a socioeconomic perspective. A minimum of four major fisheries are today of great concern in the Humboldt Current System (HCS), and at least one of them (Jack mackerel) is of regional interest in the Pacific Ocean. TURF systems are also a challenge for small scale fisheries. The Chile-Perucoastal upwelling ecosystems have been recently under continuous studies of circulation, carbon fluxes and biophysical interactions. This session will update and highlight the results from studies on pelagic demersal and benthic fisheries, carbon flux and HCS specific coastal ecosystems. Sedimentary proxies of primary productivity, temperature, oxygenation and denitrification will be also addressed, as well as onshore - offshore and down core reconstructions, aiming at delivering the history of the HCS since the Last Glacial Maximum. Also, new results on the Oxygen Minimum Zone (OMZ) that is under intensive studies for fish scales reconstruction and organic matter degradation will be presented.
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Eastern Boundary Upwelling Ecosystems Symposium
PL1
Comparative approaches between Eastern Boundary Upwelling Systems (EBUS) & between EBUS and non-EBUS
3 June, 10:15 (PL1 KNS)
A comparative analysis of eastern boundary upwelling ecosytems F. Chavez and M. Messie Monterey Bay Aquarium Research Institute, Moss Landing, 7700 Sandholdt Road, CA, USA. Email:
[email protected]
Coastal upwelling ecosystems have attracted the attention of scientists and policy makers for their productive fisheries. It is commonly stated that while they occupy only a small fraction of the global ocean by area they contribute a disproportionately large fraction of global fish production. But not all coastal upwelling ecosystems are made the same. What drives the productive fisheries, what makes them different and how are eastern boundary upwelling ecosystems different from other regions of the world ocean that also produce large quantities of fish, the northeast Pacific off Japan for example? Here we review the basic physical, chemical and biological oceanography of four of the major eastern boundary coastal upwelling ecosystems (Benguela, California, Northwest Africa and Peru) with the objective of describing common features and differences. We include the northeast Pacific off Japan in our comparisons in an effort to highlight differences between eastern boundary upwelling and high latitude, winter mixing driven ecosystems. Seasonal and interannual variations are analysed and discussed.
3 June, 10:45 (PL1 OP1)
Spatio-temporal variations of stirring in the surface ocean of the four eastern boundary upwelling systems V. Rossi1, C. Lopes2, J. Sudre1, E. Hernandez-Garcia2 and V. Garçon1 1 2
LEGOS/CNRS, 14 Avenue Edouard Belin, Toulouse, Midi-Pyrénées , 31400, France. Email:
[email protected] IFISC (CSIC-UIB) Palma de Mallorca, Spain.
Eastern boundary upwelling zones constitute the largest contribution to the world ocean productivity, up to 17% of the global fish catch, thus playing a key biological and socio-economical role. They include the Canary, the Iberian Peninsula and the Benguela on the Atlantic Ocean side and the Peru/Chile upwelling systems in the Pacific Ocean. All four areas are particularly characterised, among other features, by a strong alongshore advection, physical forcing by local and large scale winds, seaward extension beyond the continental shelf of the boundary current and an active biological activity via filaments formation. The intensity of the sub- and mesoscale activity is rather high and it is a major challenge to study the complex chlorophyll spatial distribution in connection with the physical mechanisms. The aim of this work is to make a comparative study of these four upwelling systems, focussing on their mesoscale activity and the interaction between marine surface hydrodynamics and biological processes. The basic inputs to our analysis are satellite data of the marine surface including velocity field and chlorophyll concentration. We quantify horizontal transport processes by the well-known method of the Finite Size Lyapunov Exponents (FSLEs). This tool allows us to sort all four eastern upwelling areas concerning their surface mixing activity and to compare simultaneously their respective scales of temporal variability. The annual cycle appears clearly dominant in the different analysed systems. When investigating links with chlorophyll as a proxy for biological activity in these four upwelling systems, results show that surface horizontal stirring and mixing vary inversely with chlorophyll standing stocks. Moreover, Rossi et al. (submitted, GRL 2008) show that Ekman-transport induced upwelling exhibits a positive correlation with chlorophyll. These two findings are complementary since spatial structure in plankton distributions results from both dynamics of the 3D turbulent medium and of the marine ecosystem. Still much needs to be done to fully understand how plankton distributions are controlled by the interplay between the vertical processes and the intrinsic biological dynamics. However FSLEs lead to a clear clustering of subsystems suggesting that one may use these simple Lagrangian diagnostics as integrated and comparative indices for characterizing horizontal dynamical features in all eastern boundary upwellings. 43
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 11:00 (PL1 OP2)
Equatorial influences on mid-latitude eastern boundary currents P.T. Strub and C. James College of Oceanic and Atmospheric Sciences, Oregon State University, 104 COAS Admin Bldg, Corvallis, Oregon, 97331-5503, USA. Email:
[email protected]
Mid-latitude eastern boundary currents (EBC’s, the California, Humboldt, Canary and Benguela Currents) are often portrayed as locally wind-driven upwelling systems. Given the poleward waveguide created by the continental boundary, “distant forcing” is usually included, in the form of wind-forcing from several hundred kilometers equatorward of a given location, with rare intrusions of signals from the more distant equatorial regions. Here we use the broader picture provided by satellite altimeter sea surface height (SSH) and scatterometer winds to examine the influence of equatorial signals on mid-latitude EBC’s, primarily on seasonal time scales, with some attention to shorter and longer time scales. We expect the Southern Hemisphere EBC’s to be fundamentally different from their Northern Hemisphere counterparts, due to: (1) the more complex geometry of the continental coasts between the equator and mid-latitudes in the Northern Hemisphere; and (2) the presence of the ITCZ in the northeast region of both basins, creating more complex circulation patterns in the tropics north of the equator than to the south. In the Pacific, strong winds through the Central American mountain gaps add an additional complication. As a result, we expect the EBC’s in the Southern Hemisphere to be more directly connected to the equatorial currents and SSH signals. Analyses of the satellite data quantify the relative influence of regional wind stress and wind stress curl, compared to equatorial SSH signals, in controlling the circulation in the mid-latitude EBC’s.
3 June, 11:15 (PL1 OP3)
Ocean carbon cycling and CO2 air-sea exchange in eastern boundary upwelling systems G-K. Plattner1, N. Gruber1, Z. Lachkar1, H. Frenzel2 and D. Loher1 1
Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Switzerland. Email:
[email protected]
2
Institute of Geophysics and Planetary Physics, UCLA, USA.
Eastern boundary current (EBC) upwelling systems are ocean regions of intense biogeochemical transformations and transports. Strong Ekman-driven upwelling of nutrient- and carbon-rich waters tends to lead to CO2 outgassing nearshore and biologically-driven CO2 uptake offshore. Yet, the net air-sea CO2 balance of EBCs remains unknown. High near-shore productivity coupled with filaments and other mesoand submesoscale phenomena cause large heterogeneity in upper ocean carbon fluxes and a substantial lateral export of organic carbon to the open ocean. We address the coastal ocean carbon balance in major EBC upwelling systems of the Atlantic and the Pacific Ocean on the basis of the eddy-resolving, physicalbiogeochemical Regional Ocean Modelling System (ROMS). We are currently investigating these coastal processes in two of the four major EBC systems: the California Current (CalCS) and the Canary Current Systems (CanCS). First results confirm the general onshore-offshore trends in the air-sea fluxes, with substantial spatial and temporal differences due to topography, upwelling strength, and eddy activity. The CalCS is modelled to be a very small source of CO2 to the atmosphere, consistent with a recent data-based estimate by Chavez and Takahashi, while for the CanCS this balance is not clear yet. Regarding offshore transport of organic carbon, the CalCS appears to be stronger than the CanCS. Further analyses of the processes that determine the carbon fluxes and the differences between the two systems will be presented and a preliminary outlook as to what extent our conclusion can be applied to EBC in general will be provided. 44
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 11:30 (PL1 OP4)
Biological productivity in eastern boundary current systems (EBCs): a comparative study Z. Lachkar1, N. Gruber1, G-K. Plattner1, D. Loher1 and H. Frenzel2 Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, CHN E 22, Universitätstrasse 16, ETH Zurich, Zurich, Switzerland. Email:
[email protected] 2 Institute of Geophysics and Planetary Physics, UCLA, USA. 1
Eastern boundary current (EBCs) upwelling systems are among the most productive biological systems in the ocean. Yet, individual EBCs show substantial differences in chlorophyll standing stock and primary production for reasons that remain not fully understood. Through a comparative study of the world’s four major EBCs, i.e. the California, Canary, Benguela and Humboldt Current systems, we explore the leading physical processes and the key environmental factors controlling biological productivity within EBCs. We first investigate similarities and contrasts through a neural network analysis based on self-organizing-maps (SOM). The method is applied to monthly observations over the period 1999-2004, including remotely sensed sea-surface temperature, sea-level anomaly, ocean color from which primary production is computed, wind speed and wind direction, as well as a climatology of mixed layer depth. The elements of the SOM reveal substantial differences between the four EBCs and we identified a continuum of classes of physical conditions favouring or inhibiting biological productivity. Our results suggest that while biological productivity is generally enhanced in coastal upwelling systems due to mainly the alongshore wind-driven Ekman pumping, productivity in EBCs is inhibited by three main factors: (1) a strong eddy activity, (2) a narrow continental shelf, and (3) a deep mixed layer. Yet, in the case of a narrow shelf, deeper mixed layers tend to be associated with higher productivity, a finding that we interpret as being caused by nutrient-limitation dominating over light-limitation. The Canary Current system and the California Current system are found to be the most contrasting of all, not only with regard to their productivity, but also in terms of their physical and environmental key properties. Therefore, we focus our further analysis on these two EBCs through a series of model simulations using the eddy-resolving physical biogeochemical Regional Oceanic Modelling System (ROMS). This model-based comparison is then used to provide a better physical understanding of our previous SOM-based findings as well as to investigate other potentially limiting factors, such as iron.
3 June, 11:45 (PL1 OP5)
Comparison of zooplankton time series from four eastern boundary upwelling systems D. Mackas1, H. Verheye2, P. Ayón3, L. Valdés4 and M. Ohman5 Fisheries and Oceans Canada, Institute of Ocean Sciences, PO Box 6000, Sidney, BC V8L 4B2, Canada. Email:
[email protected] Marine & Coastal Management, South Africa. 3 Instituto del Mar del Peru, Peru. 4 IEO, Gijon, Spain. 5 Scripps Institution of Oceanography, USA. 1 2
The short life span (weeks to a year) of mesozooplankton allows their population size to respond strongly and rapidly to interannual environmental change. This, plus the fact that there is no direct fishery mortality, makes long zooplankton time series a valuable resource for understanding how ocean climate affects ecosystem structure and productivity. SCOR Working Group 125 recently compiled zooplankton time series from a number of regions worldwide, and converted them to time series of log scale annual anomalies of total biomass and abundance within species assemblages. Our collection includes several data sets from the four main eastern boundary upwelling systems: the California Current (3 sub-regions, 28-56 years), the Humboldt Current (3 subregions, 35 years), the Benguela Current (2 sub-regions, 16 and 37 years), and the Canary Current (Iberian coast, 10 years). All of the longer biomass time series show very strong (factor of 10 and larger) low frequency variability at multiple time scales (‘ENSO’, decadal regime, and overall trend). The trend component is positive in the Benguela, but negative in the Humboldt and California Current systems. Decadal variability is spatially coherent within current systems (correlation length scale ~1000 km), but weakly correlated or uncorrelated between hemispheres. Responses to ENSO events are ~synchronous but stronger in the Pacific than in the Atlantic. Log-scale anomalies of individual species and species assemblages are usually larger (by 2-3x) than the anomalies of total biomass, and show evidence of strong poleward displacement of zoogeographic boundaries in time intervals when temperature and stratification anomalies are positive.
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Eastern Boundary Upwelling Ecosystems Symposium
3 June, 12:00 (PL1 OP6)
Simulated patterns of enrichment and retention in the Benguela, northern Humboldt and northern African Canary Current systems C. Lett IRD, Institut des Systèmes Complexes, Ecole Normale Supérieure de Lyon, 46 allée d’Italie, 69364 Lyon Cedex 07, France. Email:
[email protected]
Ichthyop, a Lagrangian tool for modelling ichthyoplankton dynamics, is used to simulate and quantify the processes of enrichment and retention, identified by Bakun (1996) as being important for the survival and recruitment of early life stages of pelagic fish. The method relies on tracking the positions of particles within water velocity fields generated by three-dimensional hydrodynamic models, and then using simple criteria for considering particles as participating to enrichment and/or retention. Putative maps of enrichment and retention indices are constructed, and the seasonal variability in these indices is analysed. New results for the northern Benguela and the northern African Canary Current systems are presented, and compared to previous results obtained for the southern Benguela and the northern Humboldt. The results are discussed in relation to anchovy and sardine eggs and larvae distributions in the regions.
3 June, 12:15 (PL1 OP7)
Comparing a selection of indicators across upwelling systems for communicating ecosystem states and trends L. Shannon1, Y-J. Shin2, M Coll3 and co-authors Marine and Coastal Management, Private Bag X2, Rogge Bay, Cape Town, 8012, South Africa. Email:
[email protected] IRD, Sète, France. 3 Dept. of Biological Sciences, Dalhousie University, Canada. 1 2
A suite of simple, easily understandable and meaningful ecosystem indicators has been selected as a comparable basis for communicating how fisheries exploitation is affecting marine ecosystems across the world. These indicators are represented over time (trends over the last two decades) and as recent snapshots to provide a summary of current ecosystem states. The indicator suite is compared across several upwelling ecosystems and with a selection of other marine ecosystems in which small pelagic fish play central ecological roles. Conclusions from this synthesis are compared to other more detailed comparisons that have been undertaken for some ecosystems using more complex, model-derived indicators, to determine to what extent public-oriented indicators can be a helpful means of disseminating information and categorising ecosystems in terms of fishing effects.
3 June, 12:30 (PL1 OP8)
Dominant species within functional groups of eastern boundary upwelling ecosystems: what can we learn? P. Fréon1, C. Mullon1, J. Arístegui2, A. Bertrand3, R. Crawford4, M. Gibbons5, L. Hutchings4, H. Masski6, J. Tam7, J. Field8, M. Ramdani9 and D. Checkley10 IRD, UR097 ECO-UP, CRHMT Centre de Recherche Halieutique Méditerranéenne et Tropicale. Avenue Jean Monnet, BP 171, 34203 Sète, France. Email:
[email protected] 2 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Islas Canarias, Spain. 3 Institut de Recherche pour le Développement, Peru. 4 Marine and Coastal Management, South Africa. 5 BCB Department, University of the Western Cape, South Africa. 6 Institut National des Ressources Halieutiques, Morocco. 7 Instituto del Mar del Peru, Peru. 8 NOAA Southwest Fisheries Science Center, USA. 9 Institut Scientifique, Université Mohammed V, Morocco. 10 Scripps Institution of Oceanography, USA. 1
The four major eastern boundary upwelling systems (EBUS) of the world display similarities and differences regarding their topography, atmospheric forcing and oceanographic conditions that result in some commonalities and discrepancies in their biodiversity and functioning. The comparative approach is extremely relevant when one works at the scale of ecosystems. It is used here to better understand the differences in productivity, 46
Eastern Boundary Upwelling Ecosystems Symposium offshore extension and functioning of the four EBUS from the species diversity within functional groups. Instead of comparing the full biodiversity of the four EBUS we concentrate on the few dominant species that cumulate at least 80% of the biomass within every functional group of a given ecosystem. Functional groups are mainly defined according to their taxonomy, body size and trophic levels and span from plankton to top predators. Benthic organisms are ignored. The major species of every group are identified within four large subdivisions in each system: two latitudinal subdivisions (North and South sub-systems) and two across shore subdivisions (inshore versus offshore). We propose first appropriate graphical presentations of this diversity across ecosystems and then identify tools for inter EBUS comparisons. Finally the data are interpreted, focusing on the challenging question of the reasons explaining the lack of any obvious relationship between the primary production and the secondary and tertiary production across EBUS. Acknowledgements I wish to thank P. Verley (PREVIMER and IRD, France) for developing Ichthyop, B. Blanke (UBO, France), N. Chang (UCT, South Africa), E. Machu (IRD, France), P. Penven (IRD, France) and J. Veitch (UCT, South Africa) who made their ROMS outputs available, P. Ayón (IMARPE, Peru), O. Ettahiri (INRH, Morocco), P. Fréon (IRD, France) and C. van der Lingen (MCM, South Africa) for their expertise on ichthyoplankton, C. Mullon (IRD, France) and C. Roy (IRD, France) who initiated the work on Lagrangian simulations of enrichment and retention.
3 June, 12:45 (PL1 OP9)
The Atlas of Eastern boundary Upwelling Systems (AEBUS): a visualisation tool for the comparison of ecosystems C. Mullon1, P. Verley1, D. Dagorne2, P-F. Baisnée1, X. Capet3, F. Colas3, P. Penven2, P. Marchesiello3, J. Tam4, S. Neira5, C. Moloney5, L. Shannon6, A. Jarre5, K. Watermeier6 and P. Fréon1 IRD, Unité de Recherche ECO-UP, CRH, Avenue Jean Monnet, 34200, Sète. Email:
[email protected] Centre IRD de Bretagne, France. 3 University of California, Los Angeles, USA. 4 Instituto del Mar del Peru, Peru. 5 University of Cape Town, South Africa. 6 Marine and Coastal Management, South Africa. 1 2
AEBUS is a computerised atlas that has been designed to represent the main features of the dynamics of the four major Eastern boundary upwelling systems (Canary, Humboldt, Benguela & California) and to emphasize their difference. This Atlas consists in a set of maps, charts, graphics, and static or animated maps and charts, each accompanied with a legend and a short comment. These representations provide information from different scientific domains such as physics (e.g. current fields, SST, winds, sea surface elevation,), biogeochemistry (e.g chlorophyll indices), trophic dynamics (e.g. food webs, trophic level), economics (e.g. catches, prices indices). All representations have been specifically designed in order to represent most relevant features of upwelling systems dynamics and the main differences between the four EBS. As a collaborative project, the Atlas capitalized on previous results and involved the work of several multidisciplinary research teams active in upwelling systems. We first remind the constitutive choices of the project: what is it and what is not? How does it differ from other scientific projects collecting ecological data in websites? Then we present the choices made to provide the most accurate and relevant graphical display of quantitative and qualitative information. Then we illustrate the possibilities of AEBUS showing the comparison of hydrodynamic structures (e.g. sea surface elevation, vertical structure of upwellings along transects), or trophic structures (e.g. changes of networks structures from the pristine system to several situations of exploitation) from a collection of coastal systems. We end up with a discussion about the possible uses and futures for what is still a USO (Unidentified Scientific information Object). The underlying philosophy of the project is that scientists dispose of a lot of information about ecosystems. We advocate that the organization of this information should be part of a participative management of ecosystems. Scientists and other stakeholders should agree on several types of representations, and use them to jointly discuss the dynamics of marine ecosystems. Spending time together to seek structural features in recent data could significantly improve the quality of exchanges. Ecosystem representations should not be elaborated exclusively to support final decision making just like mere indicators. In order to become the background of management discussions, they should arouse the interest of scientists and managers alike, and be self-promoting. 47
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 13:00 (PL1 OP10)
Trophic structure in rocky intertidal communities across the California, Humboldt and Bengula upwelling ecosystems C. Blanchette1, E. Wieters2 and B. Broitman3 University of California, Marine Science Institute, Santa Barbara, 93106, USA. Email:
[email protected] Pontificia Universidad Catolica de Chile, Chile. 3 National Center for Ecological Analysis and Synthesis, University of California, USA. 1 2
The California, Humboldt and Benguela upwelling ecosystems represent three of the major eastern boundary upwelling ecosystems in the world. Upwelling ecosystems are highly productive and provide over 40% of the world fisheries catch but represent less than 3% of the world ocean surface. Winds from high-pressure cells located at medium latitudes over the oceans create an uplift to the surface (upwelling) of deep, cold water rich in nutrients over the continental shelf. This upwelling is responsible for a significant increase in primary and secondary production in the coastal zone. Here we compare the biological and trophic structure of rocky intertidal communities in each of these major upwelling regions. We evaluated the influence of oceanographic conditions on these communities by using the long-term mean and standard deviation of satellite-based sea surface temperature. Within each of these major upwelling ecosystems we find evidence for a strong influence of oceanographic conditions on community structure and similarity among sites. Although species differ greatly across these regions, we were able to compare community structure in terms of functional groups (kelps, mussels, barnacles, etc.). We found differences in the functional group structure of these ecosystems to be correlated with temporal variability in SST. We suggest that oceanography may be largely involved in the geographic variability detected in patterns of community structure.
48
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL1 P1
PL1 Posters
Synchrony in decadal-scale dynamics of small pelagic fish in Humboldt and Kuroshio Currents J. Alheit Leibniz Institute for Baltic Sea Research, Seestr. 15, Warnemuende, 18119, Germany. Email:
[email protected]
The long-term dynamics of the Humboldt Current ecosystem are characterised by alternating sardine and anchovy regimes and an associated restructuring of the entire ecosystem from phytoplankton to the top predators. These regime shifts seem to be linked to lasting periods of warm or cold water anomalies related to the approach or retreat of warm subtropical oceanic waters to the coast of Peru and Chile. Phases with mainly negative temperature anomalies parallel anchovy regimes (1950s- about 1970; 1985-up to now), whereas the rather warm period from about 1970-1985 was characterised by sardine dominance. The transition periods (turning points) from one regime to the other were 1969-1971 and 1985-1988. The Kuroshio Current Ecosystem and surrounding waters are similarly characterised by alternating periods of sardines and anchovies. Anchovies and sardines in the waters around Japan have been alternating over the last 100 years on a decadal-scale pattern. The most recent transition periods between the two Kuroshio species were strikingly synchronous to those of their Humboldt cogeners. In contrast to the Humboldt populations, Japanese sardines thrived during cold and anchovies during warm periods. The mechanisms causing these abundance alternations are largely unknown, however, the timing of the changes (turning points) from sardine to anchovy periods and back to sardines can be determined now rather exactly. At the time of these ecosystem shifts substantial changes in physical and biological variables in the waters off the east coast of Japan and in the Humboldt Current ecosystem have been observed. The striking synchronies between the two systems extend to the timing of (i) changes between temperature regimes, (ii) sub-surface processes (thermocline depth, MLD), (iii) anchovy and sardine periods, (iv) zooplankton and (v) other nektonic populations. The question remains: how were the changes in temperature regimes and sub-surface processes in both ecosystems synchronized? Evidence is emerging that these ecosystem shifts are associated with large-scale changes in subsurface processes and basin-scale circulation.
Poster: PL1 P2
Comparative aspects of the North and South Atlantic upwelling regimes E.D. Barton1, F. Shillington2 and M. Ostrowski3 Departamento de Oceanografía, Instituto de Investigaciones Marinas, Eduardo Cabello 6, Vigo 36208, Spain. Email:
[email protected] Department of Oceanography, University of Cape Town, South Africa. 3 Institute of Marine Research, Norway. 1 2
The Iberian and Benguela regions represent the meridional extremes of the upwelling ecosystems of the Atlantic Ocean. Both North and South Atlantic systems are characterised by local wind-driven upwelling, strong alongshore advection, a poleward undercurrent, and high productivity of plankton and pelagic fish. Their boundary currents and biological system in each case extend beyond the continental shelf, and both regions are subject to remote physical forcing by large scale tele-connections. Here some basic physical characteristics of both systems are examined and compared, including the wind stress field and variability, the strength of stratification, the pycnocline depth, the upwelling response time, the mixed layer depth, the relative importance of mixing and Ekman transport. Both systems exhibit heterogeneous structure in the form of eddies, fronts, upwelling filaments and river plumes so that differences within systems may be as great as those between systems. Common features include the upwelling coastal jet and its development into persistent and repeatable filaments extending offshore far beyond the shelf edge. Another is the intermittent interruption of summer upwelling by downwelling episodes and shelf poleward flows with similar consequences in terms of Harmful Algal Blooms in both regions. Over the slope, a possibly permanent subsurface poleward current that surfaces in winter may play an important role in the reproduction and retention of important fish species. We explore these common characteristics, and also significant differences, on the basis of historical data and recent surveys off Iberia, NW Africa, Namibia and South Africa. 49
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL1 P3
Submesoscale activity in eastern boundary upwelling systems: underlying processes and impact on the systems’ functioning X. Capet University of Sao Paulo, Instituto Oceanografico, Programa de Engenharia oceanica – UFRJ, Centro de Tecnologia - Bloco C - Sala 203, Ilha do Fundao, Rio de Janeiro, 21949-900, Brazil. Email:
[email protected]
Subtropical eastern boundary upwelling systems (EBS) have relatively low turbulent activity in comparison to the most active regions of the world ocean (typically the western boundary current regions). This activity is nonetheless believed to play an important role in modulating the generally high primary productivity levels sustained by the leading physical process, i.e. coastal upwelling. Over the last 20 years or so EBS mesoscale activity has drawn the most attention, in large part for its presumed role in the lateral redistribution of tracers and momentum between coastal and offshore ocean. Although there is evidence that this occurs to some extent, the scale of oceanic turbulent motion most relevant for the EBS biological activity may arguably be the submesoscale. Indeed in the range of scales 1-10km (ie, scales somewhat smaller than the first internal deformation radius, yet large enough for rotation to remain important) EBS exhibit ubiquitous upper ocean frontal activity that leads to significant horizontal convergence/divergence, and vertical tracer exchange. In this talk we present recent numerical evidences confirming the statistical importance of submesoscale activity in EBS. The underlying dynamics, potential impact on the ecosystems are also examined. This is mainly done in the context of the California Current System but the genericity of the processes at play allows us to propose a qualitative comparison of the four major EBS’s submesoscale activity.
Poster: PL1 P4
Possible consequences of the oxygen minimum on the day-night differences in zooplankton volume: a comparison between the California current and the eastern tropical pacific J. Färber Lorda1, P. Fiedler2 and M. Lavín1 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), División de Oceanología, Carr. TijuanaEnsenada, Km. 107, Ensenada, Baja California, Mexico. Email:
[email protected] 2 NOAA Fisheries, Southwest Fisheries Science Center, USA. 1
According to our recent results in the eastern tropical Pacific (ETPac), no day-night differences in near surface (0-200 m) zooplankton biomass have been found during summer or winter cruises. Trying to understand these, historical data from the EASTROPAC and other cruises were utilised. An ANOVA comparing night and day zooplankton volumes obtained with a 330 µm mesh net, showed significant differences. Other statistical tests separating season, or bimester, also showed significant differences with a multiple way ANOVA. Even if significant differences were found, probably due to the great variability of the data, large areas of the ETPac show a night/day zooplankton volume ratio close to 1, these are, in general, areas characterised by a shallow oxygen minimum layer (40 -100m), in which oxygen is lower than 1 ml/l, and cover a wide area in the northern hemisphere between 5 to 15° N and around the Costa Rica Dome. A pool of zooplankton volume data from the California Current and the ETPac was plotted. California Current zooplankton volume data from the CalCOFI program, showed significant differences between day and night samples obtained with a 505 µm mesh net. Night/day ratios are lower in the ETPac, and, night/day ratios of 1, or, less than 1, were almost absent in the CalCOFI area. It is hypothesized that zooplankton vertical migration is blocked by the oxygen minimum. These differences in zooplankton vertical migration could be important in the trophic relationships, and could improve the recruitment and growth of commercial fish species, since more carbon will be available during more time for the larval, and adult fish in the area of the ETPac than in the California current, and, thus, it could constitute a trophic advantage for commercial species of the ETPac’s shallow low oxygen area. N/D Carbon ratios were calculated, and, no-significant difference in the Carbon N/D was found between the eastern tropical Pacific and the California Current, however, these ratios were smaller in the ETPac area than in the California Current, and showed a greater standard deviation, showing smaller N/D differences in carbon availability in the ETPac. 50
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL1 P5
Northwest African hakes: a comparison with other hake’s stocks of the EBUS L. Fernández1, C. Meiners1, A. Ramos2, C. Hernández3, C. Presas3, A. Faraj4 and M. Ould Bouzouma5 IEO, Centro Oceanográfico Malaga, Puerto pesquero s/n 29640 Fuengirola, Malaga, Spain: email:
[email protected] IEO, Centro Oceanografico de Vigo, Spain. 3 IEO, Centro Oceanografico de Canarias, Spain. 4 Institut National Recherche Halieutique, Morocco. 5 Institut Mauritanien de la Recherche Oceanographique et des Pêches, Mauritania. 1 2
Off the North-west African coasts, the areas of distribution of the three hake species overlap. European hake (Merluccius merluccius) and the black hakes (M. senegalensis and M. polli) are distributed in the region and they can be located together between 20-25º N, being the case of maximum overlapping of hake species in the world. Usually, the scheme of hake’s distribution in the fisheries of the four major eastern boundary current regions is a pairs of hake species that occupy efficiently the bottom ecological niche with a shallow and deep-water hake, but overlap a considerable part of their geographical and bathymetric ranges. Data from observers in commercial vessels, as well as the scientific surveys in the area were used for an ecological analysis of these species and their resistance to heavy fishing pressure, likely to occur in most of the hake stocks in both Northern and Southern Hemisphere. The efficient occupation of the sea-bottom by two or three species, the bathymetric and latitudinal migratory behavior (in summer to high latitude and inshore and in winter to Equator and offshore), the daily vertical migration for feeding and their great voracity (to rise the surface and to feed on pelagic and mid-water prey), the reproductive strategy (indeterminate batch spawners, with a peak in the spawning season, but it find specimens to spawn all year, that ensure the eggs and larvae survival) and their very probable fast growth may be the main determining factors of the resilience of hake stocks. The intrinsic cannibalisme described by other authors as a selfregulation mechanism of the population dynamic was not observed. The hake species occur in a great variety of ecosystems, but they are characteristic inhabitants of productive upwelling regions where they become the most ecological competitive species thanks to environmental conditions linked to the EBUS.
Poster: PL1 P6
On the size of upwelling systems E. Klein¹, I. Chollett¹,², C. Romero¹ and L. Arteaga¹ Remote Sensing Laboratory, Department of Environmental Studies, Universidad Simón Bolívar, Lab Sensores Remotos Pab 1. USB, Caracas, 1080, Venezuela. Email:
[email protected] 2 Marine Spatial Ecology Laboratory, University of Exeter, United Kingdom. 1
The exact identification of the pattern that characterises an upwelling front and the determination of its edges is a non-trivial problem in a fluid media like the marine water. Estimating the size of the upwelling plume with remote sensing maps (sea surface temperature, SST or chlorophyll, concentration Chla) is usually made by marking all the pixels under or over certain limit-value. This critical value is often selected from field or map observations, and sometimes it carries large amounts of subjectivity. This work proposes an objective methodology for the mapping and quantification of upwelling areas from satellite imagery. A standard method is useful to compare different upwelling regions, or the temporal variation (inter annual or seasonal) of the same area. The method is based on two principal steps: 1. the definition of the threshold value that separates upwelled from surrounding waters, 2. the calculation of the area covered by the plume. In this work, step (1) was solved using piecewise regression to identify the maximum gradient in the SST fields, whereas step (2) was solved using a growing recursive algorithm based on neighborhood rules. The SST threshold value depends on the surrounding waters and it can change from year to year. The area calculation showed higher sensitivity to overestimated thresholds, whereas underestimations incurred lower errors. The inclusion of neighborhood rules effectively reduced the overestimation of areas as it takes into account other oceanographic structures (i.e. tidal fronts or narrow filaments) or image processing errors (i.e. cloud edges). As an example, the algorithm performs well in different well-known east-boundary upwelling regions (Humboldt, Benguela) as well as non-EBU systems (Southern Caribbean Sea). As we expected, the SST threshold values showed a marked dependency on the yearly average temperature of the region. The calculated upwelling areas follow the seasonality described for the regions, and are consistently lower than previous reports. The method allows for inter and intra comparisons of upwelling plumes of different systems. 51
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL1 P7
Interaction strength and keystoness in upwelling food webs: comparing the southern Benguela and the southern Humboldt S. Neira1, H. Arancibia2 and L. Shannon3 1 2 3
Marine Biology Research Centre, University of Cape Town, Rondebosh 7702, Cape Town, South Africa. Email:
[email protected] Universidad de Concepción, Chile. Marine and Coastal Management, South Africa.
Keystone species and/or species that have strong trophic interactions play important roles in food web structure and dynamics. Identify these species is a key point for conservation and management issues. Up to date, identification of keystone and strong interacting species in upwelling ecosystems has been circumscribed to a restricted number of experimental and modelling studies. Therefore, the “keystoness” and the interaction strength in upwelling food webs are still poorly known. In this paper, we use results of published ECOPATH models describing the southern Benguela (off South Africa) and southern Humboldt (off Central Chile) to calculate the trophodynamic indicators Keistoness and interaction strength. The aim is to highlight similarities and differences in terms of the trophic role of the main target and non-target groups in these two highly productive food webs. K and IS are calculated using temporal simulations and network indicators obtained with Ecopath and Ecosim software. The observed values of IS of similar fish species in the southern Benguela and southern Humboldt suggest that hakes species have the highest IS value in both systems. Anchovy, common sardine and horse mackerel have lower IS in the southern Humboldt than in the southern Benguela. Although K distributes similarly in both food webs differences in the K value at the level of similar functional groups are observed. For example the top three groups in the southern Humboldt are euphausiids, sea lion and microzooplankton whereas in the southern Benguela are mesozooplankton, macrozooplankton and chondrichthyans. Target species such as small pelagics, horse mackerel and hakes have intermediate values of K. We end the paper by comparing K and IS in the southern Humboldt and the southern Benguela with those found in other marine food webs and discussing these results in the scope of the ecosystem approach to fisheries.
Poster: PL1 P8
Role of the mesoscale physical features on the primary production in upwelling areas: comparative approach between Canary and Humboldt systems K. Nieto and H. Demarcq IRD, Centre de Recherche Halieutique Mediterraneenne et Tropicale Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected]
The aim of this work is to determine the mesoscale variability in the ocean and their effects on the primary production in the Canary and Humboldt upwelling systems, situated at similar production levels but with different active surfaces and seasonal variability. Several studies showed that mesoscale structures are dynamically complex and have a great influence on biological processes. Therefore, they can play an essential role in the differences of productivity observed between these regions. These upwelling systems are very well described by satellite observation, thanks to complete temporal series of the parameters: sea surface temperature (SST), surface chlorophyll, sea level anomaly and wind field (sensors: AVHRR, SeaWiFS, TOPEX / Poseidon and SeaWinds). We apply advanced imaging technologies for the detection of oceanic mesoscale structures and we characterise these structures automatically, to quantify their occurrence and their impact on primary production. A combination of the Canny Edge Detector and Cayulla & Cornillon algorithm were implemented using the Interactive Data Language (IDL). In order to synthesis and transfer the results obtained into quantified information, we propose the creation of a mesoscale gridded front index at a weekly scale, as a combination of the frontal frequency, weighted by the intensity of gradient. The frontal distance is computed as the position of the most persistent fronts in a weekly period. The results obtained on the Chilean Humboldt upwelling system, allow a comparison between the northern and southern regions and show that most of the northern region is dominated by mesoscale structures originated from a persistent upwelling, generating fronts, plumes and filaments. In this region, the extension of the highly productive coastal area is close to the frontal distance and both strongly covary in space. For most of the central-south zone the importance of kinetic energy indicates the presence of eddies, resulting of baroclinic instability of coastal currents. This probably explains the pronounced offshore extension of primary production.
52
Eastern Boundary Upwelling Ecosystems Symposium Despite low values of front index, the frontal activity is situated offshore. The information on upwelling fronts, plumes and filaments visible from SST images are well detected using our improved Cayula & Cornillon algorithm, but eddies are very rarely detected from SST fields. An indicator of mesoscale eddy activity based on altimetry data could be developed to further explore the mechanisms involved in chlorophyll distribution in this region.
Poster: PL1 P9
A frontal mesoscale index of biological relevance from an automatic detection algorithm of oceanic fronts K. Nieto and H. Demarcq IRD, Centre de Recherche Halieutique Mediterraneenne et Tropicale Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected]
Upwelling fronts are a very common feature of the west coasts of the continents subjected to the major upwelling systems; Benguela, California, Canary and Humboldt. Coastal upwelling fronts occur between the cold, nearshore water and the warmer offshore water. These fronts undergo instability that creates other mesoscale structures such as meanders, filaments and eddies. Among the data available to assess front structures, remote sensing data offers the advantage of providing synoptic observations of surface parameters, such as sea surface temperature (SST), chlorophyll a and sea level anomalies. Given the huge volume of satellite data available for oceanic studies, an automatic image processing system is necessary. Some methods have been developed to detect mesoscale front structures, mainly based on the detection of horizontal gradients computed from convolution operators, or boundaries between different water masses. The Cayula & Cornillion method has been the most widely and successfully applied in oceanography, mainly from SST fields. The Cayula & Cornillon method is a regionally based algorithm. A SST satellite image is divided into several windows, each window is then processed independently to evaluate the probability of an edge being present in that window, from a statistical analysis of the SST histogram. Edge pixels are then partially linked so that they form more continuous contours. We propose a major improvement of the algorithm, without any major change in the computing scheme, with an important increase in the detection and the continuity of the fronts. Using a time series of seven years (1473 images at 1km resolution), we observe an average increase of 160 % in the edge detection pixels and an increase of 30 % in the average length of the segment. On the other hand, studying the relationships between physical and biological mesoscale processes requires specifics tools and a spatio-temporal approach to explain the role of the mesoscale structures in the functioning of the lowest links of the food web in the ocean. Quantifying the mesoscale activity of the ocean is a way of synthesising the physical processes of biological relevance, and allows comparison of different ecosystems. We propose a new index of frontal activity, at a weekly scale, by combining our improved edge detection results with the gradient intensity detected by the standard Canny algorithm. The results offer a dynamic view of upwelling ecosystems, and can be combined with various ecosystem indicators and generic tools to study the role of the physical environment and production processes in upwelling systems.
Poster: PL1 P10
Factors responsible for the differences in primary production between the four major global upwelling systems: a revisited study using satellite-based net primary production estimates B. Patti1, C. Guisande1, A.R. Vergara2, I. Riveiro2, I. Maneiro2, A. Barreiro2, A. Bonanno1, G. Buscaino1, A. Cuttitta1, G. Basilone1 and S. Mazzola1 Istituto per l’Ambiente Marino Costiero, Consiglio Nazionale delle Ricerche (IAMC-CNR), Via Luigi Vaccara, 61, 91026 Mazara del Vallo, Italy. Email:
[email protected] 2 Facultad de Ciencias, Universidad de Vigo, Spain. 1
The aim of this study was to further investigate the environmental factors responsible for the differences in satellite-based net primary production (NPP) estimates, expressed in mg C/m2/day, between the California, Canary, Humboldt and Benguela upwelling areas, starting from the results of a previous study based on chlorophyll concentration (Chl a). NPP data used here were generated using the standard algorithm for the Vertically Generalized Production Model (VGPM), a "chlorophyll-based" model that estimates net 53
Eastern Boundary Upwelling Ecosystems Symposium primary production from chlorophyll using a temperature-dependent description of chlorophyll-specific photosynthetic efficiency. The analysis of climatologic values of NPP confirmed higher values in the Benguela system than in the other areas. Upwelling intensity, higher in the Benguela and Humboldt regions, appeared to be able to drive NPP. Specifically, differences in offshore Ekman transport partly explained the lower NPP values in Canary and California and the higher NPP values observed in Benguela and PeruHumboldt. A linear regression model including the fraction of sea surface over the shelf in each 1°x1° box, nitrate, and variability of offshore Ekman transport explained over the 75% of the variance in NPP among the areas. Results seem to confirm the importance of the extension of the continental shelf in the primary production processes.
Poster: PL1 P11
Comparison of seasonal patterns of the eastern Pacific coastal ocean between 22°N40°N and 22°S-40°S L. Soto-Mardones1, A. Parés-Sierra2, R. Durazo3 and J.L. Blanco4 Universidad del Bio-Bio, Casilla 5-C, Concepción-Chile. Email:
[email protected] Centro de Investigación Científica y de Educación Superior de Ensenada, Mexico. 3 Universidad Autónoma de Baja California, Facultad de Ciencias Marinas, Mexico. 4 Center for Coastal Physical Oceanography, Virginia, USA. 1 2
This work reviews the differences and similarities that exist between the upper layer properties and circulation of the California Current (CC) system and the Humboldt Current (HC). The characterisation of both systems is discussed in terms of the mechanisms that modulate them, i.e, solar energy, wind forcing and coast orientation. We used hydrographic and satellite products available for both the CC and HC. Data showed that for both regions between the latitudinal range of 22°- 40°, wind favors upwelling all year long. Latitudinal asymmetry was observed in the maximum of wind forcing. Alongshore transects of temperature distribution shows that asymmetries observed are restricted to the upper 100 m, being the CC region more influenced by local factors such as the presence of the Gulf of California and the proximity of the thermal equator. The salinity distribution, especially the asymmetry observed in the distribution of the subsurface relative salinity minimum, acts as a good parameter that sketches Arctic and sub-Antarctic water mass intrusions. Derived geostrophic currents depict a seasonal behaviour. For the upper 300 m, currents flow towards lower latitudes in both the CC and HC. Both are more intense in summer when there are more gyres and meanders. Changes in coastline orientation favor meanders and gyres by inducing perturbations to the mean flow. Poleward flows also show seasonality and generally are more intense during summer. The counter-current is stronger in the HC, apparently associated to the steepness of the shelf break and the restricted shelf. The most dynamic regions (more meanders, upwelling) are associated with a combination of coastal topography, coastline orientation and wind stress. It was found that irregularities along the coastline are usually coincident with points of higher kinetic energy.
Poster: PL1 P12
Upwelling in the Gulf of Ulloa, Baja California, Mexico: recent findings and comparisons with other upwelling regions A. Trasviña1, E.D. Barton3, E. González2 and M.A. Cosío2 Departamento de Oceanografía Física, CICESE, Unidad La Paz. Miraflores #334 e/ Mulegé y La Paz, Fracc. Bella Vista, La Paz, B.C.S. 23050, Mexico. Email:
[email protected] 2 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Unidad La Paz. Mexico. 3 Departamento de Oceanografía, Instituto Investigaciones Marinas, Spain. 1
The Gulf of Ulloa in the west coast of Baja California is one of the few shelf seas of the Mexican Pacific, and one of the more productive upwelling regions in Mexico. The high-productivity regime develops every spring-summer but it is modulated by intense inter-annual variation. We use several years of satellitederived sea surface temperatures, 10+ years of altimetry-derived geostrophic currents and the historical hydrographic and drifter data base to describe the main features of the circulation. The California Current is an important seasonal influence that approaches the coast every winter-spring season to modify the coastal circulation and the composition of the coastal waters. A seasonal poleward coastal flow also 54
Eastern Boundary Upwelling Ecosystems Symposium exerts significant influence on both seasonal and inter-annual time scales. During ENSO 1997-1998 a poleward coastal current flooded the Gulf of Ulloa with warm tropical waters beyond the normal season. Evidence of previous occurrences is found in the historical data. A productivity model incorporating results from a dynamic model show how the seasonal poleward flow modulates the productivity of the coastal ocean. Extreme events contribute to dramatic losses in productivity. The local fisheries industry reported economic losses of 70+ million dollars after the 1997-1998 ENSO. A comparison with upwelling zones at similar latitudes in the North Atlantic Ocean highlights a number of significant morphological and dynamic features.
Poster: PL1 P13
Bio-physical interactions along the four major eastern boundary currents by using a multi-satellite data set between 2002 and 2007 R. Venegas1, P.T. Strub1, R. Letelier1 and Y. Liu2 1 2
Oregon State University, 104 Ocean Admin Bldg, Corvallis, Oregon, 97330, USA. Email:
[email protected] School of Oceanography, University of Washington, USA.
We will present satellite data showing the bio-physical interactions along the four major Eastern Boundary Currents (EBC), for the six year period (2002 – 2007). Coincident composites of Sea Surface Temperature (SST), Chlorophyll pigment concentration (CHL), Sea Surface Height (SSH) and Wind Stress (TAU) are used for the period between July 4 of 2002 and December 18 of 2007. The seasonal, interannual and nonseasonal variability along each boundary are extracted by using a Self-organizing map (SOM).
Poster: PL1 P 14
Spatial and interannual variability in sea surface temperature, chlorophyll concentration, sea surface height, and wind along the four major eastern boundary currents R. Venegas, R. Letelier and P.T. Strub Oregon State University, 104 Ocean Admin Bldg, Corvallis, Oregon, 97330, USA. Email:
[email protected]
We determine and compare the relationship among spatial patterns of temporal and seasonal means and variability between bio-physical parameters along each EBC. Nearly six years (2002 – 2007) of satellitederived data along the four major Eastern Boundary Currents (EBC) are analysed. Available and coincident 7-days composites of Sea Surface Temperature (SST) and Chlorophyll pigment concentration (CHL) from MODIS-Aqua, Sea Surface Height (SSH) and Sea Level Anomalies (SLA) from AVISO, and Wind Speed and derived Wind Stress from QuikSCAT are used. Along shore time series at inshore and offshore locations highlight the local variability in each EBC.
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Eastern Boundary Upwelling Ecosystems Symposium
PL2
Impacts of climate variability and change on EBU Systems
2 June, 12:15 (PL2 KNS)
Greenhouse gas, ENSO, and potential changes in intensity of coastal upwelling systems A. Bakun1, D. Field2, A. Redondo-Rodriguez3 and S.J. Weeks3 Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA. Email:
[email protected] 2 Monterey Bay Aquarium Research Institute, USA. 3 Centre for Marine Studies, University of Queensland, Australia. 1
The Pacific ENSO system acts to rearrange global water vapor distributions in more or less repeatable and well-understood ways. Since water vapor is the most important of the atmospheric greenhouse gases, ENSO variability presents an opportunity to investigate certain potential effects of enhanced anthropogenic greenhouse gas concentrations (i.e., “climate change”) on a multiple-realization empirical basis, rather than being forced to rely on the illusory statistical reliability of a mere secular trend line. This is particularly important in projecting effects on wind-driven upwelling systems, since an evident artifact in the historical maritime wind reports data base may impart an artificial overall increasing trend in wind speeds. Here we use this ‘ENSO-determined water vapor variability’ approach to address greenhouse gas effects on coastal upwelling systems, using the particularly ENSO-affected Peru system as an example. It is well established that on ENSO time scales, the upwelling-favorable wind off Peru varies in opposite phase to the Pacific trade wind circulation, in spite of the fact that the former flows directly into the latter (i.e., local wind-induced upwelling strengthens rather than weakens during El Niño-related relaxations of the trade winds). The “greenhouse effect” of increased atmospheric water vapor in the eastern Pacific during El Niño phases seems to provide the best available explanation for this out-of-phase relationship. Moreover, our analysis of newly-assembled longer data series suggests that variations of upwelling-favorable winds ascribable to local water vapor fluctuations are not limited to those directly linked to the ENSO cycle. These findings thus appear to represent a successful multiple-realization proxy empirical test of the earlier hypothesis that continued atmospheric greenhouse gas buildup will lead to intensification of coastal upwelling in most coastal upwelling regions of the world’s oceans. However, in case of the Benguela, where ENSO-associated variability in atmospheric water vapor content over the southern African continental landmass appears to vary in significant opposition to that of the eastern Pacific systems, the effect of projected declining ENSO system intensity on local water vapor content could tend to overbalance the local effects of increasing global concentrations of anthropogenic greenhouse gases, potentially explaining a reported declining (i.e., opposite) tendency in upwelling-favorable winds in that region.
2 June, 12:45 (PL2 OP1)
Surface winds along the eastern boundary upwelling systems in future climate scenarios R. Garreaud and M. Falvey Department of Geophysics, Universidad de Chile, Blanco Encalada 2002, Santiago, 2777, Chile. Email:
[email protected]
In this work we describe and interpret global-scale surface wind changes between present day conditions (baseline time slice: 1970-1999) and those projected for the end of the 21st century under the A2 IPCC scenario (A2 time slice: 2070-2099), with emphasis on the four major EBUS (Benguela, California, Canary and Humboldt). Evaluation of these changes are a key step to predict the regional environmental impacts of global climate change -linked to anthropogenic greenhouse gas increases- upon EBUS. Our primary dataset are the output from 21 coupled Global Circulation Models (GCM) integrations performed for the IPCC 4th Assessment Report. A particularly strong and consistent signal among the models is an increase in SLP along the poleward flank of the subtropical anticyclones (maximum at about 40° of latitude), modest changes at tropical latitudes, and a decrease at higher latitudes. This pattern has been linked with both an expansion of the Hadley circulation and a poleward shift of the extratropical storm tracks. The low-level winds along the EBUS are in an ageostrophic balance between the meridional pressure gradient and the friction. Therefore, the ΔSLP pattern leads to enhanced equatorward flow along the EBUS at subtropical latitudes (maximum at about 30° of latitude). The increase of upwelling-favourable winds is particularly 56
Eastern Boundary Upwelling Ecosystems Symposium marked and persist year round off the coast of south-central Chile, where ΔVs ~ Δvs ~ 1 m/s. Along the Canary and Benguela systems the changes are weaker (Δvs ~ 0.5 m/s ) and encompass an smaller area, but still persist year round. Off California, enhanced equatorward flow is restricted to boreal spring. The coupled GCMs don’t show a consistent change in the depth of the ocean mixed layer along the EBUS, therefore we can infer that the projected increase in upwelling-favourable, equatorward flow will tend to cool these coastal regions. Enhanced ocean eddy-activity (also forced by the stronger winds) can extend this cooling effect farther into westward. Indeed, the geographic pattern of projected surface air temperature change (ΔSST) shows minimum warming over the EBUS, particularly off south-central Chile, where the ΔSST of about 1°C is only half of the zonal average ΔSST at the same latitude. For the same region, we also found a good correspondence between the “anomalous regional cooling” and the increment of the local equatorward flow in individual models.
2 June, 13:00 (PL2 OP2)
Changes in the atmospheric forcing of upwelling in the Northern Benguela since 1960: regime changes and long-term trends K Peard1 and J-P Roux2 1 2
Formerly Ministry of Fisheries and Marine Resources, Lüderitz Marine Research, Namibia. Email:
[email protected] Ministry of Fisheries and Marine Resources, Lüderitz Marine Research, Namibia.
The strongest and most persistent upwelling cell of the Benguela Current system is the Lüderitz cell, considered the most active wind-driven upwelling cell of any eastern boundary current. From a 46-year time series of wind speed and direction measurements at Lüderitz lighthouse near the centre of the upwelling cell, we developed an annual net upwelling index and analysed the patterns of interannual variability in atmospheric forcing of upwelling together with changes in Sea Level Pressure. 1960 to 1975 was a period of low upwelling with only 5 years above long-term average. In contrast 1975 to 1988 was characterised by intense upwelling with 13 consecutive years of positive anomalies in wind stress. From 1988 to 2006 low and declining upwelling intensity prevailed with the last six consecutive years corresponding to the most negative anomalies of the entire series. Upwelling intensity has declined by more than 50 % from 1975 to 2006. These changes are accompanied by concomitant changes in Sea Level Pressure and changes in the frequency of occurrence of days with a northerly (downwelling favourable) component (increase), calm days (decrease), as well as a noticeable long-term increase in frequency of occurrence of days with a westerly component. Together these environmental parameters suggest that the atmospheric forcing mechanisms of upwelling in the Northern Benguela (interactions between the South Atlantic Anticyclone, the sub-Antarctic low pressure systems and the coastal lows) have changed dramatically over time. Since the Lüderitz cell is the main supplier of nutrients to the Northern Benguela, the observed changes in atmospheric forcing have had important implications for biological production in the region and are affecting the functioning of the entire ecosystem.
2 June, 15:15 (PL2 OP3)
Diatom transfer functions for sea surface temperature and primary productivity in upwelling areas: the Cupex Project C. Lopes1,2,3 F. Abrantes1 and A.C.Miz3 Marine Geology Department, INETInovação, Estrada da Portela, Zambujal, Amadora, 2721-866, Portugal. Email: cris.lopes@ softhome.net 2 Centre for Marine and Environmental Research, Portugal. 3 College of Oceanic and Atmospheric Sciences, Oregon State University, USA. 1
Marine productivity plays an important role in natural carbon dioxide (CO2) variations through the “biological pump”. This biological pump (mainly driven by diatom activity) is focused in specific regions, like the upwelling areas (less that 1% of the world’s oceans total area), which support high export production. In these areas, atmospheric CO2 can be transported into the ocean. Therefore, to understand natural variations in atmospheric CO2 and other oceanic properties, we must understand the long-term history of these regional upwelling systems. Because of the interrelation between wind-driven coastal upwelling and 57
Eastern Boundary Upwelling Ecosystems Symposium diatom domination in phytoplankton blooms, diatom time-series from such areas can provide important information on climate change related variability in upwelling and nutrient supply. Therefore, upwelling areas represent key regions for oceanic properties reconstructions, which can be approached by the use of diatom Transfer Functions (TFs). Since the early 80’s, TFs development became a major issue due to the extreme importance of understanding past ocean properties. However, the major focus has been on open ocean and calcareous microorganisms. Besides, the existing data for sea surface properties was a problem (data was cease and irregular), as such, some properties were more investigated than others. Today, with satellite data and better instrumental technologies, more and uniformly distributed information is available. Furthermore, the modern computer technology and power enable us to apply stronger and faster statistical tools and models. The development of TFs for coastal upwelling areas is one of the main goals of the CUPEX project: Coastal Upwelling Natural Variability: the last two Climate Extremes (21,000 ± 2,000 Cal-yr BP and 8,000 ± 1,500 Cal-yr BP), so that quantitative reconstructions of the environmental conditions of the last two past climate extremes: the Last Glacial Maximum and the Holocene Optimum are possible. Our environmental reconstructions comprise past nutrients content, sea surface temperature (SST) and primary productivity (PP), and the first results refer to the American coastal upwelling systems (the California and the Humboldt systems) and the Arabian Sea monsoon related upwelling system.
2 June, 15:30 (PL2 OP4)
Coastal upwelling, water renewal rates and the occurrence of harmful microalgae in the Rías Baixas (NW Spain) X.A. Álvarez–Salgado1, U. Labarta1, M.J. Fernández Reiriz1, F. Figueiras1, G. Rosón2, S. Piedracoba2, R. Filgueira1 and J.M. Cabanas3 CSIC, Instituto de Investigaciones Marinas, Eduardo Cabello 6, 36208 Vigo, Spain. Email:
[email protected] Universidad de Vigo, Facultad de Ciencias del Mar Campus Lagoas–Marcosende, Spain. 3 IEO, Centro Costero de Vigo, Spain. 1 2
The extension and intensity of the upwelling season in the NW Iberian Peninsula (42º–43ºN) have decreased by 30% and 45% over the last 40 years, respectively. Accordingly, the renewal time (τ) of the Rías Baixas, four large coastal inlets where 15% of the World extraction of blue mussels occurs, has increased by 240%. We indirectly demonstrate here that the growing τ has caused the increasing occurrence of harmful microalgae in these embayments, dramatically affecting mussel raft cultivation. The equation: τ ) D=365. 1-exp( — c1
explains 80% of the variability of the number of days per year that mussels cannot be extracted from the hanging ropes because of the occurrence of harmful microalgae (D). The coefficient c1 = 37± 2 days indicates that an average τ over the upwelling season of > 25±1 or 50± 3 days reduce mussel extraction to only 50% or 25% of the year, respectively.
2 June, 15:45 (PL2 OP5)
Impacts of climate variability and change on zooplankton dynamics in the coastal upwelling region of the northern California Current W. Peterson NOAA Fisheries , Hatfield Marine Science Center, 2030 S Marine Science Drive, Newport OR, 97365, USA. Email:
[email protected]
The California Current extends over 28° of latitude, from the northern tip of Vancouver Island Canada (51°N) to southern Baja California Mexico (23°N). The waters within this southward-flowing current warm and mix with offshore waters such that both temperature and salinity increase gradually in a southward direction. As a result, the biota transported in this current also show pronounced latitudinal differences in species composition, ranging from cold-water sub-arctic species in the north to warm-water subtropical and tropical species in the south. The northern end of the current is dominated by strong seasonal variability in winds, temperature, length of the upwelling season, plankton production and the spawning times of many fishes, whereas the southern end of the current has much less seasonal variability in these parameters. Recently, the Northern California Current (NCC) ecosystem has become more variable and more subtropical in nature, due to climate change (?). This observation is based on our long-term ongoing sampling of 58
Eastern Boundary Upwelling Ecosystems Symposium hydrography and zooplankton in the coastal upwelling zone off Oregon, at biweekly intervals, for the past 12 years. Results of this work has shown that variations in copepod biodiversity, species richness and community structure are coupled to the PDO suggesting that basin scale variations in wind direction, particularly in winter/spring, result in the transport and delivery of very different source waters to the NCC: during positive phase of the PDO (southwesterly winds in winter/spring over the northeast Pacific), subtropical waters feed the NCC and bring zooplankton of subtropical origin, whereas during negative phase of the PDO (northerly/northwesterly winds in winter/spring), boreal subarctic waters are the chief source waters to the NCC, bringing a sub-arctic fauna to the coastal upwelling zone. Knowledge of source waters is critical to understanding ecosystem dynamics in the shelf waters of the Northern CCE. When the PDO is in negative phase, waters from the Gulf of Alaska feed the NCC and transport large, lipid-rich copepods to the shelf waters of the NCC; however when the PDO is positive, waters from offshore and south of the NCC transport small, oceanic lipid-poor copepods to the shelf waters. Thus, changes in the sign of the PDO seem to result in local food chains that have vastly different bio-energetic content. There are clear links to fisheries in that salmon returns are well-correlated with both the PDO and with biomass of “northern” lipid-rich zooplankton species. Also, the trend towards a more sub-tropical NCC may explain the increased abundance of sardines in waters of the NCC, decreased abundance of osmeriids (a small pelagic fish species that is a key link between copepods and piscivorous fishes), and the recent observation of spawning of whiting in the NCC, a fish that normally only spawns in winter, in the southern California Current. Thus, it would appear that the NCC may be transitioning to a more subtropical ecosystem as a result of global warming.
2 June, 16:00 (PL2 OP6)
Upwelling enhancement and pelagic ecosystem responses off Peru since the late nineteenth century D. Gutiérrez1, A. Sifeddine2, I. Bouloubassi3, R. Salvatteci4, P. Tapia1, D. Field5, L. Méjanelle3, F. Velazco1, G. Vargas6 and L. Ortlieb2 IMARPE, Project MIXPALEO, Gamarra y General Valle s/n Chucuito, Callao, Callao 1, Peru. Email:
[email protected] IRD, UR Paléotropique, France. 3 LEOCEAN & Université Pierre et Marie Curie, France. 4 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE)/proj. MIXPALEO, Mexico. 5 Monterey Bay Aquarium Research Institute, USA. 6 Universidad de Chile, Departamento de Geología, Facultad de Ciencias Físicas y Mateméticas, Chile. 1 2
Multiproxy studies on sediment cores collected off Pisco(14°08’S), downstream the main upwelling center off Peru, and off Callao (12°01’S) reveal a positive centennial trend in upwelling intensity since the late nineteenth century which resulted in increasing productivity and in a centennial expansion of the Peruvian anchovy population. Sea surface temperatures (SST) derived from the alkenone unsaturation index (Uk37) off Pisco exhibit a negative trend since ca. 1870 (-0.015°C y-1, r2=0.45, n=63), with a more intense cooling during the past 50 years. Comparisons with 30-year instrumental records evidence that the range and tendency of alkenone SSTs correspond to coastal winter/spring SSTs, e.g. during the annual peak of upwelling winds. Thus, the Uk37–temperatures reflect the intensity of coastal upwelling. The intensification of coastal upwelling has probably resulted from a stronger regional forcing of alongshore winds as suggested by instrumental records of wind stress since the early twentieth century. Yet, local forcing of alongshore winds, as enhanced land-sea thermal gradient due to global warming, may have played an increasing role for the past 50 years. Overimposed interdecadal PDO-like variability can also be observed, manifested as warm periods or pauses within the centennial cooling trend. The centennial upwelling intensification has resulted in a bottom-up increase of primary productivity (as inferred by carbon fluxes) and pelagic fish productivity (as inferred by fish remain fluxes). Especially the relative abundance of upwelling diatoms in the Chaetoceros-free fraction (CF) and the northern population of the Peruvian anchovy have grown. Increased contribution of offshore diatoms to CF is roughly related with interdecadal positive departures from the trend, but a negative tendency prevails, consistent with the intense cooling. The variability of fish scale fluxes exhibited little relationship with the interdecadal upwelling changes. In the nineteenth century, the increase of anchovy scale fluxes off Pisco preceeds the increase observed off Callao, suggesting a northward expansion of the anchovy population. On the contrary, deposition of fish scales from sardine and offshore species rapidly vanished off Pisco before 1900, while relatively high fluxes persisted until ca. 1920 off Callao, suggesting a rapid northward retreat of these species from the 59
Eastern Boundary Upwelling Ecosystems Symposium Pisco area in response to cooling. The significant reduction of anchovy scale fluxes since the early 1960’s despite unprecedented strong upwelling forcing and productivity can be attributed mainly to the human removal of fish production. Parallel higher scale deposition for sardine and offshore species was recorded until the late twentieth century, when anchovy scale fluxes began to rise. Favourable environmental conditions set by the cooling trend have probably increased the population resiliency of the exploited anchovy stocks. Acknowledgments The authors acknowledge the support from IMARPE and IRD through the research projects PALEOPECES and MIXPALEO.
2 June, 16:15 (PL2 OP7)
Prey quality affects the production of wild Pacific salmon in the northern California Current ecosystem M. Trudel1,2, D. Mackas3 and A. Mazumder2 Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, Canada, V9T 6N7. Email:
[email protected] 2 Department of Biology, University of Victoria, Canada. 3 Fisheries and Oceans Canada, Institute of Ocean Sciences, Canada. 1
The marine survival of salmon has been observed to covary with climate and ocean conditions at small and large spatial scales. Several competing hypotheses have been proposed to explain these patterns. Although the specific mechanisms affecting the marine survival of salmon differ among these hypotheses, all generally agree that lower marine survival of Pacific salmon is associated with lower marine growth during their first year at sea. In this study, we examined the effects of ocean conditions on the growth and survival of Pacific salmon in the northern California Current System (CCS) and Alaska Costal Current (ACC), and developed forecasting models for the marine survival of Pacific salmon. Our work shows that, while plankton productivity and temperatures tend to be higher in the CCS, salmon are generally larger and fatter, and have higher growth in the ACC. The poorer growth and condition of salmon in the northern CCS appears to be related to a calorie-deficient diet rather than to lower rates of food consumption or to higher metabolic rates. This indicates that ocean conditions affect salmon production through changes in prey community composition and quality, which in turn are induced by the effects of climate on ocean circulation, and on the local success of different zooplankton life history strategies (year round activity vs seasonal dormancy and lipid accumulation).
2 June, 16:30 (PL2 OP8)
Top predator responses to environmental variability in the northern Benguela: implications for understanding the impact of climate change on the ecosystem J-P. Roux, J. Kemper and K. Peard Ministry of Fisheries and Marine Resources, PO Box 394, Luderitz, Namibia. Email:
[email protected]
The Benguela region is at a critical location in terms of global climate systems, and its marine environment is extremely vulnerable to climate change. In the northern Benguela, climate change is expected to affect the upwelling regime and alter the frequency and amplitude of Benguela-Niño anomalies. The Cape fur seal and the African penguin are two top predators feeding on epi- and meso-pelagic prey on the Namibian shelf. In the region of most intense upwelling, near Lüderitz, we found that in the past two decades biological (growth) and demographic (survival, recruitment) parameters of both species are affected by inter-annual variability in the wind-driven upwelling intensity. These responses are caused by mid-trophic level prey quality and availability and demonstrate that in this region atmospheric forcing variability affects the entire food web.
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Eastern Boundary Upwelling Ecosystems Symposium
PL2 Posters Poster: PL2 P1
Climate change impacts on the upwelling off the Western Iberian Peninsula J. Alves1, P. Miranda1 and N. Serra2 1 2
IGIDL / FCUL, Rua Virgilio Correia n 2 6 ESQ, Lisboa, 1600-223, Portugal. Email:
[email protected] University of Hamburg, Germany.
This study is focused on the upwelling dynamics off the Western Iberian Peninsula. It is based in the results of the ocean numerical model ROMS. A controlled simulation from 1960 until 1990 and a scenario simulation from 2070 until 2100 with reanalysis atmospheric data from the RACMO model were made in order to study the impact of climate change on the intensity and frequency of upwelling events off the Western Iberian Peninsula coast. A description of the upwelling in terms of currents, sea surface temperature and sea surface height variability was made. An Eulerian analysis of the surface wind and currents at three locations along the coast was also realised in order to make a comparative study between the direction and intensity of the surface winds and currents. In addition, a Lagrangian analysis based in the displacement of particles near the coast during an upwelling event was made, with the release of several virtual floats at the model ocean surface along the coast, which permitted the study of the displacement of plankton organisms present near the coast due to an upwelling event.
Poster: PL2 P2
Galapagos marine communities under strong oceanographic variability – the relevance of applying small scale subsets within large scale regional boundary systems S. Banks1, D. Ruiz1, M. Vera1, M. Toscano1, N. Tirado1, J. Morrison2 and M. Wolff1 1 2
Charles Darwin Research Station, Puerto Ayora, Galapagos, 17-01-3891, Ecuador. E mail:
[email protected] University of North Carolina Wilmington, North Carolina, USA.
The diverse marine biogeography of the Galapagos archipelago from cold water adapted species in the strong upwelling across the western isles to tropical coral communities in the far north is generated by a unique confluence of oceanic currents and a dramatic marine landscape that encompasses coastal platforms, submarine mountains and plunges on all sides to the deep abyssal plain. The resulting mix of circumtropical, indo-pacific, and temperate species that define their ranges within the 133,000 km2 of the Galapagos Marine Reserve (GMR) form ecosystems that are over small scales unique to the equatorial Pacific yet influenced by far larger eastern boundary current processes. They shift in distribution and composition within and between years, (with species often “stranded” outside the extremes of their normal provinces within upwelled cold water pockets contrasting sharply with periodic sustained warming episodes) and are dramatically affected by strong extremes of ENSO variation as evidenced by the strong El Niño years of 1982/83 and 1997/98. Analysis of subtidal rocky reef communities at two depth strata coupled with oceanographic surveys, satellite data and a sparse mooring array from 2004-2007 across the GMR shows large variability over seasonal and spatial scales closely correlated to changes in the predominant oceanographic regime. Species distributions are subject to small scale spatial patterning and temporal variability within larger ENSO signals and associated internal wave passage across the archipelago. Internal wave trains shoaling the mixed layer thermocline across the Galapagos platform have caused direct and indirect changes in community structure. Habitat forming species such as corals Porites lobata and Pocillopora Sp.for example show species specific mortalities with water temperature shock in the order of 10-12 0C in as little as 6 days at the 15m isobath during abrupt El Niño/ La Niña transitions that propagate through the marine community. Endemic cup corals such as the critically endangered Tubastrea floreana (IUCN, 2007) and deep water kelp Eisenia galapagensis have been found persisting only in isolated cold water pockets after strong warm events. Subtidal community distributions are examined to determine causal factors defining marine community composition, change in species distributions and variable responses between apparent biogeographic regions with a view to improved resource management. With much attention focused upon the largemesoscale effects of eastern boundary current systems, there is a need to examine how small scale 61
Eastern Boundary Upwelling Ecosystems Symposium ecosystem processes are moderated within such large climatic regional and global patterning. Current and future work explores the importance of subsetting regional physical forcing of marine community composition, biodiversity and endemism processes at higher resolution time (seasonal) and spatial scales (1-4 Km2) relevant to local resource use, sustainable management and conservation issues in Galapagos within extremes of large to mesoscale regional variations in the Eastern Tropical Pacific.
Poster: PL2 P3
Connection between mesoscale activity in the Peru-Chile current system and the equatorial Kelvin wave in ROMS (1/6°): 1992-2000 A. Bel Madani1,3,4, A. Chaigneau2,3,4, V. Echevin2,3, B. Dewitte1,3,4 and D. Correa4 LEGOS, 14, Av. Edouard Belin, 31400 Toulouse, France. Email:
[email protected] LOCEAN, Laboratoire d’Océanographie et du Climat: Expérimentation et Approches Numériques, France. 3 IRD, Marseille, France. 4 Instituto del Mar del Peru-Centro de Investigaciónes en Modelado Oceanográfico y Biológico Pesquero, Callao, Peru. 1 2
Oceanic variability along the western coast of South America is influenced by the equatorial Kelvin waves (EKW) at a variety of timescales, from intraseasonal to interannual frequencies. Coastal-trapped waves (CTW) originating from the equator can propagate along the coast, modify the stability of the regional current system and trigger extratropical Rossby waves (ERW) north of the critical latitude as well as eddies. In this study, an eddy-resolving regional circulation model forced with observed winds and realistic boundary conditions over 1992-2000 is used to investigate the impact of the EKW on mesoscale activity in the eastern south Pacific. The simulation, which is first validated from observations, reproduces realistically most aspects of the variability, especially during the strong 1997/98 El Niño event. A vertical mode decomposition at the equator is performed in order to derive the contribution of the EKW according to the most energetic baroclinic modes, which provides, as a first approximation, an estimation of the CTW variability. An Eddy identification and tracking algorithm is used to derive statistical characteristics of mesoscale activity in the model. Based on this simulation, it is shown that mesoscale activity along the Peru-Chile coast is tightly linked to EKW activity, with a relationship depending on the characteristics of the EKW (frequency, vertical structure and sign, i.e. downwelling versus upwelling). A focus is given on the analysis of the impact of the EKW prior to the development of the 1997/98 El Niño. Our results illustrate the sensitivity of mesoscale variability off the coast of Peru and Chile to the equatorial forcing.
Poster: PL2 P4
Recent trends in plankton and upwelling intensity off Galicia (NW Spain) A. Bode1, M.T. Alvarez-Ossorio1, J.M. Cabanas2, A. Miranda2 and M. Varela1 1 2
IEO, Centro Oceanográfico de A Coruña, Apdo. 130, A Coruña, 15080, Spain. Email:
[email protected] IEO, Centro Oceanográfico de Vigo, Spain.
The mean intensity of the northeastern Atlantic upwelling system at its northern limit (Galicia, NW Spain) decreased during the last 40 years. At the same time, warming of surface waters was detected. Plankton biomass and composition is expected to reflect such changes when integrated over large time and space scales. In this study, biomass, abundance and species composition of phyto- and zoplankton were analysed to search for significant patterns of anual change and related to upwelling intensity. Regionally integrated, mosly offshore, data were obtained from the Continuous Plankton Recorder (since 1958) whereas coastal data from Vigo and A Coruña came from the Spanish Atlantic Time-Series program (since 1990). No significant trends were found in phytoplankton biomass at either regional or local scales. However, there was a significant decrease in diatom abundance at regional scales and also of large species at local scales. Zooplankton abundance (mainly copepods) significantly decreased offshore but increased near the coast, particularly due to the abundance of small-sized species (e.g. Acartia). Biomass of zooplankton also increased near the coast, with the fastest rates in the south. Warm-water species, as Temora stylifera, were increasingly abundant at both regional and local scales. The large high-frequency variability of phytoplankton, and the contrasting results obtained for zooplankton suggest that the effects of large scale trends on the plankton are being effectively modulated by local factors in this upwelling region. 62
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL2 P5
Modelling stock dynamics of fish productivity in the eastern boundary upwelling ecosystem of Canary/Iberian Peninsula M.F. Borges1, H.Mendes1, N.Crato2 and J. Caiado2 1 2
Instituto de Investigação das Pescas e do Mar (IPIMAR), Avenida Brasilia,1449-006 Lisboa, Portugal. Email:
[email protected] Department of Mathematics, Instituto Superior de Economia e Gestão, Universidade Técnica de Lisboa, Portugal.
We propose to address the response of ecosystem productivity to the observed climatic decadal regime shifts by analysing time-series of different trophic components of the ecosystem during the last 40/50 years. Long-term regime shifts were analysed through time series analysis and recruitment variability is explored as a function of Spawning Biomass and environment using additive modelling.
Poster: PL2 P6
Non-Gaussian nature of ENSO signals and climate shifts: implications for regional studies off the western coast of South America J. Boucharel1, B. Dewitte1, B. Garel2, Y. Du Penhoat1 and C. Bosc1 LEGOS: Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, 14 av. Edouard Belin, Toulouse, 31400, France. Email:
[email protected] 2 Institut de Mathématiques de Toulouse (LSP), France. 1
The West coast of South America can be considered as an extension of the equatorial wave guide at a wide range of frequencies, which includes the whole spectrum of El Niño/Southern Oscillation (ENSO) variability. Thus, like the regional circulation off Peru, ENSO exhibits a significant modulation at decadal timescales which is also associated to changes of its characteristics (amplitude, frequency, propagation, predictability. Among these characteristics, some of them are generally ignored in ENSO regional studies, such as asymmetry (number of warm and cold events is not equal) and deviation of its statistics from those of an assumed Gaussian distribution. They tend to reduce ENSO prediction skill. These properties could be transmitted to the mode of variability along the coast of Peru, which could explain some aspects of the decadal Humboldt system circulation. Statistical tests were used to quantify the non-Gaussian nature and asymmetry of ENSO typical indices from in situ data and a variety of models (from intermediate complexity models to full physics coupled general circulation models). It was shown that ENSO can be accounted for by a non-Gaussian alpha-stable law (i.e. a more heavy-tailed distribution than Gaussian) and by non stationary processes dominated by mean state and empirical variance abrupt changes. This last issue was achieved by a shift detection method applied to ENSO typical indices. This supports the mechanism of ENSO rectification by the change in mean state to produce decadal variability. In particular, empirical variance shifts (assumed to be an index of low frequency variability) first detected in the western tropical Pacific, propagate (with propagation characteristics related to the unstable modes of ENSO) and grow eastward along the equator, leading to enhanced SST anomalies, asymmetry and well marked alpha stable properties off the west coast of Peru. Implications for the interpretation of proxies of the upwelling variability off the coast of Peru are discussed.
Poster: PL2 P7
Long-term nutrient changes in the southern Benguela upwelling region: an indication of climate change? J. Currie1, M. Lucas1, L. Hutchings2 and H. Waldron3 Zoology Department, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa. Email:
[email protected] Marine and Coastal Management, South Africa. 3 Oceanography department, University of Cape Town, South Africa. 1 2
A forecast of climate change on upwelling systems, is that an increasing thermal gradient between land and sea will result in greater equatorward winds driving greater upwelling intensity. Notable ecosystem changes have been documented in eastern boundary upwelling regions in recent decades, including the southern Benguela, where striking changes in zooplankton, pelagic fish, demersal fish, linefish, squid, 63
Eastern Boundary Upwelling Ecosystems Symposium rock lobster and seabird abundances have been shown. Nutrient availability has undeniable bottom-up effects on upwelling foodwebs, ultimately affecting pathways of energy flow through the ecosystem by mediating phytoplankton competition and succession. In this first long-term study of nutrient variability in the Benguela system, we compiled and interrogated historical nutrient, oxygen and hydrographic data from a defined geographic area incorporating St Helena bay. General linear models (GLMs) were applied to remove a seasonal effect and subsurface measurements were used to exclude a nutrient uptake signal from phytoplankton. Nitrate and phosphate concentrations both increased significantly between 1983 and 2004, by ~40% and ~50% respectively, while silicate showed no trend over this period. Although early records are patchy in time and space, phosphate concentrations suggest a decline from 1960 to 1983, whilst nitrate and silicate show no discernible trend. Oxygen concentrations showed a significant downward trend (~30%) between 1960 and 2004. The prominent increases in nitrate and phosphate, together with decreasing oxygen concentrations, suggest that there has been a parallel increase in primary productivity in the bay, leading to elevated decomposition (and oxygen utilisation) below the pycnocline. Despite a lack of long-term chlorophyll and wind datasets, our results point to a long-term increase in primary productivity, likely driven by increasing winds and hence intensified upwelling. The increase in nutrients and decrease in oxygen concentrations have important implications for biogeochemical cycles, ecosystems and commercial fisheries, and may have played an important bottom-up role in ecosystem changes in the Benguela region in recent decades.
Poster: PL2 P8
Impact of the intraseasonal Kelvin wave on the regional circulation of the Humboldt system: the idealised case B. Dewitte1,2, S. Thual1,2, V. Echevin3,2 and S. Purca2 LEGOS, Laboratoire d’Etudes Géophysiques et d’Océanographie Spatiale, 14 av. Edouard Belin, Toulouse 31400, France. Email:
[email protected] 2 Instituto del Mar del Peru-Centro de Investigaciónes en Modelado Oceanográfico y Biológico Pesquero (IMARPE-CIMOBP), Peru. 3 Laboratoire d’Océanographie et du Climat: Expérimentation et Approches Numériques (LOCEAN), France. 1
The equatorial Kelvin wave exhibits a significant variability at intraseasonal timescales. This variability is also apparently modulated at interannual to decadal timescales as revealed by the SODA oceanic Reanalysis, which could have a large impact on the regional circulation off Peru and Chile. Here a procedure was designed to couple a linear ocean equatorial model to the ROMS (Regional Ocean Modelling System) eddyresolving regional ocean model (1/6°) implemented in the Peru-Chile region. Academic experiments using idealized intraseasonal equatorial forcing were carried out with the objective to quantify how the solution deviates from linear theory which predicts that the Kelvin wave is trapped south of the critical latitude and the extra-tropical Rossby wave radiates north of it. Based on the results of a modal decomposition of the regional model variability, it was shown that there was significant deviation from the linear solution, which was due to a number of processes including modal dispersion and the non-linear interaction with the mean state and seasonal cycle. Sensitivity experiments to the characteristics of the equatorial forcing (frequency and skewness) are also presented.
Poster: PL2 P9
Hydrographic property means and time space variability along the southern extension of the California Current off Baja California, Mexico R. Durazo1,2 Universidad Autónoma de Baja California, Facultad de Ciencias Marinas, Km. 107 Carret. Tijuana-Ensenada, Ensenada, B.C., Mexico. Email:
[email protected] 2 Centro de Investigación Científica y Educación Superior de Ensenada, Depto. de Oceanografía Biológica, Km 107 Carret. TijuanaEnsenada, Ensenada, B.C., Mexico. 1
The program “Investigaciones Mexicanas de la Corriente de California (IMECOCAL)” has conducted 39 quarterly cruises between 1997-2007, along a subgrid of the original CalCOFI sampling of the coastal waters off Baja California (24-32N), Mexico. Data collected are used to compute hydrographic means and are compared to longer-term means computed for the period 1950-1978 (Lynn and simpson, 1987, 64
Eastern Boundary Upwelling Ecosystems Symposium hereinafter LS87). Results showed upper layer (0-100 m) temperature and salinity rms differences of both climatologies of 0.4 °C and 0.04, respectively. IMECOCAL seasonal mean surface geostrophic flows (0/500 dbar) showed the same trends as in LS87, except for small-scale (50-100 km) coastal circulation structures that arised due to a better spatial resolution sampling. At 200 dbar, IMECOCAL geostrophic currents (200/500 dbar) clearly define the California Undercurrent (CU) in all seasons but spring, when equatorward winds are stronger. In all other seasons, the CU is seen as the coastal poleward flow of two large scale eddies, cyclonic in the north (the deep expression of the Southern California Bight Eddy) and anticyclonic in the south. The two structures are separated off Punta Eugenia (28N), the main coastal promontory of the Baja California Peninsula. Climatological means were used to obtain the time-space variability at each station/depth sampled. Largest temperature and salinity anomalies (~8°C, 0.8) were associated to El Niño 1997-1998 off the central portion, Punta Eugenia. Salinity time-space series indicated the intrusion of fresher waters in the period summer 2002 through summer 2005. The variability in hydrographic properties suggests that 28° (Punta Eugenia) is a virtual boundary that separates north and south coastal regions.
Poster: PL2 P10
Effects of “El Niño” Event 2002-03 on soft-bottom macrobenthos community off the central and south Peruvian coast P. Gallegos, E. Ramos, K. Ortega and J. Tarazona Laboratorio de Ecología Marina, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Av. Venezuela s/n, Lima 1, Peru. Email:
[email protected]
The first El Niño of the twenty-first century occurred in 2002-03. According to standard ENSO indices, this event was of moderate strength and comparable to previous El Niños in 1986-87 and 1991-92. Largest SST anomalies were concentrated in the central equatorial Pacific; alternatively, SST anomalies were relatively weak and short-lived in the eastern Pacific and along the west coasts of America. Therefore, this study investigated the El Niño 2002-03 event and its effects on the community structure of soft bottom macrobenthos in both Ancon and Independencia Bay, on the central and south coast of Peru, during 20002004. During the period 2000-2004, oceanographic data and macrobenthos samples of soft bottom were obtained from two fixed stations in Ancon Bay (Lima, Peru) and Independencia Bay (Pisco, Peru) at 34 and 32 m of depth respectively. The number of species, average values of both density and biomass (ash free dry weight) of the soft bottom macrobenthos were investigated. The analysis of the thermal anomalies allowed the differentiation of three periods: January, 2000 to February, 2002; March, 2002 to March, 2003 characterised by positive anomalies greater to 0.5ºC related to EN event and April, 2003 to December, 2004. Analysis of variance and Scheffé a posteriori test of contrast was used in order to determinate differences between the periods and establish the relation of the ENSO event with the oceanographic and biological parameters. Cluster analysis was used to determine segments of time with high similarity in the community. Density data of the macrobenthos species was used. It was found that thermal anomalies were significantly different between the first and second period for both bays (p <0,05). Dissolved oxygen concentration revealed no significant differences among three periods for Independencia bay, whereas for Ancon Bay this parameter shows the same tendency than thermal anomalies. At Ancon Bay, the number of species and biomass revealed significant differences among three periods. Density revealed significant differences between the third and the other two periods. At Independence bay there were significant differences in number of species and density between the first and third period. Finally, there were significant differences in biomass between the second and the other two periods. Cluster analysis distinguished two groups to 40 % of similarity in both bays. The first one corresponds to the first and the second period and the second one to the third period, based on anomalies of temperature. It was concluded that in spite of thermal anomalies did not reach high values, these revealed significant differences before and during EN event. Besides, El Niño event 2002-03 of weak intensity produced significant changes in soft - bottom macrobenthos community on central and south coast of Peru, as those previously reported for El Niño events 1982 – 83 and 1997 – 98 on central Peruvian coast. 65
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL2 P11
Phytoplankton biomass and primary production variability in the California Current off Baja California from 1998 to 2007 G. Gaxiola-Castro, M. De-la-Cruz and J. Cepeda-Morales Departamento de Oceanografía Biológica. División de Oceanología. Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). Ensenada, Baja California. Mexico. Email:
[email protected]
In situ primary production and phytoplankton biomass data have been obtained quarterly since 1998 in the California Current off Baja California under the oceanographic IMECOCAL program, to understand the pelagic ecosystem response to climate variability. Phytoplankton samples were taken from the euphotic zone on surveys realised during spring, summer, autumn, and winter seasons. Temporal variability of water-column integrated phytoplankton biomass can be characterised mainly by four events. Low values during El Niño 1997-98, high biomass in La Niña 1999-2000, anomalous higher phytoplankton in 20012002, and lower values from 2003 to 2006 under a strong influence of low salinity and warmer surface waters. In general, lower and higher phytoplankton biomass can be associated with positive and negative Pacific Decadal Oscillation (PDO) index anomalies, respectively. Seasonal sea temperature anomalies off Baja California calculated at surface and 200-m depth follow the PDO index, indicating a response of the IMECOCAL zone to the large scale oceanic variability. Source of the warmer and anomalous low salinity surface waters are not very clear, generating negative anomalies in phytoplankton biomass from 2003 to 2006. In general, phytoplankton biomass trend were contrary to zooplankton biomass, indicating an apparent “top-down” control off Baja California. Primary production was higher, with mean values of ~1.5 gC m-2 d-1, generally during summer 1999 and autumn 2003. Changes in primary production were more associated with local conditions of natural solar light, sea temperature, and mesoscale processes. Primary production spatial variability was very large along the Baja California coast, mainly during 1999-2000 and 2002-2003 years.
Poster: PL2 P12
Seasonal mixed layer temperature and salinity variability in the tropical boundary of the California Current J. Gomez-Valdes and G. Jeronimo Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California, 22860, Mexico. Email:
[email protected]
In eastern boundary currents, eddies, meanders, and coastal upwelling are the main processes in the generation of mesoscale variability. Seasonal changes of mixed layer (ML) temperature and ML salinity in the southern part of the California Current were examined using hydrographic data from thirty six surveys, on a quarterly basis, carried out from 1997 to 2007 over a grid based on the Mexican Research of the California Current (IMECOCAL) stations plan. The spatial patterns of the first leading Empirical Orthogonal Function (EOF) for both ML temperature and ML salinity showed a single-signed distribution where the variability increases equatorward. We hypothesised that this pattern is explained by local forcing. To test our conjecture, we used sea surface height anomalies (SSH) and net heat flux anomalies (NHF) data from satellites. The EOF-1 of ML temperature was correlated with the first mode of SSH and NHF, while the EOF-1 of ML salinity was correlated with the second mode of SSH. So only the principal mode of ML temperature variability is explained by local forcing. The spatial pattern of the second leading EOF for the ML temperature showed a double-signed distribution, separating the costal zone from the transition one. This mode was weakly but significantly correlated with EOF-3 of SSH. But it was better correlated with costal upwelling index. The spatial pattern of the second leading EOF for the ML salinity showed a double signed-distribution, separating the northern region from the southern region off Punta Eugenia. This mode was correlated with the EOF-3 of SSH. The third leading EOF of both ML temperature and ML salinity were no correlated neither with SSH nor with NHF. It suggests that the lower mixed-layer thermodynamic modes are not related to local forcing. 66
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL2 P13
Using statistical and dynamical downscaling to assess climate change impacts on the Peru-Chile upwelling system K. Goubanova1, V. Echevin1, A. Bel Madani2, B. Dewitte2 and A. Chaigneau3 LOCEAN, UPMC, 4 Place Jussieu, Paris, 75005, France. Email:
[email protected] LEGOS/IMARPE, Peru. 3 LOCEAN/IMARPE, Peru. 1 2
The Humboldt current system is the most productive upwelling ecosystem of the world ocean with very high stocks of pelagic fish captured nearshore. These stocks have fluctuated significantly at interannual to decadal scales in the past decades and the social and economical impacts of the fluctuations due to climate change could be tremendous in the next century. In this work, the impact of climate change on the regional ocean circulation off Peru and Chile is investigated. The ROMS (Regional Ocean Modelling System) 1/6° eddy-resolving regional ocean model is used as a dynamical downscaling tool for the ocean circulation. Initial and open boundary conditions for the ocean were extracted from the global ocean-atmosphere coupled model IPSL-CM4 which was run under the 2xCO2 and 4xCO2 climate change scenarios. Due to their coarse spatial resolution, the atmospheric surface fields, wind stress and heat fluxes, were first downscaled using a statistical method based on canonical correlation analysis. This method is validated on present climate conditions using ERS and QuikSCAT satellite wind products. The derived high-resolution atmospheric forcing is then used to force the regional ocean model with prescribed conditions at the open boundaries from the IPSL-CM4 model. The regional simulations corresponding to the 2xCO2 and 4xCO2 climates are analysed in terms of mesoscale characteristics, coastal wave activity and upwelling intensity.
Poster: PL2 P14
Influence of persistent low salinity on the zooplankton from the Mexican sector of the California Current B. Lavaniegos Departamento de Oceanografía Biológica, CICESE, km 107 Carretera Tijuana-Ensenada, Apdo. Postal 360, 22860 Ensenada, Baja California, Mexico. Email:
[email protected]
The California Current system (CCS) is one of the large eastern boundary upwelling ecosystems. Total extension of the current influences the west coast of American continent from Vancouver Island, Canada, to the tip of Baja California peninsula. The CCS displays from north to south, an increasing gradient of temperature and salinity, coupled with an enrichment of tropical fauna. Therefore, the Mexican sector is the most subtropical of the CCS, and the presence of temperate fauna is usually limited to northern Baja California. A period of anomalous intrusion of subarctic water, which started in July 2002, has carried high densities of temperate species south into the Baja California waters. High zooplankton biomasses have been recorded. Evidence from euphausiids indicate expanded distribution of some subarctic species, such as Euphausia pacifica and Thysanoesa spinifera. These species have expanded their distribution southern of Punta Baja (30°N). Surprisingly, tropical fauna has maintained spatial positions and abundances in the region, despite of subarctic intrusion. This coexistence of both types of fauna could be brought about by a strong stratification of the water column, providing well separated niches. Uncertainties exist as to how the upwelling processes have continued working in the Baja California region, inspite of the strong stratification of the upper layer.
Poster: PL2 P15
Oceanographic conditions off northern Chile during La Niña 2007 J. Letelier, H. Reyes, M. Braun and M. Pizarro Av. Blanco Encalada 839, Valparaiso, 2340000, V region, Chile. Email:
[email protected]
From September 21st until October 15th of 2007, the MOBIO 2007 cruise was carried out, and 100 oceanographic stations between the latitudes 18º25’S to 24º 20’S were developed. The stations were distributed along transects, perpendicular to the shore, from 2 to 180 Km along the shore. Temperature, 67
Eastern Boundary Upwelling Ecosystems Symposium salinity and oxygen between surface and 500 m of depth were recorded. Also, images in the satellite (AVISO) of see level anomaly and geostrophic circulation were analysed, in order to characterise the activity of mesoscale eddy. The results showed the presence of negative strong anomalies in temperature and salinity between the surface and 100 m depth in the whole area. The anomalous fluctuations were from -1º to -1.5º C and from 0 to -0.4 psu on the surface, the highest absolute values involved the oceanic area. The distribution and magnitude of these anomalies show a decrease in the amounts of subtropical waters coming from the north, and also showed an increase in the subantartic waters. During this period a high presence of cyclonic eddies and strong sea level negative anomalies were observed. In addition a weakening of the thermocline, an abnormal rise of 15°C isotherm and the upper boundary of the oxygen minimum (1mL/L) was observed. The development of La Niña 2007 event, in the tropical zone caused a change in the proportion and composition of the northern Chilean waters, change associated to the sea level negative anomalies. Even so, the typical oceanographic physical process in the northern region, as the coast upwelling, fronts and mesoscale eddies persisted during September 2007. The concentrations of superficial and integrated chlorophyll also were not very different from other years.
Poster: PL2 P16
Climate change effects over the northwest African upwelling ecosystem J. Marcello1, A. Hernández-Guerra2, F. Eugenio1 and A. Fonte1 Signal and Communications Department. University Las Palmas of Gran Canaria, Campus Universitario de Tafira. Edificio de Electrónica y Telecomunicación, 35017 Las Palmas de Gram Canaria, Spain. Email:
[email protected] 2 Marine Sciences Faculty, University of Las Palmas of Gran Canaria, Spain. 1
Climate change is one of the major factors likely to affect the Earth’s ecosystems in the coming decades. A mean increase in the global temperature of 0.6ºC has been measured over the 20th century affecting our oceans. Especially, changes in the coastal upwelling ecosystems need to be accounted for as these structures are responsible for an important percentage of the global fish catch, for the primary and secondary productivity and for the atmosphere-ocean exchange. This paper aims to assess the impact of the climate change in the coastal upwelling regions located in the Northwest African coast (latitudes 5º to 36º). This area is one of the major upwelling regions in the world, so it is of great importance to study and predict the variability that measured parameters may have in the future. Remote sensing imagery has been used to perform this retrospective study; however, the enormous amount of data to analyse necessitated the development of automatic detection tools. Particularly, weekly sea surface temperature AVHRR 4 Km GAC data, from years 1985 to 2005, have been used. We have implemented a new methodology that overcomes the problems of identifying oceanographic mesoscale structures using a variety of image processing techniques and oceanographic knowledge about the region. In this new methodology, the upwelling is segmented after a pre-processing step that filters and applies quality masks, a feature extraction step that uses optimum automatic thresholding algorithms (Riddler, Otsu, Pun, Li, Hertz, Gaussian Mixture Model and Yanowitz) over a region of interest and a post-processing step that includes a morphological cleaning to eliminate isolated components not belonging to the structure. The main parameters assessed in this 20-years period were the upwelling index and the front distance to the coast. After studying more than one thousand images, with good latitude resolution, interesting data about the spatial, seasonal and long-term variability of the different upwelling ecosystems have been recovered.
Poster: PL2 P17
Climate variability and upwelling dynamics. Are they linked in NW Africa? C. Meiners, L. Fernández and A. Ramos Calle Hidalgo No. 617. Col. Río Jamapa, Boca del Rio, Veracruz, 94290, Mexico. Email:
[email protected]
The atmosphere and ocean dynamics are closely linked by process related with heat interchange and momentum transferring. The NW African coast is part of the Canary Current System (CCS), which is one of the four largest eastern boundary upwelling systems (EBUS). It supports large international large scale fisheries based on its high productivity rate due to the wind induced upwelling processes. The Azores High pressure centre drives the CCS and together with the Icelandic Low pressure center constitutes the dipole responsible of the robust pattern of climate variability in the North Atlantic, which is well described 68
Eastern Boundary Upwelling Ecosystems Symposium by the North Atlantic Oscillation (NAO) index. If the variability of pressure centers determines the intensity, direction and frequency of wind fields, westerlies at North, and trade winds in NW Africa, we expect that these pressure changes (NAO index) are responsible of the upwelling production along NW African coast. To test this hypothesis we performed a time series analysis between annual NAO index as a large-scale proxy of climate variability, the wind stress v-component (North-South) from ICOADS data, as a proxy of upwelling conditions and area integrated satellite data of Chlorophyll a from Giovanni NASA’s online interface, as a biological expression of successful upwellings. There was a positive relationship between climate variability and wind stress between 1960 and 2006, NAO index explained 41% of PC1 of wind stress v-component variability. In the same way, the PC1 of wind stress v-component were highly correlated with Chl a concentration between 1997 and 2006 (r = 0.90; p<0.001) explaining the 81% of Chl a variability. Finally the correspondence between NAO index and Chl a concentration was high as well (r = 0.79; p<0.01) between 1997 and 2006, which means that the climate proxy explained 63% of Chl a concentration along NW Africa. This kind of step by step quantified links between the atmospheric activity and their expression in CCS could be a useful tool to take in account in ecosystem modelling as environment variability proxy.
Poster: PL2 P18
Ichthyoplankton transport in NW Africa upwelling filaments M. Moyano1, J.M. Rodríguez2 and S. Hernández-León1 1
Biological Oceanographic Laboratory, Facultad de Ciencias del Mar, Universidad de Las Palmas de G.C., Campus Universitario de Tafira. 35017. Las Palmas de Gran Canaria. Canary Islands, Spain. Email:
[email protected]
2
IEO, Centro Oceanográfico de Gijón, Spain.
Dispersal processes of early life stages of fish play a determinant role in the success of its recruitment. A case of study of the transport of fish larvae of small pelagic fish in filaments shed from the NW African upwelling towards the Canary Islands. In this work, weekly surveys were carried out around the island of Gran Canaria from October 2005 to June 2006 to evaluate the influence of those mesoscale structures on the local ichthyoplanktonic community. A total of 156 taxa were identified, belonging to 51 families and 15 orders, which demonstrated the high fish diversity in the area. Myctophidae was by far the most abundant family (30%), followed by Sparidae (11%), Clupeidae (9%) and Gonostomatidae (7%). As expected in an oceanic island, neritic and oceanic taxa were represented in similar percentages. Clupeoids were the target of our study as those species were previously considered good tracers of filament structures in this area. Sardina pilchardus was scarce during the whole sampling period but appeared coinciding with filament events approaching the island. Larval and adult abundance of S. pilchardus declined during the last decades, meanwhile Sardinella aurita appeared to be strengthened suggesting a replacement between these two species.
Poster: PL2 P19
Increased eddies activity off Northern Chile during the last 500.000 years: deep-sea benthic foraminifer evidences? S. Núñez-Ricardo1,4, M. Marchant2, D. Hebbeln3 and C. Lange4 Graduate Program in Oceanography, Department of Oceanography, University of Concepción, P.O. Box 160-C, Concepción, Chile. Email:
[email protected] 2 Department of Zoology, University of Concepción, Chile. 3 Center for Marine Environmental Sciences, University of Bremen, Germany. 4 FONDAP-COPAS, University of Concepción, Chile. 1
Deep-sea benthic foraminiferal assemblages from the Iquique Ridge off northern Chile (25ºS) were investigated to evaluate the relationship between faunal composition patterns and paleoceanographic changes during the last 1 million years. We distinguished two main periods mainly based on benthic foraminifera faunal changes (assemblages, infaunal vs epifaunal and accumulation rates) during the last 1 myr: Interval 1 (encompassing Marine Isotope Stages, MIS 25-11, ~1000-406 kyr) is characterised by marked fluctuations in Benthic Foraminiferal Accumulation Rates (BFAR) (not shown) and in the relative abundance of organic carbon-related species especially after the Mid-Pleistocene Transition (MPT; 0.9 myr), suggesting strong carbon flux fluctuations but with mostly continuous food supply, that are accompanied 69
Eastern Boundary Upwelling Ecosystems Symposium by the extinction of species of the group Stilostomella. On the other hand, during Interval 2 (~ 338 kyr to MIS 1) the dominance of Epistominella exigua (MIS 9 & 10) and Nutallides umboniferus (MIS 8 & 5-6) can be interpreted as reflecting intermittently pulsating inputs of food that may be the result of a significant environmental change after MIS 11 (i.e. the Mid Bruhnes Event, MBE). Although a previous work suggest that our core site (GeoB 3388) is only affected by circulation changes, the appearance of pulses of E. exigua suggest increased productivity and mesoscale eddies activity after the MBE. Acknowledgements: Deutscher Akademischer Austausch Dienst (DAAD) and MECESUP-UCO 002; FONDECYT 2004 Project No. 1040968
Poster: PL2 P20
Modelling the inter-annual variations of the Benguela upwelling system P. Penven1, J. Veitch2, N. Chang2 and F. Shillington2 IRD, Laboratoire de Physique des Oceans (LPO), UMR 6523 (CNRS, Ifremer, IRD, UBO), Centre IRD de Bretagne, BP70, 29280 Plouzane, France. Email:
[email protected] 2 Department of Oceanography, University of Cape Town, South Africa. 1
Although directly driven by local coastal winds, the coastal upwelling systems are also largely influenced by large scale oceanic structures. This is true for the mean state but also for the inter-annual variations. The dramatic effect of the equatorial dynamics on the Peruvian upwelling system during El-Niños events is a characteristic example of such large scale oceanic influence. Along the West coast of Southern Africa, the Benguela upwelling system is delimited in its Southern and Northern boundaries by warm waters. In the North, the Benguela meets the southward owing Angola Current which is directly under the influence of the Equatorial Atlantic. In the South, the western boundary current of the Indian Ocean, the Agulhas Current, retroflects and spawns large anticyclonic structures: the Agulhas Rings. This way, the Agulhas Current brings warm and salty waters from the Indian Ocean which affects the baroclinic structure of the Benguela upwelling system. On inter-annual time-scales, in the Northern Benguela, the Equatorial Atlantic forces variations known as “Benguela-Niños". In the south, the Agulhas Current responds to variations in the wind stress curl integrated on the whole Indian Ocean. Local atmospheric wind forcing responds to global signals such as ENSO. SAfE (Southern Africa Experiment), a regional model configuration, is designed and analysed to disentangle the different influences on the variability of the Benguela upwelling system. A coastal nested zoom resolves the upwelling with a sufficient horizontal scale, while a larger scale regional model is able to drive properly the remote oceanic influences. Global Oceanic model solutions force the large scale influence at the open boundaries. The regional model is sufficiently large so the local systems such as the Angola Current or the Agulhas Current get enough room to develop properly. The model is able to reproduce the major aspects of the circulation and mesoscale dynamics. A model/data comparison is conducted to test the reproduction of the inter-annual signals. A model analysis is then performed to quantify the major drivers of the inter-annual variability in the Benguela upwelling system.
Poster: PL2 P21
Environmental changes in Western Iberia over the last 200 years as evidenced by marine dinoflagellate cyst records S. Ribeiro1, M. Ellegaard1, F. Abrantes2 and A. Amorim3 Faculty of Sciences, University of Copenhagen, Department of Biology, Øster Farimagsgade 2D, Copenhagen, DK – 1353, Denmark. Email:
[email protected] 2 LNEG-LGM (ex-INETI), Departamento de Geologia Marinha, Portugal. 3 Faculdade de Ciências, Universidade de Lisboa, Portugal. 1
Results from a high-resolution palaeoecological study based on sediment cores collected from three areas of the Western Coast of Portugal (Iberia – Canary EBUS) will be presented. Coastal upwelling systems are one the most productive in the world. Primary productivity in these systems is determined by a complex interaction of light conditions, nutrient availability, and water-column dynamics of stratification and mixture. Phytoplankton groups are particularly good indicators of climate change. Evidence suggests that they are more sensitive indicators of variations than environmental variables themselves, because the non-linear responses of biological communities can amplify subtle climatic perturbations. Dinoflagellates account for a significant amount of total phytoplankton biomass in coastal ecosystems, often forming blooms along the 70
Eastern Boundary Upwelling Ecosystems Symposium W Iberian coast. In order to assess the real extent of global climatic changes, in general, and for EBUS in particular, it is necessary to apply suitable retrospective tools. The analysis of sedimentary sequences where remains of past biological populations are preserved is of great importance in this context, and can help identifying past climatic signals as well as future trends. Dinoflagellates have proven useful in climate studies. Many species of this group produce organic-walled cysts that, unlike other microfossils, are generally well preserved in marine sediments. This work documents and discusses environmental changes in the upwelling system of Western Iberia (Ave/Douro, Lis, and Mira areas), by means of a palaeoecological approach based on dinoflagellate cysts. This study is part of a multidisciplinary approach to investigate climate variability off the upwelling coast of Portugal, which includes sedimentological and geochemical data, together with information from other biological proxies (diatoms and foraminifera).
Poster: PL2 P22
Potential for tracking the evolution of the Benguela system along the South African coast using molluscan isotopes D. Roberts1, A. Carr2 and A. Boom2 1 2
Council for Geoscience, PO Box 572, Bellville 7535, Republic of South Africa. Email:
[email protected] Department of Geography, University of Leicester, United Kingdom.
Marine mollusc shells constitute excellent archives of environmental records because of two key characteristics: firstly, shell chemistry (principally environmentally-sensitive elements/isotopes) and mineralogy are influenced by variables such as ambient salinity, temperature and water chemistry; secondly, shell deposition is virtually continuous, providing a near continuous record during their lifespan. The relatively brief snapshot in time provided by shell isotope analyses (ranging up to ~10 years) is offset by the high resolution record obtained. Such resolution is impossible for the more commonly analysed foraminiferan tests, where a number of individuals are usually analysed per sample. Furthermore, the age of fossil mollusc shells can be readily determined by the well established and relatively cheap method of radiocarbon dating up to an age of <30 ka. The arid southern African west coast is presently washed by the cold Benguela system with associated cold, nutrient-rich upwelling systems driven by prevailing southerly winds. Accordingly this coastline has since the Pleistocene hosted a thermophobic (cold water) molluscan fauna. Given the well established chronology for marine terraces up to 50 m asl with ages ranging from Pliocene to Holocene, the potential for using shell geochemistry to explore near-shore Atlantic palaeo-oceanography is considerable. Whereas a thermophobic molluscan fauna now dominates along the west coast, late Neogene faunas have included many extant and extinct thermophyllic species, as well as extralimital taxa now found exclusively in warmer waters. Thus the mollusc shells would document profound changes in water chemistry and temperature over the Neogene along the west coast. Deepsea drill cores have previously produced evidence for such oceanographic fluctuations, but the onshore record is almost entirely lacking. Fossil Donax from the earlier Pliocene 50 and Middle-Late Pliocene 30 m beaches of the West Coast both showed lighter isotopes than their recent and Holocene counterparts and the 50 m beach was notably lighter than the 30 m one. These results are a function of water temperature and sea level, but since the sea level is known a correction can be made. It is concluded that paleosea temperatures (probably the most influential control/indicator of climate in general) can be reliably reconstructed from fossil molluscs.
Poster: PL2 P23
Study of the interannual variability of the Iberian and Canary upwelling system A. Teles-Machado1, Á. Peliz2 and J. Dubert1 Departamento de Física da Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Aveiro, Portugal. Email:
[email protected] 2 Instituto de Oceanografia, Universidade de Lisboa, Portugal. 1
A considerable knowledge about the main circulation features of Iberian and Northern Africa - north of Canary Islands - Upwelling System has been achieved in the last decades. However, although interannual and longer term fluctuations of the system have been reported, the mechanisms driving this variability still need to be investigated. We present preliminary results of an ongoing modelling study of the main variability modes of the Iberian and Northern Africa upwelling system. The study aims at understanding/partitioning the main factors affecting the statistical structure of this upwelling region dynamics, namely the internal (oceanic variability), the external (atmospheric forcing) and the remote (anomalies advected to the region). We use
71
Eastern Boundary Upwelling Ecosystems Symposium the ocean model Regional Ocean Modelling System (ROMS) to simulate the past 40 years of the ocean. The model domain was chosen in order to include the Iberia and northwest Africa upwelling regions (north of Canary islands) at base horizontal grid resolution of nearly 1/8º. Various experiments are to be done using both climatological and reanalysed atmospheres. For the ocean boundaries we use both climatological ocean boundaries and a downscaling of the global ocean model ORCA at 0.25º.
Poster: PL2 P24
A surplus production model including the effect of environment: application to the white shrimps stocks in Senegal M. Thiaw1, D. Gascuel2, D. Jouffre1 and O. Thiom-Thiaw3 Institut de Recherche pour le Développement US Osiris, Dakar BP 1386, Senegal. Email:
[email protected] UMR Ecologie et Santé des Ecosystèmes, Pôle Halieutique Agrocampus Rennes, France. 3 Institut Universitaire de Pêche et d’Aquaculture, Senegal. 1 2
Exploitation of the white shrimps (Penaeus notialis) by trawlers recently became a major fishing activity in several Western African countries. In Senegal, two stocks are intensely exploited: the north one around SaintLouis and the Roxo-Bijagos stock in the south (the largest stock). The life cycle of shrimp is very short and recruitment is usually considered highly dependant of intensity. Thus, fisheries management has to take into account diagnosis based on stocks assessment, but also to adapt to environmental variability. Using a surplus production model which includes an additional effect of environment, we analysed changes in abundance that occurred for the two stocks during the past 10 years. Based on GLMs techniques, yearly abundance index are estimated from commercial catch statistics. Derived from these indices and from total catches, theoretical fishing efforts were calculated. Two environmental indices were alternatively tested in the model. One measuring the coastal upwelling intensity from wind speeds provided by the SeaWifs database; the other is related to the primary production derived from satellite infrared images of chlorophyll a (NOA database, http://las.pfeg.noaa. gov). Models were fitted to the 1996 to 2005 time series and express the abundance of each stock as a function of the fishing effort and the environmental index. For the northern stock, the model based on the index of upwelling intensity explains 77.9% of the year-to-year variability. Fishing effort and abundance fluctuates over the period without any clear trends, and the stock seems to be still underexploited. The abundance of the stock mainly depends on the primary production, which explains 42.7 % of the total variance. For the southern stock, the best fit was observed using the primary production index (R2 = 0.852). Fishing effort strongly increased during the period, while the abundance has been reduced by 4-fold over the past 10 years. The stock is nowadays significantly overfished, whatever the environment could be. Nevertheless, upwelling intensity explains 13.3 % of the variance and results in significant changes in predicted catches. MSY for instance varies from 1200 to 1800 tons for respectively the lower and the upper values of the observed interval of yearly upwelling indices. Ecological processes, which determine the observed environmental effects, are finally discussed. The early-life planktonic stage of shrimps is known to be the main critical period of the life cycle and recruitment especially depends on the productivity occurring in the area of reproduction. In the north of Senegal the seasonal upwelling is highly variable from year to year and constitutes the major factor determining this productivity. In the South, hydrodynamic processes seem to dominate and determine the primary production.
Poster: PL2 P25
Species composition, abundance and spatial distribution of coastal fish and their relation with habitat structure of north Chilean kelp beds M. Villegas1, J. Laudien2, W. Sielfeld1 and W. Arntz2 1 2
Departamento de Ciencias del Mar, Universidad Arturo Prat, Casilla 121, Iquique, Chile. Email: Email:
[email protected] Alfred Wegener Institute for Polar and Marine Research, Germany.
Northern Chilean kelp habitats are dominated by monospecific Macrocystis integrifolia beds, Lessonia trabecutata beds or patches of L. trabeculata colonising barren grounds. The habitats provide distinct three-dimensional structures, which are affected by the El Niño Southern Oscillation (ENSO), which in turn is likely to alter the associated coastal fish community. Thus, the present study aimed to examine whether species composition, abundance and spatial distribution of fish communities are driven by the three distinct habitat structures. Seasonally (between fall 2006 and summer 2006/2007) 15 sampling units 72
Eastern Boundary Upwelling Ecosystems Symposium (10 m2 each) of any of the three habitats were examined using SCUBA diving to record sporophyte density, fish composition, fish abundance and spatial distribution in Chipana (21º 19’ S). A total of 36 sporophytes of the respective kelp collected from each habitat revealed maximal holdfast diameter, number of dichotomies per stipe, total plant length, stipe number, frond width, and wet mass. Multivariable analysis reveal that dense L. trabeculata kelp bed showed significantly higher fish species richness, abundance and diversity compared with the M. integrifolia habitat, whose fish community did not significantly differ from that of the L. trabeculata patches. In turn the latter is characterised by significantly lower abundances compared with the dense L. trabeculata bed, however, species richness and diversity did not strongly differ. Principal Component Analysis (PCA) revealed that the Peruvian morwong C. variegatus, Pacific chromis C. crusma, and Coquito sergeant N. latifrons explained most of the variability (18%) between kelp habitats. The most characteristic kelp fish C. variegatus was negatively related with kelp abundance, stipe number, wet mass, holdfast and frond width, and positively related with dichotomies per stipe, plant length and stipe number of L. trabeculata morphology. Thus kelp habitat complexity may modulate fish assemblages as a result of interaction between kelp and fish (shelter and habitat for prey), and vice versa (herbivory, control of herbivores). Therefore habitat variations on a spatial or temporal scale as observed during and after El Niño events may modulate coastal fish communities.
Poster: PL2 P26
Southward shift of export productivity maxima during glacial cold periods off the western Iberian Margin A. Voelker1,2, E.Salgueiro1,2, and L. de Abreu1,2 Laboratorio Nacional de Energia e Geologia; Dept. Geologia Marinha; Estrada da Portela, Zambujal; 2721-866 Alfragide; Portugal. Email:
[email protected] 2 CIMAR Associated Laboratory, Portugal. 1
The western Iberian margin marks the northern boundary of the North Atlantic's eastern boundary upwelling system. Nowadays, upwelling along this margin occurs mainly during the period from May to late September/ early October. Previous studies have shown that increased trade wind strength during the last glacial maximum (ca. 21±2 ka ago) led to enhanced upwelling related productivity along the Portuguese and Northwest African margins. Here we present export productivity reconstructions for the last 50 ka (ka = kilo/ thousand ano/ years) along a core transect from 40.6°N to 35.9°N with particular focus on productivity responses to abrupt climate changes between 15 and 50 ka. Core MD95-2040 off Porto and cores MD952041 and MD01-2444 off Sines monitor changes in the upwelling filaments in their region, while core MD992339 is located in the oligotrophic waters of the central Gulf of Cadiz. Export productivity estimates for the 4 deep-sea cores were based on the respective planktonic foraminifera fauna and calculated with a modern analog transfer function (SIMMAX). During glacial warm periods like the Greenland (Dansgaard-Oeschger) interstadials, when climatic conditions differed less from modern ones than during the cold periods, upwelling occurred off Porto and off Sines. In general, the modern gradient in export productivity, with higher values in the north, also existed and absolute values were either in the modern range or slightly higher. Exceptions are Greenland interstadials 7 (~ 35 ka) and 5 (~ 32 ka), when the filament off Sines reached peak values of >250 gC/m2 yr. In the central Gulf of Cadiz, interstadial periods were associated with productivity minima. Glacial export productivity values were, however, 20 gC/m2 yr higher than the more recent ones indicating that glacial nutrient levels were higher than modern ones. During the glacial cold periods – the Greenland stadials and Heinrich events – subpolar surface waters advanced as far south as the Gulf of Cadiz, carrying melting icebergs with them during Heinrich events. Off Porto the cold and fresher surface waters during Heinrich events hampered upwelling resulting in the lowest export productivity values of the last 50 ka. The less cold stadial events were also associated with lower productivity. Off Sines the signal is mixed. E xport productivity was reduced during some stadial and Heinrich events, but not all of them. In the Gulf of Cadiz, on the other hand, export productivity peaked during Heinrich events and Greenland stadials with values similar for both. Values reached >100 gC/m2 yr, more than triple the interstadial or recent productivity and in the range off the Sines filament productivity. Increased productivity in the Gulf of Cadiz seems to be linked to a persistent Strait of the Gibraltar filament and potentially frontal upwelling during Heinrich events.
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PL3
Remote and in situ time-series studies: EBUS as ocean observatories for global change
5 June, 10:15 (PL3 KNS)
Recent trends of primary productivity in upwelling systems in a global warming context H. Demarcq Institut de Recherche pour le Développement, Centre de Recherche Halieutique, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected]
Ten years of SeaWiFS data, and to a less extent 8 years of CZCS data, have allowed for the first time, an analysis of the trends and changes in the seasonal dynamics of the primary production (PP) in all the major upwelling areas, based on surface chlorophyll a concentrations. In a context of a slight overall decrease of the primary production (PP) observed from space in the last decade at a global scale, it appears that the PP in upwelling areas significantly increase, and very rarely decrease, with a large range of amplitude between systems. The Peru and California regions display the strongest increase and the Benguela system the weakest. This general pattern is rarely seasonally homogeneous and in most regions shows higher increases in summer than in winter. The observed trends seems to be due to a combination of factors, generally to an increase of the trade winds in most regions and secondarily to significant changes in the upwelling seasonality, directly impacting the PP. More surprising, it is shown that the observed changes in the PP are of different signs according to the average level of upwelling intensity in the area concerned. Particularly, some regions of strong average upwelling become less productive when subjected to stronger upwelling favourable trade winds (case of the southern Benguela). Similarly, other regions of strong and sustained upwelling (as the Canary central region and the Northern Benguela), where the upwelling intensity slightly decreases, become more productive. Alternatively, in the Peru and California system, the observed increase of the upwelling activity leads to a higher level of productivity. It seems that an increase of the upwelling intensity is beneficial to the PP up to a certain level but detrimental thereafter, when the wind induced turbulence becomes a limiting factor to an optimal growth of the planktonic cells, following a pattern already observed in the spatial dimension. The frequency of extreme events appears to be higher in regions impacted by El-Niño like events and the overall variability generally increase during the period of observation. Taking advantage of the spatial dimension of the satellite data, changes are also observed in the offshore extent of the upwelling, regardless of the trend in the PP, probably following changes in the spatial structure of the wind field. The observed trends in the seasonal amplitude of the PP are discussed in terms of potential impact on the productivity and their contribution to the global carbon cycle.
5 June, 10:45 (PL3 OP1)
Comparisons of chlorophyll interannual variability between the Humboldt and California Current systems A. Thomas and P. Brickley School of Marine Sciences, University of Maine, 104 COAS Admin Bldg, Orono, 04469, USA. Email:
[email protected]
Large-scale variability in interannual patterns of chlorophyll are compared between the two Pacific eastern boundary current upwelling systems, the California Current (CCS) and the Humboldt Current (HCS) using 10 years of daily SeaWiFS satellite ocean color data at 4km resolution. These data are composited to monthly means to quantify seasonal and interannual variability. Empirical orthogonal decompositions extract the dominant coherent signals. In both systems, the strongest signals in the time series are large negative anomalies during the 1997-98 El Niño period, strongest off Peru in the HCS during southern hemisphere summer and off Oregon and Washington in the CCS during fall and spring. Thereafter, the CCS shows stronger interannual variability than the HCS. Strong signals in the CCS are dominated by large positive anomalies in 2002 and 2006, and negative anomalies at the higher latitudes in early 2005. The second mode of the EOF shows a separation in the phasing of dominant anomaly patterns off central Oregon, a location which separates the relatively wide shelf to the north from the relatively narrow shelf 74
Eastern Boundary Upwelling Ecosystems Symposium to the south, and a region where the alongshore coastal jet created during the upwelling season first separates from shore. The space patterns in this mode are strongest off the Washington coast and off central California. In the HCS, anomalies after the El Niño are relatively weak, but strongest during a weak summer upwelling season in 1999-2000 off Peru and central Chile. Space patterns show the dominance of Peru and central Chile in system chlorophyll variability and an out of phase variability at latitudes > 37S off southern Chile. Using 100km cross-shelf chlorophyll means that sample the main upwelling region at each latitude, dominant anomaly time series are compared first to local wind forcing and concurrent signals in satellite-measured dynamic height. The latter are dominated by the ENSO signals of 1997-98. We then compare chlorophyll variability in each system to basin scale climate indices such as the PDO, MEI and NPGO to present the degree to which, and the latitudes across which, these signals are correlated with chlorophyll patterns.
5 June, 11:00 (PL3 OP2)
Seasonal and inter-annual variability in phytoplankton size classes and primary production in eastern boundary upwelling systems N.J. Hardman-Mountford, T. Hirata and J. Aiken Centre for observation of Air-Sea Interactions & Fluxes (CASIX), Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, United Kingdom. Email:
[email protected]
Eastern boundary upwelling systems are known for their high primary production, related to the high availability of nutrients and light. Using novel remote sensing algorithms, we compare the distribution of phytoplankton size classes (micro, nano, pico) for these regions, their relationship to upwelling strength (from SST-based upwelling indices) and their contribution to primary production over seasonal and interannual time scales. The results of this study have important implications for evaluating the likelihood of shifts in the size distribution of phytoplankton communities with climate-related changes in upwelling strength, with feedbacks on biogenic gas exchange, trophic status and fisheries potential.
5 June, 11:15 (PL3 OP3)
Canary Current upwelling: more or less? E.D. Barton1 and C. Roy2 1 2
Departamento de Oceanografía, Instituto Investigaciones Marinas, Eduardo Cabello 6, Vigo 36208, Spain. Email:
[email protected] Laboratoire de Physique des Océans, France.
It has been proposed that coastal upwelling in the four major eastern boundary current systems will be intensified as a consequence of global warming. Recent research has suggested a significant increase of upwelling intensity off Northwest Africa. Evidence is based largely on the derivation of proxy sea surface temperatures from isotope analysis of two sediment cores recovered off Cape Ghir, Morocco. An accelerating decrease in excess of 1ºC over the last century was concluded for near surface temperature near the Cape. Support for this conclusion was found in an increase in Bakun's upwelling index for the latitude of the Cape. We examine the evidence for a general intensification of upwelling within the whole Canary current upwelling system. Using measured wind data from the WMO meteorological station network, we find no evidence of a coherent wind intensification at the scale off Northwest Africa. We find that Bakun’s pressure derived upwelling index, calculated most reliably over the last 50 years, indicates a decrease in upwelling strength at all latitudes from 15º to 43ºN in the North Atlantic Upwelling region, except in the vicinity of Cape Ghir. Surface temperature records from ships-of-opportunity since 1956 (COADS data set) and also from the Reynolds et al. combined satellite-in situ data set starting in 1981 show a significant and correlated increase at all latitudes in the region, including in the area around Cape Ghir. Moreover, sea surface temperatures measured at points on the Portuguese coast since 1960 also show a significant warming. We conclude that in general upwelling intensity off Northwest Africa is decreasing and that any intensification off Cape Ghir must be explained by localized processes. 75
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 11:30 (PL3 OP4)
Sea surface cooling index derived from satellites images in upwelling areas: the case of the Moroccan coastal upwelling A. Benazzouz1, H. Demarcq2, K. Hilmi1, A. Orbi1, A. Atillah3, A. Makaoui1 and J. Larissi1 Institut National de Recherche Halieutique, 2 Rue Tiznit Casablanca, Casablanca 20100, Morocco. Email:
[email protected] IRD, Sète, France. 3 Centre Royal de Télédétection Spatiale, Rabat, Morocco. 1 2
Coastal upwellings are complex biological and physical phenomena, characterised by important fluctuations in time and space. Remote sensing data provides an adequate way to monitor this dynamic. The main objective is to make available to scientists a synthetic spatio-temporal information based on standard operational products and allowing an easy to use estimate of the upwelling activity. In this work spatial Sea Surface Temperature (SST) data from the NOAA/AVHRR and Modis/aqua sensors was used. The main product developed is a thermal upwelling intensity index derived from the SST field that is firstly based on the upwelling presence or absence and that quantifies its intensity according the cross-shore SST gradient. The results are validated by means of Ekman index calculated from wind data of two meteorological coastal stations of the southern Moroccan coast, Laayoun and Dakhla. Systematic spatial use of data from the QuikSCAT scatterometer also shows that our upwelling index provides a useful complementary observation of the upwelling spatial structure and surface intensity that a wind field alone is unable to provide. In this way, an upwelling index data set is built, covering 23 years (1985-2007) of weekly data. The spatial and temporal dynamic of the upwelling along the atlantic Moroccan coasts (21-36°N) is described as well as the potential impact of the upwelling intensity on the pelagic stocks in the region. A classification into four characteristic areas is made according the intensity of the upwelling index which regularly increases from South to North, according to the trade wind gradient. The zonal seasonality of the index, described from the climatology of the whole data series, is always marked with a maximum of seasonality between 26 and 32° of latitude North and a minimum of seasonality in the South, where the upwelling is strong and quasi permanent. The inter-annual variability of the index is very consistent in space and do not show any significant temporal trend during the study period except a strong negative anomaly between 1995 and 1997, as a consequence of a strong decrease in the trade winds. This event coincides with a strong negative anomaly on the pelagic fisheries, specially the sardine fishery, both in term of catches and acoustic estimated biomass. Changes in the productivity of sardine observed for the same period suggest that there was a response of the ecosystem to these changes. An SST-based upwelling index therefore provides useful information on the upwelling dynamic to explore the environmental impacts on pelagic stocks in the region.
5 June, 11:45 (PL3 OP5)
Evolution of oceanographic conditions in the permanent upwelling region off the northwest Africa 1995-2006, with consequences to distribution of pelagic stocks M. Ostrowski1, P. Chernyshov2, I. Gleza2, K. Hilmi3, S. Kifani3, J.O. Krakstad1, A. Makaoui3, F. Mélin4 and A. Orbi3 Institute of Marine Research, Postboks 1870 Nordnes, 5817 Bergen, Norway. Email:
[email protected] Atlantic Research Institute of Fisheries and Oceanography (AtlantNIRO), Russia. 3 Institut National de Recherche Halieutique, Morocco. 4 E.C. Joint Research Centre Institute for Environment and Sustainability, Italy. 1 2
Combined oceanographic sections from the AlantNIRO and Nansen Programme surveys in the perennial upwelling region off Western Sahara (1994-2006) are examined for geographic zonation of upwelling structure and sources of upwelled coastal water. This is supplemented by an analysis of satellite data (AVHRR, ocean color, altimetry and scatterometer-derived winds) in order to determine timing and spatial extends of the events observed in shipborne data. The oceanographic sections highlight a significant alongshore variation in the upwelling structure. To the north of 22ºN active upwelling appears to be restricted to a narrow band near the shelf break whereas the shallow waters are well mixed, presumably under a direct influence of wind and bottom inducted turbulence. In the southern area, the observations 76
Eastern Boundary Upwelling Ecosystems Symposium confirm the classical upwelling scenario with the offshore Ekman transport at the surface; return flow near the bottom and poleward transport at the shelf break. The source of the upwelled water masses vary also alongshore, from relatively nutrient poor North Atlantic Central Water (NACW) in the north to nutrient rich South Atlantic Central Water (SACW) in the south. NACW enters the region with the Canary Current and occupies the upper part of the water column whereas SACW intrudes underneath in the opposite direction, occupies the lower portion of the water column and is confined to the shelf-break area. The strength of the SACW penetrations varies strongly with the season. It is weakest during spring, strongest during fall. The higher nutrient concentrations in SACW, suggests higher primary productivity in the upwelled waters in the southern part, despite a uniform upwelling favourable wind forcing alongshore the entire region. This is indeed evidenced in remotely sensed chlorophyll data showing an increase in concentrations to the south of 22ºN with a maximum during fall. From the combined oceanographic and remotely sensed evidence, we suggest two types of warm events experienced during the observational period: the events of the equatorial origin, which affect mainly the strength and extend of the northward SACW penetrations (e.g. 2002) and those linked to the negative NAO phase, causing upwelling relaxation and warming of coastal waters over the entire region (e.g. 1996 and 1997). The discussion relates impacts of these events on changing zoogeography of sardines (Sardine pilchardus) and sardinellas (Sardinella aurita), species dominating pelagic stocks in the region.
5 June, 12:00 (PL3 OP6)
Interannual to decadal variability of SST off the coast of Peru: connection with the equatorial Kelvin wave S. Purca1, B. Dewitte2, B. Giese3, J. Vazquez4 and D. Correa1 Instituto del Mar del Peru, Esquina Gamarra y Gral. Valle s/n. Chucuito. Callao, Peru. Email:
[email protected] Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, France. 3 A&M, University College Station, USA. 4 National Aeronautics and Space Administration (NASA), USA. 1 2
The Peruvian coast behaves as an extension of the equatorial wave guide at a variety of timescales, from intraseasonal to interannual. Although the interannual variability of SST along the coast exhibits the largest amplitude, decadal fluctuations are significant and impact the fish industry in the region. The reason for such decadal variability is not completely known and remains an issue of debate. In this study, the link between equatorial variability and the regional SST variability (3°S-18°S; coast to 100 km off shore) is investigated by means of historical satellite data and Reanalysis products (such as the pathfinder 4km data sets); as a first step the in situ data are confronted to the satellite data over the overlapping period (1985-2006), which reveals a good agreement between both data sets for the dominant statistics variability modes. The ultra-high-resolution (1 km) satellite data available from the Global Ocean Data Assimilation Experiment (GODAE) High Resolution Sea Surface Temperature Pilot Project (GHRSST-PP) of the satellite allows for documenting the SST front associated with the narrowly extended coastal upwelling, which is not the case for the historical data from the IMARPE cruises (1950-2006). Statistical analysis of the satellite data combined with the in situ data suggests that this front experienced cross-shore displacement at decadal timescales, which provides an index of upwelling variability at low frequency. Second, the equatorial Kelvin waves are estimated from a modal decomposition of the SODA Reanalysis and indices of low frequency Kelvin wave activity are derived with a focus on the intraseasonal Kelvin wave and its modulation at low frequency. The analysis indicates that those indices are significantly correlated to the interannual and decadal modes of SST along the coast, which suggests that the high-frequency equatorial variability translate to the decadal mode along the coast of Peru. Another contribution to the decadal variability along the coast appears to be related to the asymmetry of the seasonal to interannual variability along the coast resulting from the asymmetrical equatorial forcing. Our results illustrate the specificity of the response of the Peru coastal system to the equatorial Kelvin waves and the importance of scale interactions associated to this forcing. 77
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 12:15 (PL3 OP7)
Long-term trends in spiciness, dissolved oxygen, and inorganic nutrients in the southern California current system S. Bograd1, C. Castro2, C. Collins3 and F. Chavez4 1
NOAA, Southwest Fisheries Science Center, Environmental Research Division, Pacific Grove, CA, 93950-2097, USA. Email: steven.
[email protected]
2
Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Cientificas, Spain.
3
Department of Oceanography, Naval Postgraduate School, USA.
4
Monterey Bay Aquarium Research Institute, USA.
We use historical hydrographic data from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program to explore the temporal variability of physical and chemical properties of slope waters impacted by the California Undercurrent (CUC) over the period 1984-2006. The upper water column has experienced a strong warming trend, and is greatly impacted by El Niño events. At the depth of the CUC, waters have become progressively warmer, saltier, and lower in oxygen content. There have also been increasing trends in nitrate and phosphate in CUC waters, although at different rates, leading to highly significant declines in the NO3:PO4 and SiO4:NO3 ratios. Variability in CUC net transport and source water properties are the most likely causes of the observed trends. Significant changes in the oxygen content and nutrient composition of CUC waters, which are upwelled upstream, could have important implications for the California Current ecosystem. We also examine the CUC trends in the context of decadal variability in water properties throughout the southern California Current system, based on the CalCOFI 1949-2006 series of temperature, salinity, and dissolved oxygen measurements.
5 June, 12:30 (PL3 OP8)
Biological action centers as oases within eastern boundary upwelling ecosytems S. Lluch-Cota1, D. Lluch-Belda2, M. Morales-Zárate1 and H. Herrera-Cervantes2 1
Fisheries Ecology Program, Mar Bermejo 128 Col Playa palo de Santa Rita, La Paz, BCS, 23090, Mexico. Email:
[email protected]
2
Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Mexico.
A decade ago, an observation resulted from a series of workshops about variations in the abundance and distribution of small pelagic fishes in eastern boundary currents systems. It was noted that within these highly productive upwelling ecosystems, there are smaller areas where biological activity is particularly high, dubbed "Biological Action Centers" or BAC. They appear to be fixed in space, tied to coastal features, and tend to show little seasonal variation in their level of productivity. They are often the locus of spawning of small pelagics and other species and of fisheries related to the aggregations of commercial species, and they act as refugees for these populations during interdecadal adverse climate regimes. BAC where perceived as good places to study interactions between ecosystem and climate variations and to examine the mechanisms of such interactions, and an option to optimize monitoring of ecosystem changes. This last was attractive to the Living Marine Resource Panel of the Global Ocean Observing System, who proposed a pilot study to investigate BAC and their ecosystem role, to identify existing BAC, to determine the extent to which observations in BAC could be extrapolated to surrounding areas, and to investigate the extent to which BAC provide an indication of climate change. Even when no formal project was ever conducted, the research approach was adopted by several scientists, particularly in the Mexican Pacific. In this contribution we review what’s been done on the topic and what needs to be approached in the next few years, we link to similar approaches explored by other groups and for other kind of ecosystems, and we take a first step to extend the North Pacific experience to the rest of the eastern boundary upwelling ecosytems. 78
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 12:45 (PL3 OP9)
Interdecadal to Centennial variability of paleoproductivity and redox conditions in the Peruvian continental margin during the last two millennia A. Sifeddine1, D. Gutiérrez2, M. Gurgel1, M. García1, L. Ortlieb1, M. Boussafir1, F. Velazco2, H. Boucher1, S. Caquineau1 and J. Valdés3 IRD, Paleotropique-DME, 32 Avenue Henri Varagnat, Bondy, Ile de France, 93143, France. Email:
[email protected] Instituto del Mar del Peru, Peru. 3 Laboratory of Sedimentology and Paleoenvironments (LASPAL), Chile. 1 2
The Peruvian continental margin sediments are normally subjected to bottom water suboxic conditions as well as to high loadings of organic matter from the surface waters. However oceanic variability at different temporal scales modulate the intensity of the particle flux and water column oxygenation, which are expected to influence the inventories and downcore distributions of organic matter and trace metals. The main goal of this study is to explore the interdecadal to centennial changes in paleo-redox conditions of the Peruvian margin sediments, as inferred by the downcore variability of inorganic geochemical parameters and try to interpret them in relation to variations in redox-conditions linked to organic particle flux. To identify longterm variations in productivity and oxygenation, we examine: 1) TOC content, which depicts the abundance of organic matter and inferred productivity, 2) an Oxygen Index (OI), which is related to indices of organic matter preservation and aerobic oxidation, and 3) redox-sensitive metals (e.g. Mo and Cd) used to evaluate the paleo-redox depositional conditions. Additionally, the mineralogical composition of sediment cores can provide relevant information of past environmental and climate conditions by recording the terrigenous input from the continent as related to erosion processes, aeolian transport, runoff, and deposition on to the continental margin. Thirteen AMS 14C dates on total organic matter in the Callao core allow us to reconstruct a history of sediment accumulation over the past 13 ka BP. The distribution of radiocarbon ages shows the occurrence of two intervals of continuous sedimentation rate, between 0 and 245 cm depth (0 to ~3000 14C yr BP) and 245 and 550 cm depth (~8000 to 13 000 14C yr BP) separated by a sedimentation gap (8000 to 3000 14C yr BP). Callao sediments are very rich in organic carbon (TOC), averaging about 7% and reaching up to 11%. The minimum content of organic is found around 230 cm sediment depth (2-3%). The sedimentary organic matter presents in general high values of Hydrogen Index HI (values of 360 to 580, mean 460), and low values of Oxygen Index OI (values 70 to 180, mean 100), indicating a well-preserved organic matter. The downcore variations of Mo and Cd show similar patterns varying respectively around 52 and 60 mg/kg. Interdecadal variability seems to be the mode that controls the productivity and the paleo-redox conditions, probably due to changes in upwelling intensity and expansion/ contraction of the Oxygen Minimum Zone (OMZ). From 1500 to 500 14C yr cal BP, a centennial climatic regime reflected higher terrigenous input and probably favored OMZ ventilation and reduced productivity within the Humboldt Current system.
5 June, 13:00 (PL3 OP10)
The last deglaciation paleoproductivity and paleoclimate off southern Chile: a diatom (accumulation rates, assemblages and transfer functions) view F. Abrantes1, C. Lopes1,2 and E. Amigoni1,3 Departamento de Geologia Marinha, INETInovação, Estrada da Portela, Aptdo 7586, Amadora, Lisboa, 2721-866, Portugal. Email:
[email protected] 2 Centre for Marine and Environmental Research, Portugal. 3 University of Genova, Italy. 1
Diatom based transfer functions have been generated for sea surface temperature (SST), primary productivity (PP) and nutrient concentration using canonical correspondence analysis (CCA) and weighted averaging (WA) techniques on data from 232 SE Pacific surface sediment samples. These transfer functions were applied to diatom assemblage composition for site 1233, recovered off Southern Chile (41 ºS, 74.45 ºW, 837 m) during ODP Leg 202, and for the time interval between 23 and 8 Cal kyr B.P. Furthermore, those diatom reconstructions were compared to alkanone derived SST, planktonic foraminiferal δ18O as well as diatom assemblages and Diatom and Phytoliths Accumulation Rates (DAR & PhAR). At present, site 1233 79
Eastern Boundary Upwelling Ecosystems Symposium is located in an area where the ocean surface forcing is dominated by strong poleward winds and heavy precipitation that generates a tongue of low-salinity water that spreads northward from the fjord region (≈ 43ºS). Oceanic circulation is dominated by the splitting of the West Wind Drift (WWD) into the Peru Current (PC) and the Cape Horn Current (CHC). Primary productivity in the region increases in winter/ spring possibly associated to river input of nutrients and/or micronutrients. During the 22-8 Cal kyr B.P. time interval diatoms show centennial to millennial variability, and marine DAR increases as alkenone SST decreases and δ18O becomes heavier. Highest DAR (108 valves/cm2 kyr) occurs between 20 and 22 Cal kyr BP, and the diatom assemblage is dominated by the genus Chaetoceros, which may be interpreted to reflect an intensification of the PC. A new average increase in DAR (to values ≈ 8*107 valves/cm2 kyr) is noted from 11 to 9 Cal kyr B.P. followed by a sharp decrease to a minimum centered at about 8.4 Cal kyr B.P. Oceanic warm water forms reach maximum AR between 10 and 9 Cal kyr B.P. indicating a possible strong southward penetration of relatively warm subtropical waters or the poleward flowing undercurrent in the earliest Holocene. The downcore comparison of the diatom and alkenone derived SST records reveals: (1) similar trends but a temperature difference of about 4ºC between 23 and 16.4 Cal kyr BP; (2) similar temperatures between12.2 and 9 Cal kyr BP; (3) a major difference between 15.8 and 14.8 Cal kyr BP, with diatom derived SST indicating a maximum 7ºC higher than alkenone derived SST. This difference will be furthermore investigated with a complementary study of the deglaciation period on ODP sites 1237 and 1240.
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PL3 Posters Poster: PL3 P1
The seasonal upwelling and primary production of the Gulf of Panama: ENSO implications J. Agujetas1 and G. Mitchelson-Jacob2 1 2
School of Life Sciences, Heriot-Watt University/STRI, 5/8 Waverley Park, Edinburgh, EH8 8EW, United Kingdom. Email:
[email protected] School of Ocean Sciences, University of Wales, United Kingdom.
The Gulf of Panama is an aquatic system associated with seasonal wind-driven mixing and upwelling of nutrient-rich waters. These processes are affected by El Niño Southern Oscillation events, which cause high interannual variability in the area of study. SeaWiFS and AVHRR images of chlorophyll a concentration, photosynthetically available radiation and sea surface temperature, from January 1998 to June 2004, were used to study the upwelling and to calculate the changes in the local net primary production (NPP). The upwelling conditions start in January each year and finish at the end of April. From the AVHRR SST monthly composites for February and March the plume of cold water associated with the wind jet appears to be continuous along the Gulf of Panama in most years. In March the centre of the plume reaches temperatures of approximately 21°C and it is frequently associated with high chlorophyll a concentrations (above 10 mg m-3). Panama Bay and Las Perlas Islands, in the north and centre of the Gulf, are the two zones that achieve the highest chlorophyll a concentrations during the upwelling months. Additionally, these zones are the most productive with Vertically Generalised Production Model estimated daily NPP often above 6 gC m-2 during the months of February and March each year. Production under “neutral” conditions, estimated using satellite data and the vertically generalised production model, accounts for approximately 473 gC m-2 y, which is around 2.5 times the annual production noted in previous works. During the dry season, from January to April, the NPP is slightly more than the half of the total annual production; the highest values being those recorded for the two years 2000 and 2001, with annual NPP of 566 and 521 gC m-2 y-1 respectively, when the dry season was under strong La Niña conditions. However, physical conditions and biological production in the Gulf of Panama seem to exhibit lagged responses to the onset of El Niño Southern Oscillation episodes.
Poster: PL3 P2
Seasonal and interannual variability of satellite–derived net primary and new production in shelf and slope waters of the NW Iberian upwelling system over the period 1998– 2007 X.A. Álvarez–Salgado1, S. Groom2, F. Figueiras1, O. Espinoza1, J. Otero1 and B. Taylor2 1 2
CSIC, Instituto de Investigaciones Marinas, Eduardo Cabello 6, 36208 Vigo, Spain. Email:
[email protected] Plymouth Marine Laboratory, United Kingdom.
Daily satellite–derived net primary (NPP) and new (NP) production rates, calibrated with in situ observations, have been used to study the seasonal and interannual variability of the productivity of the continental shelf and the adjacent slope waters of the NW Iberian Peninsula from 42ºN to 43ºN. Considering the whole study period, 1998 to 2005, the average shelf NPP, 310 g C m–2 y–1, was 75% higher than in the adjacent slope waters. The excess production over the shelf, 130 g C m–2 y–1, was due to the excess of upwelled nutrients and, therefore, can be considered as the NP of this ecosystem. A Fourier analysis of the time series revealed that: i) at the seasonal time scale, the slope NPP maximum ( 0.80 g C m–2 d–1) occurred early in June, whereas over the shelf ( 1.35 g C m–2 d–1) it was delayed about one month, and the NP maximum (0.60 g C m–2 d–1) occurred early in August, coinciding with the seasonal maximum of upwelling; and ii) at the interannual time scale, the shelf NPP decreased by 10±5% over the study period (R2 = 0.40, n = 8, p < 0.05), essentially during the spring and summer months. The same trend was observed for the slope NPP, whereas the shelf NP did not change significantly over the study period. 81
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Poster: PL3 P3
High resolution biomarker record of upwelling and productivity changes over the last 200 years off central Peru I. Bouloubassi1, L. Méjanelle1, A. Sifeddine2, D. Gutierrez3, F. Velazco3 and L. Ortlieb2 LOCEAN, UMR 7159 CNRS/UPMC/IRD, IPSL, 4 place Jussieu, Paris 75005, France. Email:
[email protected] IRD-PALEOTROPIQUE, France. 3 Instituto del Mar del Peru, Peru. 1 2
Reconstructions of past climate and ocean variability and of the response of marine ecosystems on interannual to centennial time scales (extending thus the instrumental records) from high resolution marine archives are critical in order to provide a better process-oriented understanding of climate/ocean dynamics and its links with ecosystem change. We have examined a series of molecular organic proxies (biomarkers) and combined them with complementary mineralogical and elemental organic data in a sediment core collected in the central Peruvian margin off Pisco (14°20’S, 299m), downstream of the main upwelling centre in order to reconstruct climatic, environmental and productivity changes over the last 200 years. Reconstructed SSTs, based on an alkenone unsaturation index (Uk37), showed conspicuous positive/negative excursions in-line with past El Niño/El Niña events. A prominent cooling trend since the late 18th century is clearly evidenced and likely reflects a progressive intensification of the upwelling regime. Examination of the SST proxy records over the instrumental period (last decades) further supports this trend. The amounts and relative abundance of lipid biomarkers used as proxies for major phytoplankton groups, such as alkenones (for coccolithophorids), specific sterols (for diatoms and dinoflagellates) record changes in the productivity patterns as a response to changing upwelling intensity and to ENSO phases. Furthermore, the biomarker proxies allow identification of short- and long-term modifications of phytoplankton community structure, most likely reflecting adjustments to dynamic and chemical surface ocean.
Poster: PL3 P4
Satellite oceanic observatory atlas part I: historical data D. Dagorne1, H. Demarcq2 and L. Drapeau2 1 2
IRD – US191, Technopole Brest, Iroise BP 70 – 29280 Plouzané, France. Email:
[email protected] IRD – UR ECO-UP, France.
Satellites imagery provides the synoptic views needed to study ecosystem dynamics occurring at regional and global scales. High temporal resolutions, long time series of images and high spatial resolution of the new sensors have contributed to make satellite images key elements for monitoring and characterising marine ecosystems. Use of these products by end users communities has not reached its full potential due issues of accessibility. To improve the diffusion of multiple satellite image datasets, we processed, structured, archived, and distributed these datasets, via an interactive website for “end users” at monthly and weekly resolutions. Measurement of oceanic surface parameters (SST, “ocean colour”, wind stress, altimetry) from several providers are made available for viewing and downloading, consisting of: -“standardised” netCDF data files extraction with temporal and spatial extraction criteria for local archives and re-use user software; - production of “QuickLook” image representation of multi-temporal series; - WEB browsing with database multi criteria queries: temporal and spatial resolution – coverage, with an intuitive navigation (area, parameter, source, time step); The four eastern boundary upwelling ecosystems are the main target areas within the scope of many projects (comparative atlas, model validations, climatological trend, meso-scale research (eddies, filament), etc) with studies at regional and local areas and over a long term duration. Parameters involved include: SSTs from “Reynolds optimal interpolation (1 deg-1982), micro-wave (1/4deg/1998) and Infra-Red sensors (9/4km-1985); Chlorophyll (CHL) standard products from “ocean colour” data obtained from leaving water radiance in visible channels; Wind modulus and direction with ERS 1-2 (1 deg – 1992) and QuickScat (½ - ¼ deg – 2000); 82
Eastern Boundary Upwelling Ecosystems Symposium Sea Level Anomaly/Sea Surface Height (SLA/SSH) from altimetry programs (1/3 deg -1992) with derived currents; Applications from extracted time series on the four upwelling systems include high level products such as anomalies, synthetic indexes on shelf showing spatio-temporal evolution of upwelling dynamics or long term trend analysis for climate impact.
Poster: PL3 P5
Satellite oceanic observatory atlaspart II: near real time data D. Dagorne1, H. Demarcq2 and L. Drapeau2 1 2
IRD – US191, Technopole Brest, Iroise BP 70 – 29280 Plouzané, France. Email:
[email protected] IRD, UR ECO-UP, France.
From January 2007, IRD has produced a daily spatial extraction of “Near Real Time (NRT)” (i.e. access at day 1) satellite products available from several operational or scientific agencies and programs: NOAA, NASA “ocean colour”, EUMETSAT SAF-ocean, GHRSST-PP, etc. Its aim is to facilitate the use and integration of remote sensing products in scientific projects and studies. This is an attempt to promote remote sensed ocean measurement into operational data products for end-user communities, where the potential for use of this information has not been fully reached. Our NRT application provides an operational survey of main oceanic features at high spatial resolution and temporal revisiting periods for areas in developing countries, in the three oceans, mainly for research requirements. Three of the upwelling systems are daily monitored at regional or local scales. Using the daily downloaded files from providers, each with its own distributing formats, we developed a uniform access from a “standardized” extraction file and a WEB access for available parameters. Available parameters include: - SST(s) from infra-red sensor from polar orbiter with global coverage or geosynchronous using level 3 resolution (4-5 / 10 km) but with high cloud cover restrictions. In complement SST from Micro-wave measurement give an “all weather” information but at low resolution (1/4 deg) and outside of coastal areas; - Chlorophyll (and simultaneous SST) from Visible MODIS sensors (4 km) with the same restriction due to cloud cover and atmospherics constraints (sun glint, aerosols,); - Wind from ‘Quick Scat” (1/4 deg) Polar satellite provide instantaneous viewing twice a day (Day/Night pass) – only once a day for “colour” parameters. A temporal composite synthesis of 3 days is used to maximise areas without clouds. The same processing is used for high temporal resolution from geosynchronous (30 mn-1H) to produce 12 H composite (D/N) products. In some case (interesting feature like HAB, oceanographic cruise), with low cloud coverage, a high resolution (1 km) level 2 data, SST or “ocean colour” can be used due to global coverage of some of these data. We plan to integrate access to simulation prevision model results.
Poster: PL3 P6
A novel experimental approach for determining CO2 and O2 fluxes in the tropical eastern North Atlantic – experimental setup and preliminary results B. Fiedler and A. Körtzinger Leibniz-Institute of Marine Sciences (IFM-GEOMAR), Marine Biogeochemistry, Düsternbrooker Weg 20, 24105 Kiel, Germany. Email:
[email protected]
Biogeochemical cycles in upwelled water masses are subject to a broad range of dynamical impacts. These parts of the ocean are also known as “hot spots” particularly for the gas exchange between the surface ocean and the lower atmosphere with significant dimensions. In order to investigate the spatial and temporal variability (daily, seasonal or inter-annual) of CO2 and O2 air-sea fluxes and their underlying processes, a dense network of observations is required. For this purpose, the Tropical Eastern North Atlantic Time-Series Observatory (TENATSO) at Cape Verde (Sao Vicente) provides a unique infrastructure. Consisting of an atmospheric and oceanic observation site, 83
Eastern Boundary Upwelling Ecosystems Symposium located downwind of the Mauritanian upwelling, this observatory is directly influenced by the upwelling region off the Mauritanian coast. The data obtained are very useful for investigations of biological productivity, air-sea interactions of greenhouse gases and dust impacts. Available data (CTD, nutrients, O2, DIC, Alkalinity, DOC, and Chlorophyll) were obtained by a long-term mooring combined with a regular sampling programme (at least monthly) with a small research vessel at the oceanic site. To expand these capabilities, a novel “virtual mooring” approach for high resolution measurements is pursued based on two modified NEMO profiling floats (Optimare Sensorsysteme GmbH, Bremerhaven/Germany). These Profiling Floats were equipped for the first time with oxygen (Model 3830 Optode, Aanderaa Instruments, Bergen/ Norway) and pCO2 sensors (PSI-CO2-Pro, Pro Oceanus Sensors Inc., Halifax, Canada) for collecting daily depth profiles (0-200 m) in the vicinity of the oceanic site. Data access and remote control is provided through iridium satellite telemetry and recalibration and –deployment are carried out every 1-3 month. This time series started in spring 2008 as part of the German SOPRAN project (Surface Ocean Processes in the ANthropocene). Here we will present the approach as well as some preliminary results of the test phase and the regular ship-based sampling program to underline the feasibility of this innovative in situ and real-time approach.
Poster: PL3 P7
Regimen shift in the Canary Current system J. Gómez and S. Hernández-León Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain. Email:
[email protected]
Sea Surface Temperature anomalies data were analysed in order to study their variability in the Canary Current system during the last three decades. The analysis of six time series homogenously distributed within the study area (from 10 to 40oN and from 15 to 20oW) shows a regimen shift in the area as observed from sea surface temperature anomalies in the middle of the nineties (1994 to 1996), where two periods were clearly different from 1981 through 1994 and from 1996 to 2007. The second period was significantly warmer than the former (one way ANOVA), whereas Sea Surface Temperature anomalies were relatively stable during both periods. The reconstructed long-term trend of mesozooplankton from historical data in the area of the Canary Current around the Canary Islands will be showed and the results discussed in relation to the changes in small pelagic and benthic fishes around the archipelago.
Poster: PL3 P8
Interannual, seasonal and short-term variability of wind-stress along the NW and N Iberian shelf G. González-Nuevo, E. Nogueira, E. Cabal and E. Álvarez IEO, Centro Oceanográfico Gijón, Avda Principe de Asturias 70 bis, Gijón, Asturias, 33212, Spain. Email:
[email protected]
The NW and N Iberian Peninsula, which is part of the Canary eastern boundary upwelling system (CanaryEBUS), is subject to seasonal upwelling processes that exert a major influence on ecosystem processes in this region. However, due to the different orientation of the coast along this eastern boundary region, wind-driven upwelling is forced by zonal winds in the westernmost part of this shelf and by meridional winds in the Cantabrian Sea. This may cause important differences in terms of seasonality, frequency and persistence of upwelling pulses, which in turn will affect differentially ecosystem dynamics and functioning along this shelf. In order to get insights on the spatial and temporal variability of wind-driven upwelling along the NW and N Iberian shelf, we have analysed by means of standard time series analysis methods, wind-stress data from the NCEP/NCAR Reanalysis data set at four different locations along this part of the Canary-EBUS. 84
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Poster: PL3 P9
Upwelling index derived from satellite imagery along the West Iberian Coast from 1995-2005 G. King1,3, J. Dias2 and J. Yang3 Dep. Engenharia Geográfica, Geofisica e Energia Fund, FCUL - Instituto de Oceanografia Campo Grande Lisboa, 1749-016 Portugal. Email:
[email protected] 2 Instituto de Oceanografia, Fac. Ciências, Univ. de Lisboa, Portugal. 3 School of Engineering, University of Warwick, United Kingdom. 1
The upwelling along western Iberia has a mainly seasonal character associated with the presence of northerly winds during the summer season. In response to wind-induced coastal surface divergence during summer, cold subsurface waters occupy the nearshore zone along coast and sometimes extends offshore locally as filaments. During winter upwelling episodes are sporadic, have a shorter duration, and are less intense than in summer. Superimposed on this seasonal cycle and probably related to the largescale climatology of the NE Atlantic, interannual and long-term variability of the upwelling off Iberia can be detected in longer time records of upwelling-dependent physical and biological parameters. Due to the complex nature of the upwelling system, many workers have found it useful to construct an “upwelling index” based on the difference in temperature between a position near the coast and the open ocean. Such an index provides a simple and valuable time and space record of the intensity and variability of coastal upwelling and can be used to correlate with physical and biological parameters of the coastal ecosystems. In the work reported here, an upwelling index for the west Iberian coast has been constructed from weekly high resolution (1x1 km) satellite measurements of sea surface temperature (SST) covering the period 1995 – 2005. The data (NOAA-AVHRR MCSST) was obtained from the German Aerospace Center (DLR) and from the satellite receiving station at Instituto de Oceanografia (IO) in the University of Lisbon. Gaps in the data due to clouds or instrument failures were filled using data interpolation based on an empirical orthogonal decomposition method. A space-time map of the upwelling index is obtained from the filled in data as a function of latitude and time. The variability about this average year is studied further by means of an Empirical Orthogonal Function analysis (EOF) on the upwelling index space- time map. The correlation of these results with the North Atlantic Oscillation index (NAO) will be reported.
Poster: PL3 P10
Spatiotemporal variability of four major upwelling systems, 1950-1999 R. Lemos1, M. Juliano2 and B. Sansó3 University of Lisbon Rua Carlos Mardel, 111, 2-B, Lisbon, 1900-120, Portugal. Email:
[email protected] University of the Azores, Portugal. 3 University of California Santa Cruz, USA. 1 2
We consider the problem of fitting a statistical model to 50 years of temperature and salinity records collected in the Canary, Benguela, California and Humboldt current systems. The purpose of the model is to produce an atlas of oceanic properties, including climatological mean fields, estimates of historical trends and a spatiotemporal reconstruction of the anomalies. These products are of interest to climate change and climate variability research, numerical modelling and remote sensing analyses. Our model constructs instantaneous fields prior to averaging them into the climatology, thus giving equal weight to all years in the time frame. It also accounts for non-isotropic and non-stationary space and time dependencies, owing to its use of discrete process convolutions. We use compact support kernels that allow an efficient parallelization of the Markov chain Monte Carlo method used in the estimation of the model parameters. Results are compared with the output of the Simple Ocean Data Assimilation Model. 85
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Poster: PL3 P11
Phytoplankton pigment variability in the northern Canary Current system J. Morales1, A. Thomas2, C. Jimenez1, A.J. Mata1 and L. Marquez1 1 2
IFAPA Centro “Agua del Pino”, P.O. Box 104. 21071 Huelva, Spain. Email:
[email protected] School of Marine Science, University of Maine, USA.
Coastal areas of the northern the Canary Current System (32ºN-44ºN) can be viewed as three main regions: the Iberian Upwelling System (Portuguese - Galician coasts), the Gulf of Cadiz, relatively isolated from wind patterns that dominate the other regions, and the Northern Morocco region, north of the Saharan upwelling system. While phytoplankton variability in the Iberian Upwelling System is relatively well studied, the Gulf of Cadiz has only recently been studied, and Northern Morocco is quite poorly understood. Here we provide a systematic comparative analysis of the three regions as a functional tool for the understanding seasonal and interannual differences using ten years (1997-2007) of daily SeaWiFS satellite ocean color data composited into monthly means. Basic patterns are compared to in situ data collected during a regular monitoring program in the northern sector of the Gulf of Cadiz. Empirical Orthogonal Function (EOF) analysis of the monthly images extracts the dominant patterns of coherent variability in the phytoplankton. The dominant mode (24% of total variance) has maximum values in the coastal areas, strongest off the Galician coast and in the Gulf of Cadiz and minima offshore of the Moroccan coast. Seasonality of this pattern shows maxima in winter (Jan-Mar) and minima in late summer (July-Sept). Second mode (13 % of variance) shows three well-delimited areas: the Galicia - Portugal coast and the coastal area in front of Agadir (both in phase) and out of phase with the area near the Guadiana and Guadalquivir river mouths. The time series suggests that the first two regions (maxima in summer) are associated with regional wind patterns. The third mode (10 % of variance) appears to separate type 1 from type 2 waters, likely explaining variability introduced by suspended material, yellow substance, etc. introduced by runoff. Interannual variability in the dominant mode shows this pattern was strongest in winters of 2001, 2003 and 2005, and weakest in 2000. Time series of cross-shelf chlorophyll distributions (0-40 km) of the three regions show that the Iberian upwelling system follows the classical pattern for the Atlantic temperate regions with a large spring maximum, followed by another small peak early in autumn. Coastal concentrations are highest in the Gulf of Cadiz, with both a broad winter maxima and spring peak and another smaller peak in late autumn. Concentrations are weakest and closest to shore off Northern Morocco, with a prolonged maximum extending from November to April. These patterns suggest a latitudinal displacement of the seasonal maximum of chlorophyll from early winter in the south to late spring in the Portugal/Galicia region with strong river modulation of both the northern Iberian and the Gulf of Cadiz signal.
Poster: PL3 P12
The reconstruction of primary productivity in the Portuguese-margin since the last glacial: preliminary results from a multi-proxy study C N Prabhu1,2, T. Rodrigues2, J.A. Flores3, A.Voelker2 and F. Abrantes2 Centre for Marine and Environmental Research, 289, Porto, 4050-123, Portugal. Email:
[email protected] Department of Marine Geology, INETI, Portugal. 3 Department of Geology, University of Salamanca, Spain. 1 2
The Portuguese margin, as a part of the North Atlantic Ocean, has witnessed strong and abrupt climatic oscillations, like Heinrich events, in the past. The effects of those oscillations on the biogeochemical processes are yet to be deciphered thoroughly. Thus, for understanding the variations in the hydrographic conditions due to climatic oscillations and their influence on the primary productivity triggered by seasonal upwelling in the Portuguese Margin since the last glacial period, a sediment core MD03-2699 raised from the Estremadura Spur (39 N; 10 39 W) has been studied. A multi-proxy approach comprising of planktonic and benthic stable isotopes, planktonic foraminifer and coccolithophore assemblages and alkenones have been employed. Good preservation of coccoliths in all the samples studied rules out the possibility of 86
Eastern Boundary Upwelling Ecosystems Symposium dissolution effect, which was a widespread phenomenon in the glacial oceans. Twenty Coccolithophore species were identified. Among them Gephyrocapsa oceanica, Gephyrocapsa muellerae, Emiliania huxleyi and Calcidiscus leptoporus are the dominant forms. The Uk’37 SST is recorded around 150 C from the bottom upto 160 cm and a SST minimum is observed 150 cm core depth. Further, the SST rises to around 180 C towards the core top. The total alkenone concentration, Emiliania huxleyi (> 4 µm) and F. profunda abundance decrease with increase in SST. Except a peak around 150 cm, while SST is at minimum, the % tetra alkenones shows very little variation throughout the core. Although C. pelagicus abundance was low in most of the samples studied, it shows significant increase when % tetra alkenones, assumed to be an indicator for cold lower salinity surface waters, is maximum. With a precise chronology, these combined data sets should give a better insight into the relation between the hydrography, SST and primary productivity variation.
Poster: PL3 P13
Variation of the chlorophyll a concentration in the Cape Verde region related to SST, wind and geostrophic currents from satellite data V. Ramos1, J. Pérez-Marrero1, O. Llinás1, A. Cianca1 and J. Morales2 1 2
Instituto Canario de Ciencias Marinas, ICCM carretera de Taliarte s/n, Telde, Las Palmas, 35200, Spain. Email:
[email protected] Instituto Andaluz de Investigación y Formación Agraria, Pesquera, Alimentaria y de la Producción Ecológica (IFAPA), Huelva, Spain.
We present a comparative analysis of satellite derived climatologies in the Cape Verde region (CV). In order to establish phytoplankton variability, in relation to other oceanographic phenomena, a set of relatively long (from five to eight years) time series of chlorophyll, sea surface temperature, wind and geostrophic currents were ensembled for the Eastern Central Atlantic (ECA). We studied seasonal and inter annual variability of phytoplankton content in relation to the rest of the variables, with a special focus in Cape Verdian waters. We compared the situation within the archipelago with those of the surrounding marine environments, such as: North West African Upwelling (NWAU), North Atlantic Subtropical Gyre (NASG), North Equatorial Counter Current (NECC) and Guinea Dome (GD). At the seasonal scale CV region behaves partly as the surrounding areas, nevertheless, some autochthonous features were also found. In fact the good anticorrelation between chlorophyll and temperature (lower temperatures associated to higher chlorophyll contents) which is found all over the ECA, was found only in the western part of the archipelago, while towards the eastern part a shift to positive correlations was encountered, this mean that high levels of chlorophyll are accompanied by high temperatures. This is a unique feature given that none of the surrounding environments showed a similar behaviour. This enrichment was found to be preceded by a drastic drop in wind intensity (SW Monsoon) during summer months. This behaviour was shared by the NECC and to some extent by the GD areas. Satellite animations suggest that this chlorophyll maximum is transported from the east and south east. In order to better characterize this feature a study of the transport patterns to CV archipelago was performed using numerical models which prescribed advection and diffusion in the area forced by scatterometer and altimeter data. Inter annual variations of phytoplankton in CV area are sharply marked by an absolute maximum in 1999 all around the archipelago. In the northern and western part the year 2000 presented chlorophyll concentrations above normal. This behaviour, which can be related to an absolute minimum in sea surface temperatures during 1999 and a relative minimum in 2000 was also observed in the Canary Islands area and to a lesser extent in NASG waters in general. Within the CV this variability is more pronounced in the northern and western parts, while to the south and east it is not so clear, although 1999 was the absolute maximum by large. In equatorial areas near CV this behaviour was not encountered at all. In fact in GD waters the absolute maximum occured during 2002 in accord with relatively high winds and relatively low temperatures. In NECC waters, interannual variations were quite small in both of the studied parameters. This anomalous event is likely associated with long scale variation of the circulation (NAO, ENSO) and represents an increase of around 200% chlorophyll concentration. 87
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL3 P14
Oxygen and chlorophyll measurements from a Volunteer Observing Ship (VOS) in the eastern south Atlantic Ocean P. Rizzo-Aparicio, I. Rodríguez-Ucha, J. Santana-Casiano and M. González-Dávila Universidad de Las Palmas de Gran Canaria, Campus de Tafira, Edificio de Ciencias Básicas, Las Palmas, 35017, Spain. Email:
[email protected]
In the frame of CARBOOCEAN Project the QUIMA-VOS line is monthly monitoring the eastern South Atlantic Ocean, measuring surface temperature, salinity, oxygen and Chlorophyll a. In this work the annual pattern of oxygen, chlorophyll, temperature and salinity are shown for the 5º-10ºS latitudinal band inside the Eastern Tropical Atlantic Province (ETRA), between 15º-20ºS and 25º-30ºS zones in the Benguela Current Coastal Province (BENG). An inverse correlation between the temperature and the oxygen was observed related to its effect on the solubility of the gas. The role and influences of the different oceanographic structures on the oxygen and chlorophyll a measurements as described considering the Angola Dome, the Angola-Benguela Front, the Benguela Current system (oceanic and coastal) and the Benguela upwelling system.
Poster: PL3 P15
Characterisation of the southern Caribbean upwelling system D. Rueda Roa1,2, T. Ezer3 and F. Muller-Karger4 Institute for Marine Remote Sensing, College of Marine Science, University of South Florida, St. Petersburg, FL 33701, USA. Email:
[email protected] 2 Escuela de Ciencias, Universidad de Oriente, Cumaná, Edo. Sucre, Venezuela. 3 Center for Coastal Physical Oceanography, Dept. of Ocean, Earth & Atmospheric Sci., Old Dominion University, USA. 4 School for Marine Science and Technology, University of Massachusetts, USA. 1
The southern Caribbean is an area of active coastal upwelling, where at least two annual upwelling events are observed. A primary upwelling with 2-3 pulses occurring during December-May, and a shorter (few weeks), secondary upwelling event occurs between June and August. The secondary upwelling was identified through observations collected by the CARIACO Time Series Project, based in the southeastern Caribbean Sea, which started in 1995. Here we present evidence that this secondary upwelling is in fact a regular feature of the entire southern Caribbean upwelling system. It is well accepted that the main winterspring upwelling is caused by offshore Ekman transport induced by the strong Trade Winds occurring during winter-spring. However, the secondary upwelling occurs when the Trade Winds in the southern Caribbean are weakening and its genesis is not yet well understood; although, we have found evidence that this event could be driven by changes in the regional, basin-wide curl in the wind. The upwelling cycle in the southern Caribbean Sea was studied using several datasets, including a time series of twelve years of weekly mean satellite-derived Sea Surface Temperature (SST) images and thirty years of sea level records from Cumaná (Venezuela). SST data were extracted from a total of 177 stations evenly distributed along the southern Caribbean coast from Colombia to Trinidad; creating a time series that allows studying the spatial and temporal distribution of the upwelling events. The secondary upwelling presents a single pulse between July-August, although it tends to appears earlier in the eastern than in the western southern Caribbean. On average, it is 1-2°C warmer than the primary upwelling event and usually takes place in the same areas as well. Short and localized decreases in the SST are also seen around October in some years. An exception to the southern Caribbean upwelling cycle was found off the Colombian southwestern coast, where the secondary upwelling SST signal is weak and the primary upwelling period is reduced to February and March, a characteristic that seems to be related to the effects of higher riverine outflow and the warm Panama-Colombia Gyre in the area. Monthly-means of coastal sea level were well-correlated with SST (R=0.85, n=76), suggesting that tide gauge records can serve as a proxy for the upwelling cycle in the area. Three decades of monthly sea level anomalies from Cumaná (since 1948), together with 12 years of Caribbean SST records, reveal that this is a regular feature of the southern Caribbean upwelling system. Although this secondary upwelling is shortlived and less intense than the primary event, it leads to a longer annual period of productivity in the region (7 months or longer). We believe this has important fisheries implications, since it is believed that the weak 2004-2005 upwelling season was the cause of the near-collapse of Venezuela’s sardine fishery industry. 88
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL3 P16
Temperature and productivity calibration along the southern Portuguese margin, using modern planktonic foraminifera trace element and stable isotope proxies E. Salgueiro1,2,3, P. Martin1 and F. Abrantes2,3 Geophysical Sciences Department, The University of Chicago, 5734 S. Ellis Avenue, Chicago, IL, 60637, USA. Email: esalgueiro@ uchicago.edu 2 Dept. Geologia Marinha, Instituto Nacional de Engenharia, Tecnologia e Inovação I.P., Alfragide, Portugal. 3 CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Portugal. 1
The latitudinal and longitudinal temperature and productivity changes along the southern Portuguese margin (35.5 - 38.5ºN, 7 - 11ºW) were assessed by planktonic foraminiferal trace elements (Mg/Ca, Ba/Ca, Cd/Ca) and stable isotopes from core-top sediment samples. These data were compared with present-day data collected in the region to calibrate sea surface temperature (SST) and nutrient proxy for this seasonal upwelling region. Three species with different depth habitats, each linked to specific hydrographic conditions, were used for this study area. Globigerina bulloides an upper water column species, reflects the modern summer coastal upwelling with cold waters and high primary productivity close to the coast along the southwestern margin. Globigerinoides ruber (white) a surface dwelling species, and Globorotalia inflata a deep dwelling species, are both associated with the Portugal Coastal Countercurrent, a winter-time warm current. They also show higher abundance on the southern margin where upwelling only occurs occasionally, and offshore of the southwestern coast, outside of the direct influence of coastal upwelling (well stratified surface waters). Preliminary results show that the Mg/Ca and δ18O values, and the derived SSTs, of all three planktonic foraminifera species mirror the seasonal temperature changes in the water column: (1) G. ruber (white) reflects the surface conditions (~10 m water depth) of the warm waters of the Portugal coastal countercurrent (PCCC) during the winter; (2) G. inflata indicates the winter mixed layer and is also present in the PCCC; (3) G. bulloides, the summer upwelling species (lives in the upper 100 m water depth), appears to migrate during the upwelling to waters close to the surface (~10 m). This species reflects colder summer surface temperature conditions along the southwest coast than along the south coast. The Ba/Ca, Cd/Ca and δ13C values for the three planktonic foraminifera species imply a complex relationship among the nutrient tracers (Ba, Cd and δ13C) and the nutrient content of the southern Portuguese margin water masses. Taken at face value, each of the considered nutrient proxies and each of the three foraminifera species seems to record different nutrient information. For example, G. bulloides data suggest higher nutrients related with the upwelling waters whereas G. inflata imply higher nutrients at the base of the thermocline. A consistent view of the entire suite of foramiferal data requires a re-assessment of the effect of nutrient cycling on the proxies. The insights gained from this study will be applied to estimate past climate conditions not only in this particular region but also in other upwelling areas.
Poster: PL3 P17
Combination of different techniques and methods for the study of water quality and detection of harmful algal events in Ría of Vigo (NW Spain) E. Spyrakos, D. Pérez, Á. Mosquera Giménez, A. Acuña, C. Guisande, Á. González-Fernández and J. Torres Palenzuela Universidad de Vigo, As Lagoas Marcosende, 36310 Vigo, Spain. Email:
[email protected]
Remote sensing and immunological techniques as well as microscopical and chemical methods, High Performance Liquid Chromatography and flow cytometry (conventional and continuous imaging) were applied for the analysis of several selected parameters of the aquatic environment. The aims of the study were to evaluate the water quality and detect harmful algal events in an upwelling area (Ría of Vigo, NW Spain) where harmful algal events are a periodic phenomenon. For the purpose of this study two samplings were carried out in July and in October 2007 at Ría of Vigo. Water samples from the surface to three meters and net samples of zooplankton and mussel larvae were collected. Furthermore, optical (downwelling irradiance and upwelling radiance from the water surface) and physicochemical data were measured in 89
Eastern Boundary Upwelling Ecosystems Symposium situ. Indirect immunofluorescence using specific monoclonal antibodies as a tool for the detection of the dinoflagellate Alexandrium minutum and mussel larvae Mytilus galloprovincialis in the Ría of Vigo was also performed. In this study the data computed from Medium Resolution Imaging Spectrometer (MERIS) and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, regarding concentrations of chlorophyll a, total suspended material and coloured dissolved organic material are discussed and compared with the in situ measurements. Mean chlorophyll a concentration ranged from 1.12 to 3.43 μg/L in July and from 0.76 to 6.25 μg/L in October while mean total suspended matter concentration ranged from 1.61 to 2.60 mg/L in July and from 1.38 to 3.01 mg/L in October. Toxic phytoplankton species belonging to the genus Pseudonitzschia and Dinophysis were recorded in the study area in July but in relative low abundances. The first results show that remote sensing, immunological techniques and automatized methods (continuous imaging flow cytometry and flow cytometry) can be useful tools for the study of the water quality and detection of harmful algal events in the Ría of Vigo.
Poster: PL3 P18
Eastern boundary upwelling systems size variability, 10 years of satellite data. G. Yuras and S.E. Hormazabal Department of Geophysics, University of Concepción, Casilla1 60-C, Concepción, Chile. Email:
[email protected]
The high productivity in the eastern boundary current systems is due to coastal upwelling, mainly driven by the equatorward alongshore wind stress. The offshore size of an EBC upwelling system (EBCUS) has a direct impact on factors such as the export of nutrient rich upwelled waters into the low nutrients oceanic ones, and may also determine the distribution area of the early stages of pelagic fishes of economic importance. Here we follow the Nixon and Thomas [2001] approach assigning the 1 mg m-3 chlorophyll concentration as the limit of the upwelling ecosystem, and using a ten year series of daily SeaWiFS GAC data, we detected the 1 mg m-3 chlorophyll isoline. The area between this isoline and the coast for the California, Chile-Peru, Canarias and Benguela upwelling systems was also calculated. The annual and inter annual variability of the upwelling systems size is discussed and related to local and remote forces. Funding: PBCT CONICYT ACT-19, FONDECYT 1070504.
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PL4
Integrated end-to-end food web studies of upwelling ecosystems
2 June, 17:30 (PL4 KNS)
Functional response in a size-based world: a simulation experience in the Benguela ecosystem Y-J. Shin, M. Travers and P. Cury Centre de Recherche Halieutique Méditerranéenne et Tropicale, IRD, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected]
Conceptual models of predation usually connect predator species and prey species. However, the quantification of trophic interactions on a species basis is difficult in pelagic ecosystems because fish diets are highly variable in space and time and are diversified, fish are life-history omnivores, and cannibalism is frequent. Based on these observations, many studies support the hypothesis that predation is opportunistic and conditioned by size constraints mainly. The objective of this paper is to explore the consequences of such an hypothesis in the quantification of trophic interactions and in the type of functional responses that can be expected in upwelling ecosystems. We use an end-to-end model coupling a model of high trophic level Osmose with a model of low trophic level Roms-NPZD to simulate the predator-prey interactions in the Benguela ecosystem, with a focus on fish interactions. The model Osmose is a multispecies and individualbased model of fish communities with basic constraints on predation: spatio-temporal co-occurrence and size adequation between predators and their prey. From these individual rules, we observe the emergence of functional responses at the species level. Different types of functional responses are obtained in the simulations depending on the degree of omnivory, on the production seasonality, and on the species dominance. This study opens perspectives for better quantifying and generalizing predator-prey interactions in situ and in other modelling approaches. Acknowledgements: This is a contribution to EUR-OCEANS Network of Excellence funded by the European Commission (contract FP6-511106), and to the French ANR "Chaloupe" project.
2 June, 18:00 (PL4 OP1)
Comparison of two modelling approaches for addressing changes in the food web structure under scenarios of overfishing in the southern Benguela M. Travers1, K. Watermeyer2, Y-J. Shin1 and L. Shannon2 Centre de Recherche Halieutique Méditerranéenne et Tropicale, IRD, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected] 2 Marine and Coastal Management, South Africa. 1
One of the potential strengths of ecosystem models is that they provide a platform from which to explore the possible responses of marine food webs to fishing pressure and various potential management decisions. In this study we investigate the particular effects of overfishing on the structure and function of the southern Benguela food web, using two models with very different underlying assumptions. Osmose is a spatial individual-based model, simulating opportunistic trophic interactions based on size suitability between prey and predator and spatio-temporal co-occurrence. Coupled with a biogeochemical model of plankton, it simulates the dynamics of organisms ranging from plankton to large fish. Ecopath with Ecosim is a dynamic model which represents a range of marine organisms across several trophic levels, aggregated in boxes. These boxes are trophically linked accordingly to diet data, thus leading to a static food web linkage pattern which can be altered over time using the dynamic Ecosim routine. Starting from the same reference state of the southern Benguela upwelling ecosystem during the 1990s, we compare the response of the food web to scenarios of overfishing using these two modelling approaches. A scenario of increased fishing mortality is applied to two distinct functional groups: i) to two species of Cape hake, representing important targeted top-predators, and ii) to the forage species anchovy, sardine and redeye. In these simulations, fishing mortality on the selected functional groups is increased for 10 years, followed by 10 years of the original fishing mortality. We compare the food web states before the increase of fishing mortality, after 10 91
Eastern Boundary Upwelling Ecosystems Symposium years of overfishing and after the 10 years of possible recovery. In order to compare the simulated food web structures with the reference state, and between modelling approaches, we use a set of relative trophic and network indicators. Specifically, we consider the following trophic indicators: of the change in the mean trophic level of the community and in catches, the trophic pyramid (biomass per discrete trophic level), the relative ranking of species trophic levels, predatory/forage fish ratio, and as network indicator we consider the change in the mean path length.
2 June, 18:15 (PL4 OP2)
Effects of climate variability on ecosystem structure and function in the Gulf of the Farallones, California J. Jahncke1, M. Elliott1, B. Saenz2, R. Bradley1, J. Roth1 and W. Sydeman3 Marine Ecology Division, PRBO Conservation Science, 3820 Cypress Dr., #11, Petaluma, California, 94954, USA. Email:
[email protected] 2 Stanford University, USA. 3 Farallon Institute, USA. 1
We examine temporal and spatial associations between seabirds, prey and oceanographic processes in the Gulf of the Farallones, Central California. We found evidence that oceanographic conditions influenced the availability of prey for upper trophic level predators, and affected their timing of breeding, reproductive success, as well as their overall abundance and distribution. Climate variability affects birds and other predators by means of changes in their food webs. This study provides examples of shifts in biology due to marine climate on several species and explores the trophic and ecological interactions behind these changes. Climate change may have unexpected consequences because different species show unique responses to changes in their environment.
2 June, 18:30 (PL4 OP3)
Mechanisms affecting resilience in an upwelling food web model: the case of the southern Humboldt S. Neira1,2, C. Mullon2, C. Moloney1 and P. Cury2 1 2
Marine Biology Research Centre, University of Cape Town, Rondebosh, 7702, Cape Town, South Africa. Email:
[email protected] Centre de Recherche Halieutique Méditerranéenne et Tropicale, IRD/IFREMER/Université Montpellier, France.
Although bottom-up forcing and overfishing are known to induce shifts on ecosystem states, system changes and their reversibility under each factor are still poorly understood. In this paper, dynamic food web simulations are conducted to evaluate ecosystem shifts and recovery under bottom-up, fishing (top-down) and vulnerability/availability of plankton prey. Simulations are conducted using a calibrated food web model of the upwelling system off central Chile (33º-39ºS) and the Ecopath with Ecosim software version 5.1. The effects of fishing scenarios are explored by changing fishing mortality according to trophic level. The effects of bottom-up forcing scenarios are explored by changing phytoplankton biomass as function of sea temperature at El Niño Southern Oscillation (ENSO) and decadal scales. The effects of plankton prey vulnerability/ availability are explored as function of sea temperature at El Niño Southern Oscillation (ENSO) and decadal scales. Simulations are carried out for 150 years and impacts, system recovery and ecosystem shifts induced by each forcing are evaluated using trophodynamic indicators and limit reference points as proxies of food web state and ecological thresholds, respectively. Equally distributed fishing along trophic levels is the least harmful fishing scenario, resulting in low biomass limit reference points exceeded and high system recovery. Concentrating fishing at higher and lower trophic levels exceeds reference points and induces ecosystem changes with low-to-medium recovery potential. No limit reference points are exceeded (or regime shift induced) under ENSO scale bottom-up forcing. Decadal scale bottom-up forcing has different effects on the system depending on the sequence in which the high and low phytoplankton biomass period is simulated. A shift from low phytoplankton biomass towards high phytoplankton biomass does not result in biomass limit reference points being exceeded, whereas the opposite sequence results in a large number of limit reference points being exceeded with medium recovery. Vulnerability settings induce slow/fast changes depending on whether bottom-up or top-down control is forced. The interplay between fishing and decadal scale bottomup forcing indicates that bottom-up forcing can dampen the effects of fishing, whereas fishing increases the number of limits reference points exceeded and decreases the recovery observed under decadal scale bottom-up forcing. Results suggest that fishing is more likely to exceed ecological thresholds and induce regime shifts of low recovery than decadal scale bottom-up forcing or vulnerability/availability scenarios. 92
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2 June, 18:45 (PL4 OP4)
Influence of ocean winds on the pelagic ecosystem in upwelling regions R. Rykaczewski and D. Checkley Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Dr., MC 0208, La Jolla, California, 92093-0208, USA. Email:
[email protected]
Upwelling of nutrient-rich, subsurface water sustains high productivity in the ocean's eastern boundary currents. Environmental variability is considered the major cause of decadal fluctuations characteristic of fish populations in these regions, but the mechanisms relating atmospheric physics to fish production remain unexplained. Two atmospheric conditions induce different types of upwelling in these ecosystems: coastal, alongshore wind stress, resulting in rapid upwelling (higher vertical velocity, w); and wind-stress curl, resulting in slower upwelling (low w). We present a mechanism relating production of Pacific sardine (Sardinops sagax) in the California Current Ecosystem (CCE) with wind-stress curl over the past six decades. Records of density, nutricline depth, and chlorophyll concentration in the upper ocean are supportive of this mechanism. The size structure of plankton assemblages is related to the rate of wind-forced upwelling. We propose that and sardine feed efficiently on smaller plankters generated by slow, curl-driven upwelling. Prior to the 1970s, coastal, alongshore wind stress played a more important role than curl in ecosystem variability. Since the 1970s, the relative strength of curl-driven upwelling has increased, while the level of coastal upwelling has remained constant.
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PL4 Posters Poster: P4 P1
The role of the relationship between primary production and monterrey sardine exploited stock on the dynamics of the central Gulf of California ecosystem F. Arreguin-Sanchez and S. Martinez-Aguilar Centro Interdisciplinario de Ciencias Marinas del IPN, Instituto Politécnico Nacional s/n, Col. Palo de Santa Rita, La Paz, Baja California Sur, 23090, Mexico. Email:
[email protected]
The relationship of primary production and sardine stock size is well known and characteristic of highly productive ecosystems. This relationship has three key attributes; 1) is variable following primary production pulses, 2) has a considerable impact on the ecosystem following a button-up control in the food web, and 3) sardine sustain an important fishery. We investigate the dynamics of these relationships in order to understand how variation in primary production is propagated through the food web as well as the role of sardine as foraging species and as fish resource. We used a dynamic trophic model for the ecosystem of the central Gulf of California based on Ecosim. Time series of primary production and sardine stock size are used to calibrate the model. To test the role of the sardine in the food web we compute changes for several ecosystem indicators under different levels of primary production available in the ecosystem. For the same scenarios we also analyze changes in the sardine stock size and catchability variation. Primary production fluctuations represent changes the energy available to sustain ecosystem structure and function; then in our analysis changes in the ecosystem supply-demand energy balance (as represented by primary production) is related to changes in the ecosystem structure and function, as well as on the sardine stock dynamics and its fishery. Our results indicate a strong picture representing bottom-up control but more importantly, that sardine fishing could potentially have a strong impact on the ecosystem if low sardine stock abundance coincides with low supply of energy (low primary production) and high harvesting rates.
Poster: P4 P2
An online tool for end-to-end ecosystem model developers: EUR-OCEANS’ Model Shopping Tool (MoST) I. Grigorov1 and O. Aumont2 EUR-OCEANS, CNRS, Institut Universitaire Europeen de la Mer, Place Copernic, Technopole, Plouzane, 29280, France. Email:
[email protected] 2 IRD, Brest, France. 1
Pelagic Ecosystem Modelling incorporates a highly diverse range of approaches and philosophies resulting in a variety of question- and study-specific modelling tools. With the immerging need to model ecosystems end-to-end, and assess physical and anthropogenic forcing on them in the near future, the variety of existing global 3D biogeochemical models need to be coupled to food web and top predator models. As a first step to promote pelagic ecosystem model interfacing with the eventual goal of ecosystem endto-end modelling, a prototype online tool for developers has been constructed under the EUR-OCEANS Network of Excellence. The Model Shopping Tool (MoST – www.eur-oceans.eu/models) offers four main products: 1) a searchable databank of descriptions of philosophy and approach of the major global ocean biogeochemistry models, zooplankton and food web models, most of which have been supplied or quality controlled by the model developers themselves; 2) a searchable databank of the equations of the state variables and main processes represented in those models, together with parameter definitions, values and sources where available; model developers and process scientists alike can quickly search for and compare across models the formulation of a particular biological process in the major pelagic ecosystem models, and assess for themselves the advantages and shortfalls of the different modelling tools in use; 94
Eastern Boundary Upwelling Ecosystems Symposium 3) an integrated database of over 20 000 datapoints on key species vital rates that collates known datasets already used or that can be used to validate and parameterize the vital rates of species of key importance to end-to-end ecosystem models; 4) in development, an online prototype of a 1D, global biogeochemical model simulator that allows users to design and run customized simulations for any global location and compare model output with observations (resolution 2o x 2o degrees, based on PISCES 1D, with NEMURO and ERSEM planned to be included).
Poster: PL4 P3
Study of the diet of the Octopus vulgaris in the Moroccan south Atlantic I. Farah Hounaida1,2, N.Charouki1 and D. Belghyti2 1 2
Institut National de Recherche Halieutique, 2 Rue Tiznit Casablanca. Morocco. Email:
[email protected] Université Ibn Tofail Faculté des Sciences. Laboratoire d’Océanologie Hydrobiologie et de Parasitologie, Morocco.
This work aims to study the diet of the Octopus vulgaris in southern Atlantic Moroccan coast, in order to contribute to a better knowledge of its ecology and its dynamism. The study was carried out from the commercial landings of the coastal trawlers in Agadir during the cycle 2001-2003. An additional sample of 119 individuals was also obtained in the area between Boujdor and Lagouira during the surveys conducted during the two biological rests (April- March and September-October) in 2001 and 2002. The individuals of Octopus vulgaris were sampled monthly, and their sex and state of maturity were identified. The stomachs were then taken and measured; the data of the stomachs contents was analysed by the index of relative importance (IRI) which integrates occurrence, numerical and weight percentages of the identified preys. The specific analysis of the stomachs contents reveals a predominance of shellfish and mollusc. The study of the consumed preys indicates a cannibalism phenomenon in the adult during the summer season. The diet of the octopus varies according to the seasonality and the sexual maturation.
Poster: PL4 P4
Long-term changes in fishery landings from the Canary–Saharan region J. Otero1, G. DingsØr2,3, G. González-Nuevo4, N.C. Stenseth3,5 and X.A. Álvarez-Salgado1 Instituto de Investigaciones Marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain. Email:
[email protected] Institute of Marine Research, Bergen, Norway. 3 Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, Norway. 4 IEO, Centro Oceanográfico de Gijón, Spain. 5 Institute of Marine Research, FlØdevigen Marine Research Station, N–4817 His, Norway. 1 2
The northwest coast of Africa has been one of the main fishing grounds worldwide for years. As an eastern boundary current system, fisheries have been based on pelagic fish representing roughly 70% of the total catches on average. Specifically, the Saharan Bank has been fished since the fifteenth century producing very profitable finfish and cephalopod yields. These high yields lead to a massive presence of different fleets in the area during the 1960s, 70s and 80s taking advantage of the introduction of new fishing (e.g. bottom trawling) and preservation (i.e. freezing) methods. By that time, sudden outbursts of different populations were documented, as well as changes in the dominant species in the landings, such as the apparent replacement of finfish–targeted fisheries to cephalopod–targeted fisheries in the early 1970s, though the reasons behind these shifts remain unclear. A combination of factors has been suggested, including economic incentives, oceanographic anomalies, species competition, and overexploitation, however, these hypotheses have never been quantitatively confirmed. Here, we review and analyse the reported landings of several finfish and cephalopod species from the Canary Islands ports for almost 50 years. Using different formulations we suggest that major changes were forced by a dynamic interplay between exploitation, biology and oceanography. The increase of fishing effort exerted a direct effect on the dramatic rise of the landings; in addition, there has been detected first-order processes (i.e. density dependent effects probably caused by inter- and intra-specific interactions), and lagged oceanographic effects, leading to an increase of the landings during upwelling favourable years. However, these results do not exclude other related processes such as economic incentives and derived effects of discards. 95
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Poster: PL4 P5
Sufflogobius bibarbatus - a success species in the Benguela upwelling system due to evolved tolerance of hypoxia and H2S A. Utne Palm1, A. Gro Vea Salvanes1 and B. Currie2 1 2
University of Bergen, Department of Biology, P.O. Box 7800, 5020 Bergen. Email:
[email protected] National Marine Information and Research Centre (NatMIRK), Namibia.
The Benguela upwelling ecosystem (on the southwest cost of Africa) is one of the most productive areas of the world. Inner shelf has high sedimentation rate and large areas covered with hydrogen sulphide sediments, where anoxic or hypoxic conditions are found in the water column above. The endemic goby, Sufflogobius bibarbatus has shown great success in this ecosystem. S. bibarbatus, is described as a pelagic goby. Our preliminary conclusion is that this goby is mostly in pelagic waters to restore their oxygen depth and to digest ingested food. They migrate upwards to more oxygenated and warmer water just after sunset and return to the deeper, colder and low oxygen water just before sunrise to avoid predation risk. Experimental studies showed that this goby has a remarkably high tolerance to low ambient oxygen. Their response to decreasing oxygen levels first by slight increase in the gill ventilation frequency and thereafter followed by a sudden drop in gill beat frequency. They tolerate 4-5 hours in levels of < 0.01 ml DO/l without showing signs of equilibrium loss, and they recover rapidly to normal breathing and behaviour after 5 to 9 hours of oxygen stress. When “attacked” (poked by a stick) after been exposed to < 0.01 ml DO/l for 5 hours, they responded immediately with an escape response, showing that their brain is turned on also after longterm exposure to an anaerobic environment. Interestingly the gobies opercula beat rate did not increase during recovery, but remained at the same level as found under the deoxygenating poses. This means that S. bibarbatus has the ability to get rid of its lactate from anaerobic respiration, as there is no sign of oxygen depth after the 4.5 hours of anaerobic respiration. Adult and juvenile gobies tolerated 5 hours in presence of H2S in anoxic (< 0.01 ml DO/l) water without showing signs of equilibrium loss. We believe that this species has evolved a remarkable tolerance to low oxygen - and high hydrogen sulphide levels, and that this is the explanation for the species great success in the Benguela ecosystem.
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PL5
Resource assessment, management and socio-economic implications of Ecosystem based management of EBUS
6 June, 10:15 (PL5 KNS)
Vessel Monitoring Systems: a review of what make them an innovative platform for ecosystem assessment S. Bertrand1,2 1 2
IRD, CRHMT, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected] Instituto del Mar del Peru, esquina Gamarra y General Valle s/n, Chucuito, Callao, Peru.
In marine ecosystems where, by essence, observation is difficult, top predators are increasingly considered as potential ecosystem indicators. Their abundance, diet and spatial behaviour would reflect ecosystem productivity and spatial structuring (e.g. session 11 of this symposium). For monitoring top predators spatial behaviour, a growing number of scientific programs are fitting birds, mammals and large fishes with telemetry loggers. Yet, in exploited marine ecosystems, fishers usually represent an important, if not the most, top predator in terms of removals. Besides, everyday a growing number of fisheries are fitted with satellite vessel monitoring systems (VMS), primarily for law enforcement purposes. We assert here that these VMS are a great opportunity for fisheries scientists and managers because they produce continuously accurate and exhaustive (all the fleet) data on fisher's spatial behaviour, at no cost for assessment and management organisations. In this review, we present first an overview of the existing VMS in the world and how the information they generate is currently used by the fishery management agencies. Then, we present the wide variety of information that can be extracted from the raw positioning data through different data processing methods: fishing effort estimates (e.g. mapping, simple statistics – path length, sinuosity, fractal dimension), fishing operations count and localization (e.g. simple speed criteria, neural network), and fisher's foraging strategies characterisation (e.g. random walk modelling). Finally, we present a series of scientific and operational perspectives opened by these spatially explicit data and their derived indexes, with special emphasis to EBUs ecosystems: (1) comparing fishers' and other top predators (birds, mammals) foraging strategies to assess their interactions; (2) quantifying the relationships between fisher's movements and fish distribution to gain insights on changes in catchability; (3) testing the impact of spatially explicit regulations on fisher's strategy; (4) supporting the implementation of areas closed to fishing (depth based or box-based); (5) supporting adaptive fishery management process by providing sentinel metrics of changes in the ecosystem.
6 June, 10:45 (PL5 OP1)
A quantitative method for coastal ecosystem performance evaluation under alternative management interventions M. Aguero1 and A. Sanchez-Arcilla2 Inter American Centre for Sustainable Ecosystem Development (ICSED), Casilla 27016, Las Condes, Santiago, Metropolitana, 6782236, Chile. Email:
[email protected] 2 International Centre for Coastal Resources Research, Spain. 1
Managing coastal and marine ecosystems presents complex problems. T hey are highly vulnerable to overexploitation and degradation resulting mainly from overinvestment and excessive extractive or use rates, triggered by ill-defined property right systems (tragedy of commons). The end result is not only less fish for future generations, eventual collapse or even extinction of the various stocks of fish and the like, but considerable loss of social and economic benefits to society due to forgone benefits from alternative uses of coastal ecosystems. Coastal areas do not only encompass fish stocks. They host a wide variety of other natural resources, some of which are renewable like fish and clean water while others are nonrenewable like iron ore and fossil fuels. Other kinds of coastal resources such as solar and aeolic energy which although nonrenewable in strict sense, provide a flow of ecosystems functions and services. On the other 97
Eastern Boundary Upwelling Ecosystems Symposium hand, some occur in the ocean like fish, crustacean, molluscs, corals and algaes and others are land-based like forests and tourist sites while mangroves, beaches and sand dunes among others are in-between. From the management or efficient resource allocation perspective, the challenge is to identify ways (policy interventions) for society to attain the highest possible net benefits (satisfaction) from the use, conservation, preservation or rehabilitation of coastal ecosystems without jeopardizing the possibilities and opportunities for future generations to enjoy similar benefits (sustainable use) while seeking an appropriate balance between conservation and use of biological diversity (CDB). Traditional management approaches and methods have generally focused on only few components of the ecosystems, failing to recognise the essential processes and interactions amongst organisms and their environment and that humans are an integral component of ecosystems. Recognising the complex web of interactions between humans, the environment and their impacts on the ecosystems performance from society’s point of view, a quantitative model to evaluate alternative management interventions was developed and applied in a recent study conducted by a collaborative effort of European and Latin-American institutions financed by the European Commission. This paper reports on the main findings of the study referred above called: ECOSUD: Estuaries and Coastal Areas. Basis and Tools for a More Sustainable Development” (Journal of Coastal Research, 2007). It presents, the scientific basis for the study and a synthesis of the tools and methods used for deriving them. In particular, a quantitative method for evaluating the Socio-economic Performance of alternative management policies in two Coastal Zones (Patos Lagoon in Brazil and the Jucar River Estuary in Spain is discussed and compared with suggestions for a more comprehensive follow-up research on this methodology. It emphasises the need for closer and stronger collaboration between scientists of the various disciplines involved in the study and management of coastal ecosystems.
6 June, 11:00 (PL5 OP2)
The effectiveness of the 200 m depth exclusion zone as a protective measure of spawning and nursery areas of commercially important fish in Namibia G. Bauleth-D’Almeida and U. Uatjavi Ministry of Fisheries and Marine Resources, NatMIRC, Strand Street, Po Box 912, Erongo Region, 9000 Swakopmund, Namibia. Email:
[email protected].
The Namibian Ministry of Fisheries and Marine Resources (MFMR) has had a management measure in place since 1991, to protect valuable spawning and nursery areas of commercially important fish. The regulation excludes commercial fishing by bottom and mid-water trawlers in waters shallower than 200 m. Due to continued pressure on MFMR from the fishing industry to review this regulation, a series of experiments were conducted to test its effectiveness. The first of these investigations was conducted in 1995 and 2002, but did not yield conclusive results. Therefore another set of experiments was conducted in July and October/November 2006 and January/February 2007. The studies were restricted to the area north of 18°35 to the border with Angola at 17°15 and involved two midwater trawlers, with one operating between 150 – 200 m water depth and the other from 200 m and deeper. The results indicated that horse mackerel formed a major proportion of the catches both inshore and offshore of the 200 m isobath, with other species, including hake, only making up 1% of the species composition. Furthermore, a clear relationship between the depth and size of horse mackerel was evident, with the size of the fish increasing with depth, in spite of the narrow distances between the depth contours in this region. The data did not support a relaxation of the 200 m depth restriction for the midwater fishery to access horse mackerel inside of this isobath. The horse mackerel cohort occurring in the proximity of this isobath, although of legal size, occurred in mixed shoals with younger cohorts unlike offshore of this isobath where mostly adult fish are found. Moreover, this cohort was predominantly made up of horse mackerel, which were just entering the adult population, with only about 50% being sexually mature. 98
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6 June, 11:15 (PL5 OP3)
A regional information system for improving fisheries governance and assessment, structure and contents J. Guitton1, A. Sidibe2, B. Masumbuko3, E. Beibou4, M. Soumah5, P. Cauquil6 and P. Chavance6 Fisheries and Aquatic Sciences Center. Agrocampus Rennes / IRD US Osiris, France. Email:
[email protected] Sub Regional Fisheries Commission, Senegal. 3 IRD US Osiris, Senegal. 4 IMROP, Mauritania 5 Database administrator, Guinea. 6 IRD US Osiris, France. 1 2
The EU funded Istam Project aims to provide some tracks in order to improve scientific advice on the state of fisheries. One of our lines of research is to develop a prototype of regional information system suited to give all the tools to improve the scientific advice and to disseminate it. Thanks to our proximity with the fisheries data and information users, we attempted to offer tools that could be useful within the different aspects of their work. They are tools to understand how the data are collected and managed, how to get them, which methods have been used for a particular assessment. These types of information are more dedicated to scientists who want to redo an assessment or gauge its quality. Tools for an easy access to the final diagnosis and to the fisheries regulations already in place are meant for the fisheries manager or for the scientist who want to have a global view of the fisheries ecosystem. The prototype can be found on the web available through a web interface and provides six types of information necessary for the fisheries assessment and management: First, we can access to the inventory and description of the monitoring systems, then •
we also provide raw or aggregated data to input into some models to produce the advice
•
we provide all the methodology used to create the advice: data input, description of the models and results
•
we disseminate the advice itself
•
we provide information on fisheries regulations, which could be the result of advice likely to influence the next, updated advice on the same stock or fisheries
The Istam prototype is an integrated framework which makes information on the fisheries easier and more documented to help develop new advice. A friendly website that integrates all pieces of our puzzle of information has been set up. On the interface there are resources for the diagnosis provider or the wider public such as the online atlas of the data, and for the specialist who needs to access raw data on a specific database. We will start with a presentation of the Istam project, followed by an overview of the work in progress and the issues it raises.
6 June, 11:30 (PL5 OP4)
Exploring policy options and tradeoffs in the northern Benguela ecosystem J. Heymans1, U. Sumaila2 and V. Christensen2 Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Dunbeg, Argyll, PA37 1QA, United Kingdom. Email:
[email protected] 2 Fisheries Centre, University of British Columbia, Canada. 1
Alternative policy options available to northern Benguela fisheries managers were explored, testing scenarios such as optimizing the discounted profit from the fisheries in the ecosystem, maximizing the jobs that can be provided by the fisheries, maximizing a measure of ecosystem status, and analysing tradeoffs of these. Additionally, different discount rates and subsidy scenarios were tested. The results show that: Discounted profit can be more than doubled if the demersal fleet, crabs, commercial line fishery and lobster fisheries increased their effort, but at a 10% cost to the ecosystem; Three times more jobs can be obtained if the demersal, longline, crab, lobster and commercial line fisheries are increased but this will be at a substantial cost to the ecosystem; Optimizing the ecosystem status is achieved by increasing the 99
Eastern Boundary Upwelling Ecosystems Symposium purse seine fleet and reducing most other fleets substantially, but that reduces the profits and jobs by about 50%. Tradeoff analysis showed that the total catch, trophic level of the catch and diversity of the ecosystem were dependent not only on the incremental importance placed on profits, jobs or the ecosystem, but also on whether the fisheries were being subsidized. The effect of subsidies were not easily categorised, as it depended on the trophic level of the fish caught by the fleets, the fleet cost structure, the prices received for the catch, on the one hand, and the emphasis placed on jobs, profit, ecosystem by the managers, on the other hand, and whether these cancel out the expected effects of subsidies.
6 June, 11:45 (PL5 OP5)
Estimation of bioeconomic losses caused by the capture of juvenile Peruvian Hake (Merluccius gayi Peruanus Guilchenot, 1848) for the commercial coastal fleet in the Peruvian sea during 1993-2006 H. Olivera, E. Barriga and C. Salazar Instituto del Mar del Peru, Esquina Gamarra y General Valle s/n Chuchito, 4297630-anexo 282, Peru. Email:
[email protected]
Landings of Peruvian hake off Northern Peru have been characterised by a high percentage of juvenile individuals since 1992. This work analyses biomass and economic loss caused by juvenile catches on coastal trawl vessels during 1993-2006. The analysis is based on the size composition of landings in Paita (05°05’S). The biomass projections were carried out by means of the Thompson and Bell model using the von Bertalanffy growth parameters and the natural mortality rate provided by Peruvian Marine Research Institute (IMARPE). The biomasses were projected until the fraction of individuals < 35 cm reached a percentage less than 20%. The economic loss was estimated by subtracting the value of the landing from the value of the projected biomass. The conversion coefficients, estimated using the relationship between the yield of hake fillet and the length of the individuals, and prices for export (FOB-Paita) were used to estimate the production and value of filet by range of size. Moreover, the industrial demersal fishery of Peruvian Hake was analysed through a bioeconomic approach including statistical data from the fishery (catch and effort between 1993-2006) and economic data (costs and revenues between 2001-2003) using a Gordon-Schaefer model using Maximum Likelihood. Results showed that when projecting real landings, biomasses increased by 27,3% and the value of the processed biomasses, like fillet, increased between 43,6 and 47,7%. In relation to landing value and biomass projected for the period 1993-2006, a difference between 142 and 168 million dollars was obtained. The biological and economic reference points determined by the Gordon-Schaefer model using Maximum Likelihood showed that the commercial coastal fleet has harvested above the effort in maximum economic yield (EMEY) during 1995-1997 and 2000-2001, while their catches exceeded the Maximum Sustainable Yield (MSY) during 1995-1997 and 2001. We discuss the impact of this fishing strategy on the population dynamics, and some management measures are suggested to increase the biological and economic yield of this species.
6 June, 12:00 (PL5 OP6)
An investigation into spawner-recruitment relationships, including environmental parameters, and the development of reference points for the Namibian sardine (Sardinops sagax) C. Kirchner and C. Bartholomae National Marine Information and Research Centre, Ministry of Fisheries and Marine Resources, P.O.Box 912, Swakopmund, Namibia. Email:
[email protected]
The Namibian sardine stock is currently at an extremely low level and is made up of only about three age classes with an average fish size of 21 cm. Despite these low stock levels, catches were allowed for all years, except 2002. With such a limited stock it is understandable that every year the fishing industry is dependent on recruitment for their Total Allowable Catches. It was found that at extremely low levels of spawner numbers the recruitment is highly depended on environmental conditions, represented here by indices for upwelling and Angola-Benguela frontal movement. There is approximately a 25% chance that environmental conditions are favourable for recruitment in any particular year. Reference points (target, precautionary, limit and crash), harvest and decision rules were developed using historic spawner100
Eastern Boundary Upwelling Ecosystems Symposium recruitment information and the more recent environment-recruitment relationships. Considering the results it is expected that the sardine stock will fall below the Crash Reference Point in the near future. Should the management plan be accepted by then, a four-year moratorium would have to be implemented to save the stock from extinction although such a measure would be detrimental to the fishing industry, which is already under a lot of strain.
6 June, 12:15 (PL5 OP7)
Viable control model for management of fisheries: the case of Peruvian hake Merluccius gayi Peruanus R. Oliveros-Ramos1 and J. Tam2 PUCP, Departamento de Ciencias, Pontificia Universidad Católica del Peru. Av. Universitaria 1801, San Miguel, Lima 32, Peru. Email:
[email protected] 2 Instituto del Mar del Peru, Modelling Research Center, Peru. 1
The problem of fishery sustainable management is still an open problem, and viability theory offers an alternative to define management policies that guarantee sustainability. Hake Merluccius is a common and dominant demersal genus of many eastern boundary upwelling systems (EBUS). In Peru, hake (Merluccius gayi Peruanus) was overexploited in the 2000s, and despite reduction of catches, it has not recovered yet. In this work, we compute the viability kernel, viable fishing mortality and viable yields for Peruvian hake using the logistic model with harvest for biomass population growth. We compared historical time series with simulations obtained from viability theory in the biomass-yield phase space, interpreting different scenarios. The analysis suggests that in recent years, Peruvian hake was mostly outside the viability kernel.
6 June, 12:30 (PL5 OP8)
Mega scale patterns of ‘loco’ catches along the Chilean coast: from coastal oceanography to improved scientific advice for management B. Yannicelli1,2, J. Letelier2, J. González2, L. Orensanz3 and A. Parma3 Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Facultad de Ciencias del Mar, Universidad Católica del Norte, Chile. Email:
[email protected] 2 División Pesquerías, Instituto de Fomento Pesquero, Chile. 3 Centro Nacional Patagónico (CENPAT), Argentina. 1
There is general agreement among fishery scientists that the design of management strategies for benthic fisheries requires integration of information at several spatial scales. However, no clear framework has been established for the identification of the relevant scales for modelling population dynamics. We address this problem with the Chilean carnivorous gastropod ‘loco’ (Concholepas concholepas). Following a total closure of the loco fishery in 1990-1992, two different management regimes were sequentially implemented: [i] the ‘benthic extraction regime’ (BER, 1993-1997), through which the total allowable catch was divided into individual divers, and [ii] allocation of territorial use rights, as ‘management and exploitation areas for benthic resources’ (MEABR, starting in 1998). We compared the mega-scale spatial pattern of loco catches from the BER and AMERB periods along the Chilean coast between 20º to 45ºS, and analysed their relationship with coastal topography, mean coastal chlorophyll a (Chl a) concentration, and landings of loco’s main prey items. The port-sampling program conducted by Chile’s Fisheries Development Institute (IFOP) provided BER landings associated with geo-referenced fishing locations. MEABR catches were extracted from annual reports provided by the Chilean Under-secretariat of Fisheries. Topography was incorporated as an index of coastal convolution: the linear length of coast per 0.063 degree of latitude. Chl a concentration integrated in the 20 coastal km from weekly 4×4 km Modis-Aqua images were averaged between 2002-2007. Catches by fishing location of the barnacle Astromegabalanus psittacus and the tunicate Pyura chilensis (main prey items of loco) were available from IFOP’s port sampling program. We identified several zones that contributed the highest mean catches under the BER. It is in those productive zones that the MEABRs with highest current landings are located implying that the effectiveness of caring under the new regime was conditioned to natural levels of loco productivity. Two exceptions are noticed in the southernmost and northernmost locations where regulatory constraints might explain this discrepancy. 101
Eastern Boundary Upwelling Ecosystems Symposium Areas yielding high catches coincide with sectors where the coast is more convoluted, with coast-scrapes rich in geographical features (headlands, bays, islands). The latter are associated with high coastal primary productivity (PP). The interaction of upwelling favourable winds and coastal currents with headlands/ islands favor the development of upwelling and/or recirculation that in turn may enhance larval retention and PP. These areas also have high abundances of the two main loco food items, both filter feeders. Overall, large-scale spatial consistency among these phenomena suggests that the concentration of higher resource productivity within the areas recognised sets the appropriate scale for integration and modelling of population processes. Our results have implications for future analysis and management: [i] historical landings could be used to evaluate the productivity potential of the MEABRs, to establish harvest reference points, and to determine the effectiveness of local management plans; [ii] sectors of the coast are definable on the basis of multiple-process consistency, including oceanographic forcing and population responses. This information will be indispensable to define natural mesoscale strata for strategic analysis and planning.
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PL5 Posters Poster: PL5 P1
Dispersal mechanisms and abundance of Octopus vulgaris in the Cape Blanc upwelling system E. Balguerías1, A. Solari2 and J. Castro3 IEO, Área de Pesca, Avenida de Brasil, 31, Madrid, 28080, Spain. Email:
[email protected] IEO, Universidad de Las Palmas de Gran Canaria, Centro Ocean. de Canarias, Spain. 3 Universidad de Las Palmas de Gran Canaria, Gran Canaria, Spain. 1 2
The common octopus (Octopus vulgaris Cuvier, 1797) is a widely distributed species with a life span of about one year. In the upwelling system of Cape Blanc octopus forms very dense aggregations which are the target of specialised fishing fleets constituting the most important fishery in the world for the species. Two different stocks have been identified along the Northwest African coast between 19ºN and 26ºN (Saharan Bank) where the core of the Cape Blanc up-welling system occurs. These stocks are respectively distributed north of Dakhla (24ºN) and around Cape Blanc (21ºN). Both the restricted distribution of the stocks and their abundance seem to be very much related to oceanographic processes prevailing in the area during the paralarvae phase of the species. Retention mechanisms by eddies arising from upwelled waters combined with prevailing environmental conditions at the hatching season of octopus are considered external forces governing both the genetic isolation and the dynamics of the stock. Using data from the Spanish octopus fishery in the Saharan Bank together with environmental information from different sources, this paper specifically address the dynamics of the Dakhla stock. A highly non-linear, multiple steady state modelling approach is applied using catch-effort, Sea Surface Temperature and Altimeter data.
Poster: PL5 P2
Deep-demersal fish assemblages in the Canary Current ecosystem L. Fernández1, C. Hernández2, A. Faraj3, M. Ould Bouzouma4 and survey teams. Instituto Español de Oceanografía, Centro Oceanográfico Malaga, Puerto pesquero s/n 29640 Fuengirola (Malaga), Spain. Email:
[email protected] 2 IEO, Centro Oceanografico de Canarias, Spain. 3 Institut National des Ressources Halieutiques, Morocco. 4 Institut Mauritanien des Recherches Oceanographiques et des Pêches, Mauritania. 1
The knowledge of composition and distribution of deep-communities of fishes in the Canary Current ecosystem and their relation with different substrata and oceanographic characteristics is very scarce. Quantitative data obtained during two surveys on board O/V “Vizconde de Eza” on November-December 2006 and 2007 are analysed. These trawling surveys were conducted by Moroccan, Mauritanian and Spanish Research Institutes in order to prospect and evaluate demersal resources between 400 and 2000 m. A total of 179 stations between 16º-26ºN were realised. The multivariate analysis shows that faunistic communities are structured by depth, but faunal discontinuities are less apparent in this area than in the non-upwelling temperate zones. In spite of the composition of these depth-dependent assemblages, that could be attributable to the restricted bathymetric ranges of several species, perhaps indicates a zonation, but the clustering of samples showed certain degree of similarity. The latitude is not an important influential factor in the area. We observed changes and replacement of certain species, as of the family Sebastidae in the North by Merluccidae (400-800 m) or Trachichthyidae (800-1200 m) to the South, but again there is a similarity between some groups. The family Alepocephalidae is dominant in the North (1200-2000 m), whereas further South, Dalatiidae showed a greater proportion in the catch. It is noteworthy the great abundance of Alepocephalidae in this area where no species of this family was recorded in assemblages described by others authors at the same depth. Likewise, the Macrouridae currently are less abundant. This absence of marked fish assemblages may be due to the high primary productivity in this ecosystem. Nevertheless, certain abundances can be related with the Cap Blanc upwelling but the absence of fishing activity in several depths and the overexploitation in others must determine as well the presence-absence data of some species or different groups. 103
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL5 P3
Fast growth hypothesis of European hake: an alternative approach in NW Africa C. Meiners1, L. Fernández2 and A. Ramos3 Universidad Veracruzana, Calle Hidalgo No. 617. Col. Río Jamapa, Boca del Rio, Veracruz, 94290, Mexico. Email:
[email protected] IEO, Centro Oceanografico de Malaga, Spain. 3 IEO, Centro Oceanografico de Vigo, Spain. 1 2
One of the key parameters to perform stock assessment and qualified management of fisheries is the age estimation of individuals. In spite of the importance of European hake fisheries for many countries, ageing hake still presents problems and this is a limiting factor for reliable stock assessment results. Historically has been considered as long-lived and slow growing species. However, recently tag-recapture experiments suggest that a high growth rate, around twofold than estimated before by otolith readings. In order to contribute to discussions and to clarify the growth performance of European hake, a novel approach using an alternative robust proxy to trace the length increments validation during the first three years is presented here. In previous works it has been established a strong relationship between European hake abundance and NAO index, lagged by time: 1 year with recruits to the fishery, 2 years with medium size hakes and 3 years with largest individuals. Taking this into account, we analysed the detailed catch based length distributions of European hakes, establishing the mean length for every length group and the length increment with the next length group after one year following the correlation time lag with NAO index. The observed growth during the first three years was compared to the growth expected from current models from different locations using the following equation: L2 - L1 = (L∞ - L1 )(1 - e-K(t2-Ct1)). The growth rate observed is consistent with fast growth hypothesis, multiplying by two or three the growth increments reported before to NW Africa. This means that European hake reach maturity between the first-second years of life. This is coherent with the high resilience of the species against fishing effort along this area. This growth rate is coherent as well with latitudinal gradient reported before between northern stocks (ICES area) and the Mediterranean and NW African stock.
Poster: PL5 P4
Spatial asynchrony in the reproductive condition of the anchovy (Engraulis ringens) associated with the sea surface temperature of the Humboldt Current system between 33° and 40°S M. Pedraza1,2, C. Gatica3, L. Cubillos1,2 and E. Navarro3 Laboratorio de Evaluación de Poblaciones Marinas-EPOMAR, Universidad de Concepción, cabina 9; casilla 160-C, Concepción, Chile. Email:
[email protected] 2 Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Chile. 3 Instituto de Investigación Pesquera- INPESCA, Talcahuano, Chile. 1
The fishery unit of anchovy (Engraulis ringens) off Central-South Chile (33° to 40°S), has been managed through an annual catch quota fractionated between the industrial and the artisanal sectors. Concerning other regulation measures, we remark the establishment of a closed season for the fishery, associated to the reproductive process, which was established for the whole area since 1998. However, new research and publications demonstrate located spatial differences on the reproductive process, in particular, because the main reproductive parameters depend of the demographic stock structure and environmental conditions. Thus, we want to review the reproductive condition of the Anchovy on a spatial-temporal frame during a complete annual cycle. For doing that, we used the gonadosomatic index (GSI), which allows us to determine regional (spatial) differences associated to sea surface temperature (SST) changes. We perform a monthly sampling monitoring of the reproductive condition of the resource Anchovy (Engraulis ringens) during 2007 from 33° to 40°S, using artisanal fleet catches. We analysed 250 georeferenced fishery launches and getting the following data for each captured specimen: total length (cm), total weight (g), gutted weight (g), ovary weight (g) and macroscopic stage of sexual maturity. The gonadosomatic index indicates a low reproductive activity of E. ringens during the first months of the year (February to March) for the study area. From June to October a latitudinal increase (from north to south) of the reproductive activity (increased GSI) of the anchovy was observed. Since September, there are no spatial differences in the reproductive condition of the resource for the whole study area, with high GSI values. This condition of spatial asynchrony of the GSI appears to be related to the latitudinal evolution of the SST, which should modifying the environmental conditions from north to south (from February to March) and with more stable values after the winter to summer transition (September to October) off Central-South Chile. 104
Eastern Boundary Upwelling Ecosystems Symposium
Poster: PL5 P6
On the dynamics of the common Octopus off Senegal: upwelling as an external forcing A. Solari1, E. Balguerías2, J. Castro1, D. Jouffre3, C. Bas4 and M. Thiaw3 1
Universidad de Las Palmas de Gran Canaria, IEO, Centro Ocean. de Canarias, AV. 3 de Mayo Nº 73 SC de Tenerife, Tenerife, 38005, Spain. Email:
[email protected]
2
IEO, Madrid, Spain.
3
Institut Universitaire de Pêche et d'Aquaculture (IUPA) de l'UCAII (Université de Dakar) & IRD, France.
4
Comité Superior de Investigaciones Científicas (CSIC), Spain.
The following material is a compilation of the preliminary results on Senegalese Octopus data (provided by the IRD) on age class/size (5=recruits; 6-14+=adult stock) numbers (monthly means) for years 19961999. In our theoretical groundwork, we propose the dynamics of exploited stock nucleii, populations and fisheries as a dynamical continuum (with multiple orbits of stability) governed by a variable (multivariate) carrying capacity. In this study, we take the preliminary steps to analyse aspects related to the (i) dynamical qualities of the population seen as a system, (ii) temporal evolution of numbers and (iii) the upwelling as an external forcing which may strongly contribute to shape the temporal evolution of the population/stock.
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P1+P2
Physics of the ocean and the atmosphere, and climate change influences on surface ocean-lower atmosphere exchanges
4 June, 10:15 (P1+P2 KNS1)
Coastal upwelling: a time-varying view E.D. Barton Departamento de Oceanografía, Instituto Investigaciones Marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain. Email:
[email protected]
The irregular but accelerating development in the understanding of the physical processes involved in coastal upwelling is reviewed. From early ideas of two-dimensional time-invariant upwelling under idealised winds to present-day concepts of a three-dimensional, constantly changing system forced heterogeneously, advances have followed in the wake of increasingly sophisticated observational and computational techniques that have provided unprecedented views of the ocean. Our present understanding is explored through case studies of surface forcing, physical processes near shore, upwelling and relaxation in the upper layers, horizontal and vertical exchanges, cold filaments and long term trends. The wider implications of our improved knowledge of the physical processes for the upwelling ecosystems are investigated in view of significant shortcomings that remain in our observational, analytical and predictive capabilities.
4 June, 10:45 (P1+P2 KNS2)
Dust in, gases out. Air-sea biogeochemical interactions in the tropical eastern North Atlantic D. Wallace IFM-GEOMAR, 49-431-600-4200, Düsternbrooker Weg 20, Kiel, Schlesweig-Holstein, 24105, Germany. Email:
[email protected]
The region between Mauritania and Cape Verde is heavily influenced by upwelling and also receives some of the strongest dust deposition in the World Ocean. The region is being intensively studied in the context of SOLAS through a combination of cruises as well as long-term observations at Cape Verde and campaigns at the Mauritanian coastline. The presentation will present an overview of recent results concerning: (1) airsea exchanges of gases; (2) the potential of atmospheric deposition to relieve nutrient limitation of carbon and nitrogen fixation. The presentation will attempt to identify the key questions and unresolved issues arising from these studies and outline opportunities to address them.
4 June, 11:15 (P1+P2 OP1)
Process-oriented numerical modelling studies of upwelling, currents and eddies in coastal boundary current regions M. Batteen1, H. Miller1 and A. Martinho2 1 2
Naval Postgraduate School, 833 Dyer Road, Monterey, California, 93943, USA. Email:
[email protected] Instituto Hidrografico, Portugal.
Ecosystems of the subtropical eastern boundary regions of the ocean (such as those off California, Peru and Chile, Southwest and Northwest Africa, and the Iberian Peninsula) are known for enhanced primary production due to processes such as upwelling which act to bring cooler and nutrient-rich water to the surface. The eastern boundary current (EBC) regions, particularly in the coastal region where the open ocean transitions to the eastern boundary, are complex dynamical systems where numerous interactions can exist between surface and subsurface currents and mesoscale features. In a hierarchy of increasing complexity of physical forcing mechanisms, we use the results of eddy-resolving, terrain-following EBC ocean circulation models to take a retrospective look at the generation mechanisms for classical features (e.g., coastal upwelling, surface equatorward currents, poleward undercurrents, meanders, eddies and filaments) of EBCs as well as some unique features of particular EBCs. For example, for the northern 106
Eastern Boundary Upwelling Ecosystems Symposium Canary Current System (NCCS), unique features include the presence of rias, separation of upwelling regimes, Mediterranean Outflow, Meddies and the Azores Current. The suite of physical forcing mechanisms systematically used includes local and remote wind forcing, wind stress curl, thermohaline gradients, coastline irregularities such as capes and bays, and bottom topography. Recent modelling advances, including new topography smoothing techniques which better preserve the inherently steep coastal bottom topography, are presented for EBC regions. The results of these process-oriented studies emphasise that numerical models of ocean circulation require important choices, which are both physical and numerical.
4 June, 11:30 (P1+P2 OP2)
Wind stress and sea surface temperature coupling in eastern boundary upwelling systems F. Colas1, X. Capet1, X. Jin1, J. Molemaker1, D.B. Chelton2 and J.C. McWilliams1 Institute of Geophysics and Planetary Physics, University of California, 405 Charles E. Young Dr, Los Angeles, CA, 90405, USA. Email:
[email protected] 2 College of Oceanic and Atmospheric Sciences, Oregon State University, USA. 1
A wind/SST empirical coupling, based on recent observations off California, is implemented in the Regional Ocean Modelling Systems (ROMS). High-resolution realistic regional numerical simulations of the Peru/ Chile (PCS) and the California (CCS) upwelling systems are investigated. Winds from large scale atmospheric models or satellites which are usual sources of model forcing do not resolve the nearshore dropoff which occurs in reality. The wind/SST feedback leads to reduced nearshore winds and warmer nearshore SST. The resulting nearshore wind profiles are close to the observed ones off California. This reduced coastal wind strength reduces the cold bias in nearshore SST's and significantly modifies the upwelling structure and the larger scale quasiequilibrium model solutions both for the PCS and the CCS. In addition, eddies, partly generated through instabilities of the nearshore upwelling currents, have been shown to be an important component of EBUS dynamics. More subtle effects of the wind/SST coupling can be expected on the mesoscale eddy activity through the upwelling structures modifications. Importance of the mesoscaleIGPP eddy activity in the EBUS and the influence of the wind/SST coupling are discussed and illustrated in term of heat balance and further possible upscaling effects.
4 June, 11:45 (P1+P2 OP3)
The Iberian Poleward Current around north and northwest Iberia M. Ruiz Villarreal1, C. Gonález Pola2, R. Sánchez3, P. Otero1, J. Manuel Cabanas4 and A. Lavín3 IEO, Centro Oceanográfico A Coruña, Muelle de Animas s/n. 15001 A Coruña, Galicia. Spain. Email:
[email protected] IEO, Centro Oceanográfico de Gijón, Spain. 3 IEO, Centro Oceanográfico de Santander, Spain. 4 IEO, Centro Oceanográfico de Vigo, Spain. 1 2
Autumn-winter shelf-slope circulation at the eastern boundary of the North Atlantic is dominated, like in other seasonal upwelling eastern boundary current (EBC) systems, by a poleward current: the “Iberian Poleward Current" (IPC). Around NW Iberia, the coastline changes orientation from south-north (Atlantic coast of the Iberian Peninsula) to west-east (southern Bay of Biscay) and this feature has an impact on dynamics that has not been investigated in detail. Data used in this study comprise hydrographic time series, cruises and moorings from Spanish monitoring time series and shorter term projects. Also data from the Spanish Deep Standard Sections will be presented: CTDO2, nutrients and currents from LADCP (from September 2004) have been measured twice a year since 2003 along three hydrographic lines: 43ºN, 8ºW and 3º 47'W from the shelf to open ocean. We will illustrate the main features of circulation and their variability and investigate the main physical processes involved in its generation and dynamics. The slope current is localised in autumn and winter over the slope in western and northern Iberia and advects warmer and saltier spicy subtropical Eastern North Atlantic Central Waters from southern origin (ENACWst). During events of upwelling favourable winds, the IPC seems to persist, although it apparently looses its surface expression and gets displaced offshore. This has implications for the spring transition in the area, when a change from prevailing downwelling conditions to upwelling conditions is observed. Spring upwelling pulses in the coastal zone at the setting up of upwelling season in spring might contribute to the displacement of subtropical waters offshore and to the weakening of the poleward flow. Anyway, larger-scale processes like the seasonal weakening of the meridional density gradient that sets up the poleward flow might have a significant contribution in this process.
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Eastern Boundary Upwelling Ecosystems Symposium On the Iberian west coast, the main forcing mechanism of this poleward flow is the large-scale meridional density gradient parallel to the slope, which is seasonally variable. Although this density gradient is the main forcing factor, a coupled response of the poleward slope flow to wind events through Ekman forcing and 829 interaction with the Ekman-induced shelf circulation is confirmed by numerical simulations. On the northern coast (southern Bay of Biscay), an along-shore pressure gradient is not present and the poleward flow is expected to decay by friction. We will discuss the role of upstream downwelling wind pulses, which can be more or less continuous or intermittent depending on the year, on the penetration of the IPC in the Bay of Biscay. We will discuss the possible impact of wind events and evaluate the importance of remote wind forcing on currents on the northern Iberian coast. A large interannual variability in the presence and intensity of the IPC current has been observed, and we will relate this observed variation to changes in the large scale density gradient, in winds and in mixed layer depth.
4 June, 12:00 (P1+P2 OP4)
Seasonal variability of the Canary Current system E. Mason1, F. Colas2, J. Molemaker2, A. Shchepetkin2, P. Sangrà1 and J.C. McWilliams2 1 2
Universidad de Las Palmas de Gran Canaria, Dept. de fisica, Camp. Tafira, Las Palmas 35017, Spain. Email:
[email protected] University of California, USA.
The equilibrium structure and dynamics of the Canary Current System (CaCS) in the eastern subtropical gyre of the North Atlantic are examined using the Regional Ocean Modelling System (ROMS). We employ three nested model grids, with respective horizontal resolutions of 10.0, 5.0 and 1.5 km that provide high mesoscale resolution, particularly in the vicinity of the northwest African upwelling and the Canary Island archipelago (CI). The large outer domain extends meridionally between 10º and 50ºN, and zonally from the western European and African continental boundaries to beyond the Mid-Atlantic Ridge at 35ºW. Mean seasonal forcing at the outer-domain open boundaries is provided by a new temperature and salinity climatology of the northeast Atlantic compiled at the Universidad de Las Palmas de Gran Canaria (Spain), and interpolated directly to the model grid using the DIVA spatial interpolation tool from the Université de Liège in Belgium. Boundary forcing for the embedded child grids is interpolated from each respective parent grid solution. COADS and the 25 km QuikCOW (QuikSCAT) wind stress climatology supply heat fluxes and momentum forcing, respectively, at the surface. Previous studies in other major upwelling regions have shown that mesoscale variability has an intrinsic character, so that it is present despite the lack of transient forcing. Our mean and seasonal equilibrium solutions display the main large- and mesoscale features that are observed in the CaCS: the Azores Current (AC) and associated frontal variability at 34ºN; the seasonal evolution of the upwelling along the Iberian and northwest African coasts, with the recurrent presence of offshore-extending filaments and fronts at several preferred locations; and generation of eddies at the CI. Eddy kinetic energy (EKE) levels computed from the model solutions are comparable to similar calculations from altimeter observations. In particular, we see elevated EKE along the axis of the AC, and in the downstream wake of the CI. The CI wake variability appears to be related as much to the welldocumented island-generated eddies and their interactions with coastal filaments, as to a lesser-known class of mesoscale eddy that periodically develops in the model in the region between Gran Canaria, Fuerteventura and the African coast, and is seen to propagate westward at ~26ºN. This phenomenon will be described elsewhere.
4 June, 12:15 (P1+P2 OP5)
Observed and modelled spring circulation of the northern limit of the Canary upwelling system during 2007 P. Otero1, M. Ruiz Villarreal1, P. Conde1, M. Cobas1, M. Varela1, G. González-Nuevo2 and M. Bernal3 IEO, Centro Oceanográfico A Coruña. Muelle de Ánimas s/n, 15001, A Coruña, Spain. Email:
[email protected] IEO, Centro Oceanográfico de Gijón, Spain. 3 IEO, Unidad de Cádiz. Universidad de Cádiz, Spain. 1 2
Spring is a characteristic oceanographic season with high relevance in the biological response of the system. During this season, the availability of light and nutrients favour phytoplankton growth and the spawn of many fish and shellfish species are known to be coupled to these spring blooms. Off North and Northwest Iberia, the northern limit of the Canary upwelling system, the spring transition is associated to the change 108
Eastern Boundary Upwelling Ecosystems Symposium of meteorological conditions from downwelling to upwelling favourable. The timing of the spring transition in relation to the period of the spring phytoplankton bloom and the spawning of different species is critical in determining growth and survival. This time depends on the strength of the prevailing oceanographic conditions during winter (river plumes, the presence of the poleward slope current, stratification, etc.) and the time of change of meteorological conditions to upwelling favourable. In the last years, the Instituto Español de Oceanografía (IEO) has been applying in the area a high resolution ocean model with full physics and high resolution meteorological forcing. The model aims at providing insight on circulation for ecosystem studies in support to the intense IEO ecosystem research in the area. In this sense, the main interest is on high resolution shelf and slope processes (upwelling, river plumes, slope currents). Since March 2007, coinciding with the spring pelagic-fisheries PELACUS0407 survey, the model was run daily to provide forecasts with a 72 hour horizon. This survey covered the oceanic shelf waters off the Iberian Peninsula and extending out to the southern French shelf. Conditions during the survey were upwelling favourable with low temperatures along most of the surveyed area. The influence of river runoff off the Cantabrian area, sometimes even far from the coast and next to the shelf break was observed. Areas of high primary production were found associated to the upwelling areas. Also, areas of high anchovy and sardine eggs density associated with freshwater plumes were observed. In this contribution, we will report on the insight on variability of circulation provided by this forecast model and the comparison with observations carried out during the survey. The model will help in the understanding of the spatial distributions of the observed ichtioplankton.
6 June, 12:30 (P1+P2 OP6)
Three-dimensional circulation in the NW African upwelling system V.M. Benitez-Barrios1, A. Hernández-Guerra1, J. Pelegri2, K.M.M. Lwiza3 and S. Hernández-León1 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Tafira Baja. Campus Universitario, Las Palmas 35017, Spain. Email:
[email protected] 2 Institut de Ciències del Mar, CSIC, Spain. 3 School of Marine and Atmospheric Sciences, USA. 1
An univariate spatial objective analysis of high-resolution hydrographic data, collected during early spring 2006 in the coastal upwelling system off NW Africa south of Canary Islands, provides a comprehensive view of the regional 3D circulation. A baroclinic southwestward jet is located in the channel between the eastern Canary Islands and the African coast, with maximum velocities of 18 cm s-1 at the surface decreasing to 3 cm s-1 at 400 db. The geostrophic transport of North Atlantic Central Water through this channel (referenced to 500 db) was 0.5 Sv. Downstream of the islands the jet meanders and induces mesoscalar eddies, as revealed in satellite images. The vertical motion associated to these eddies was diagnosed from the density and geostrophic velocity fields via the quasigeostrophic omega equation. The resulting vertical velocities ranged from -18 to 12 m day-1, with the largest absolute values corresponding to an anticyclonic eddy located south of Fuerteventura Island. Fluorescence shows a patchy distribution which appears to be a manifestation of the vertical velocity forcing and the eddy-eddy interactions.
6 June, 12:45 (P1+P2 OP7)
Interaction of physical, chemical and biological processes in atmosphere-ocean CO2 exchange in the Benguella upwelling L. Sørensen1, K. Richardson1,2, M.B. Christiansen3, J. Nissesn3, J. Bendtsen1, K.M. Hilligsøe1 and L. Mouritsen4 National Environmental Research Institute, Aarhus University, Denmark. Email:
[email protected] University of Copenhagen, Denmark. 3 Risø-DTU, Denmark. 4 Aarhus University, Denmark. 1 2
In October, 2006, en route from Accra to Cape Town, the Danish Galathea Expedition (www.galathea3.dk) traversed a region impacted by the Benguella upwelling. The position of the ship relative to the upwelling was monitored via on-line satellite imagery. Continuous measurements of both atmospheric and surface seawater pCO2 as well as surface water fluorescence characteristics (for estimating chlorophyll a content) were made. At selected stations, additional measurements including CTD profiles, photosynthetic carbon uptake rates, 109
Eastern Boundary Upwelling Ecosystems Symposium and nutrient concentrations at various depths in the surface layer were recorded. Finally, over part of the transect, a CTD mounted on an undulating platform recorded surface water characteristics. As expected, the surface upwelled waters were oversaturated with CO2 compared to the overlying atmosphere and concentrations exceeding 800 µatm were recorded. Immediately outside of the region impacted by upwelling, surface waters are initially oversaturated but, later, undersaturated with CO2 relative to the atmosphere. Here, we examine the interaction between biological and physical processes leading to the observed differences in CO2 distributions.
6 June, 13:00 (P1+P2 OP8)
Ocean/Atmosphere regional simulation along the Chilean coasts: sensitivity of the upwelling variability to the spatial resolution of the atmospheric forcing L. Renault1, D. Boris2, E. Vincent3 and Y. du Penhoat4 LEGOS, 14 avenue Edouard Belin, Toulouse, 31400, France. Email:
[email protected] IRD/IMARPE/LEGOS, Peru. 3 IRD/LOCEAN, France. 4 IRD/LEGOS, France. 1 2
Coastal upwelling regions are of special interest as they are the place of intense biological activity, mesoscale and submesoscale circulations which play a key role in the exchange of water properties between the open and coastal oceans. In this work, focus is given on the upwelling region off central Chile (26°S-36°S), which is driven by persistent low-level along-shore southerly winds. Satellite data, marine reports, and coastal in situ observations off central Chile indicate that those along-shore winds intensify at intraseasonal timescales leading to so-called Costal Jet events. Off central Chile, the southerly jet events occur year-round but are more frequent during the upwelling season in summer. The jet is characterised by an elongated maximum of surface wind speed (10m s-1) with its axis at about 150 km off the coast and a cross-shore scale of about 500 km. It is associated with a significant oceanic mesoscale variability that contributes to cross shore exchanges of heat, salt and biogeochemical material between the open and coastal oceans. Using high-resolution ocean (ROMS) and atmosphere (WRF) regional model, one year of atmosphere and ocean variability is simulated to investigate the sensitivity of the upwelling variability to the spatial resolution of the atmospheric forcing. In a first phase, the sensitivity of the surface wind and air-sea heat fluxes to the horizontal resolution of the atmospheric model is evaluated. Near the coast, increased resolution improves the realism of the cross-shore variability of the wind stress. The atmospheric fields simulated for different resolutions (90km, 30km, 10km) are then used as surface boundary conditions for the regional high-resolution ocean model. The results indicate a large sensitivity of the oceanic turbulent flow to the characteristics of the atmospheric forcing and suggest that air-sea coupling at mesoscale is a significant contributor to the upwelling variability in this region.
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P1+P2 Posters Poster: P1+P2 P1
Long-lived trace gases in the Mauritanian upwelling H. Bange, A. Freing, S. Gebhardt, A. Kock, A. Körtzinger and T. Steinhoff Forschungsbereich Marine Biogeochemie, IFM-GEOMAR, Düsternbrooker Weg 20, 24105 Kiel, Germany. Email.
[email protected]
Atmospheric and dissolved trace gases such as carbon dioxide, nitrous oxide and methane were measured continuously in the oceanic and atmospheric boundary layers in the Mauritanian upwelling area. The measurements were part of the German SOPRAN (Surface Ocean PRocesses in the ANthropocene) project and took place during several cruises from 2005 to 2008. The eastern tropical North Atlantic Ocean is a site of contrasting oceanic regimes, which include high productive coastal upwelling areas along the Mauritanian coast and oligotrophic open ocean regions. Thus the eastern tropical North Atlantic Ocean is an ideal site to study the air-sea exchange of traces gases in view of contrasting biological and physical processes, which determine the air-sea gas exchange. Coastal upwelling areas such as the Mauritanian upwelling are sites of significantly increased emissions of trace gases: maximum surface concentrations of carbon dioxide and nitrous oxide were observed during the upwelling season in March/April 2005 whereas during the non-upwelling season in July/August 2006 the surface concentrations of both gases were close to the equilibrium concentrations. Methane surface concentrations were significantly enhanced during the upwelling season in February 2007. Biological and physical processes influence the carbon dioxide distribution in the surface layer whereas the surface distributions of nitrous oxide and methane are determined only by physical processes. Therefore, a comparison of carbon dioxide measurements with nitrous oxide and methane measurements could reveal new insights into the mechanism of air-sea gas exchange.
Poster: P1+P2 P2
On the influence of the Galapagos Islands on the Humboldt Current system J. Boucharel1, G. Eldin1, Y. Du Penhoat1 and V. Echevin2 1
LEGOS, 14 avenue Edouard Belin, Toulouse 31400, France. Emai:
[email protected]
2
LOCEAN, France.
Recent studies have shown that water masses which compose the poleward Peru-Chile Undercurrent (PCUC) and the equatorward Peru Coastal Current are influenced by the variability of the Equatorial Under Current (EUC) and of the South Equatorial Current. Other modelling studies emphasised that EUC intensity is strongly affected by the Galapagos Islands (GI) reducing the eastward flow and dampening Tropical Instability Waves. Thus, the archipelago appears to be a key element connecting the Equatorial Pacific and the Humboldt Current system. A ROMS (Regional Oceanic Model System) model configuration was designed to address the role of the small scale topography of the Galapagos Islands on the dynamics of the area. The AGRIF (Adaptive Grid Refinement in Fortran) grid refinement software, implemented into the ROMS regional ocean model, leads to generate nested grids with a spatial resolution up to 1/18°. In the present work, “two-way” feedbacks between the “parent” grid at 1/6° resolution and the “child” grid (1/18°) implemented in the GI area are enabled. The main investigated questions were how this fine bathymetry and model spatial resolution impacts seasonal variability, meso-scale dynamics in the region and the tracking of EUC/PCUC pathways. The influence of these islands on the equatorial waves propagation is also diagnosed in order to document the role of ENSO cycles on the surface and sub-surface water properties off South America coast. Numerical experiments will be confronted to the TAO mooring data (95°W, just west of GI) and to satellite altimetry in order to validate our downscaling procedure. 111
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P1+P2 P3
Mesoscale dynamics in the north Humboldt Current system - a comparison with the three other upwelling systems A. Chaigneau1, G. Eldin2 and C. Grados3 IRD-LOCEAN and IMARPE, Esquina general Gamarra y Valle, Callao, Peru. Email:
[email protected] IRD-LEGOS, Toulouse, France. 3 Instituto del Mar del Peru, Peru. 1 2
Relatively little is known about coherent vortices in the eastern South-Pacific (ESP) along the Peruvian coast, even with regard to basic facts about their frequency of occurrence, longevity and 3-dimensional structure. This study addresses these issues using nearly 15 years of relatively high-resolution satellite altimetry measurements and vertical profiles from ARGO buoys. Then, a brief comparison of the eddy statistics in the 3 other upwelling systems (California, Canary, Benguela) is provided. We first investigate vortices off Peru using more than 20,000 mesoscale eddies identified by the winding-angle method. Coherent eddies, characterised by a high ratio of vorticity to deformation rate, are typically formed along the coast and propagate westward at 3-6 cm s-1. The vortices have a mean radius of 80 km, increasing northward, and are most frequently observed off of Chimbote (9ºS) and south of 15ºS. The mean eddy lifetime is about one month, but if they survive at least two months, the probability for surviving an additional week (or month) is constant at 90% (or 67%). Anticyclonic eddies tend to propagate northwestward whereas cyclonic vortices migrate southwestward. In general, cyclones and anticyclones are similar, except for eddies surviving at least 6 months. In this case, after a similar 3-4 months of radius and amplitude growth, amplitudes (or sizes) decay particularly rapidly for anticyclonic (or cyclonic) eddies. In terms of intensity, cyclonic eddies show a rapid decay during the first 3 months before arriving at a quasi-constant value, whereas anticyclones exhibit steady decline. We then examine the eddy temporal variations in the ESP at seasonal and interannual scales in the “coastal” region favourable to the formation of energetic mesoscale structures. On seasonal scales, eddy activity is maximal in fall and minimum in spring. At an interannual scale, the eddy activity index was maximal during the strong El Niño of 1997-1998 but another strong maximum of eddy activity also occurred late in 2004. These temporal variations are probably associated with the intensification of the upwelling thermal front and with the passage of coastal-trapped waves which generate baroclinic instabilities. Using vertical temperature and salinity profiles from ARGO buoys, we estimate the typical vertical structure of both cyclonic and anticyclonic eddies of the ESP. Available heat and salt anomalies (AHA and ASA respectively) are then computed relatively to the World Ocean Atlas of 2005. Integrating over the first 1000 m, mean AHA of 7.3×108 J m-2 and ASA of 3.3 kg m-2 are associated with anticylonic eddies. The corresponding values for cyclonic vortices are of -6.8×108 J m-2 and -15.4 kg m-2 respectively. Integrating over the radial surfaces of the eddies, the total heat anomaly for a typical anticyclonic (or cyclonic) eddy of the HCS is then 6.7×1018 J (or -7.7×1018 J), with a total salt anomaly of 4.9×1010 kg (-1.8×1011 kg). Finally, the same methodology is applied in the 3 other upwelling systems to compare eddy characteristics, their formation sites and propagation patterns in both regions. This study provides crucial information on mesoscale dynamics which can have important impacts on the biological activity.
Poster: P1+P2 P4
Interannual modifications in dynamics and shape of boundary between intermediate waters of northern and southern origin in area of the Canary ipwelling in 1994-2007, due to ocean level and NAO P. Chernyshkov and I. Gleza AtlantNIRO, Kaliningrad, 236000, Russia. Email:
[email protected]
In the area of the Canary upwelling, the bioproductivity of the waters in the photic zone is significantly influenced by the predominance of Northern Atlantic (NACW) or Southern Atlantic (NACW) origin waters in intermediate oceanic layers. The positions and shapes of boundary between those waters are determined from results of 21 oceanographic surveys in warm and cold seasons of every year. The features obtained were compared to NAO and anomalies of the ocean level by altimetry data. The positive NAO values correspond to a decrease in ocean level and SACW predominance, negative values correspond to the 112
Eastern Boundary Upwelling Ecosystems Symposium reverse picture. The shape of the boundary between 100-700 m underwent significant changes. Reliable correlations of such modifications with ocean level and NAO were not found.
Poster: P1+P2 P5
A review of upwelling Indices and implementation in the Mercator-Ocean operational analyses and forecast systems L. Crosnier1, M. Drévillon2 and F. Soulat1 1 2
Mercator Ocean, 8-10 rue Hermes, parc technologique du canal, 31520 Ramonville St Agne, France. Email:
[email protected]. Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique, France.
Mercator-Ocean is operating a large range of operational systems able to analyse and forecast the ocean state including the 3D ocean temperature, salinity and currents at various horizontal and vertical resolutions. Mercator-Ocean is currently working on defining pertinent environmental indicators as ocean climate or regional indicators using the Mercator-Ocean operational systems, within the GMES framework (MERSEA, BOSS4GMES and MyOcean). We first briefly present the Mercator-Ocean operational suite of Ocean Forecast Systems (OFS). The description of the ocean at Mercator-Ocean will improve in the fore coming years by using more sophisticated data assimilation techniques, and a more realistic ocean model with improved parameterizations and higher spatial resolution (1/12°). We then present a review of the existing upwelling indices which can be sorted into 3 types: i) Upwelling indices based on wind data or sea surface pressure fields, ii) Upwelling indices based on the 3D velocity fields, and iii) Upwelling indices based on sea surface temperature (SST). In this presentation we will be dealing with the 2 last indices. Indeed, hydrodynamic models as the Mercator-Ocean systems i) provide an opportunity to directly assess the upwelling process through the use of realistic simulated 3D velocity or SST fields and ii) provide ocean forecast of the upwelling event two weeks in advance. Hence, upwelling indices using the 3D velocity or SST information have been computed in the Atlantic, Pacific and Indian Oceans. In the Atlantic basin, upwelling indices are computed from 50°N down to 34°S in the Mercator-Ocean Global ¼º OFS assimilating Sea Level Anomaly, SST and in situ profiles. Upwelling events are clearly identified. We will present results that highlight the usefulness of the Mercator-Ocean OFS in order to characterize and detect 2 weeks in advance upwelling events. Operational monitoring of upwelling events is important for various users such as fisheries activity or local authorities.
Poster: P1+P2 P6
Rossby waves interannual variability near the Benguela upwelling system E. Gutknecht1, I. Dadou1, G. Charria2 and V. Garçon1 Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France. Email:
[email protected] 2 National Oceanography Centre, United Kingdom. 1
Sea Level anomalies (SLA) and Sea Surface Temperature, deduced from remotely sensed data, have allowed the detection of baroclinic Rossby waves in the South Atlantic Ocean. Several studies have shown that these waves have a distinct signature on surface chlorophyll concentrations in this region. The present study focuses on the eastern part of the South Atlantic Ocean at mid-latitudes. The interannual variability of these waves, especially in relation with the eastern boundary in the Benguela upwelling system, is investigated. The chlorophyll concentrations (SeaWiFS data from 1998 to 2006) and the Sea Level Anomalies (combined TOPEX/ERS/JASON data from 1992 to 2006) are analysed using a wavelet method. Wavelengths (around 500 km), associated with the first baroclinic mode of Rossby waves, are extracted both from SLA and chlorophyll concentrations. Westward propagations on longitude/time diagrams of SLA show an interannual variability of the amplitude and of the number of generated waves on the eastern part of the basin near the Benguela Upwelling region. This variability, which is not detected in the chlorophyll concentrations, highlights particular years in the wave generation processes. This interannual variability seems to be linked with the major oscillations in this area: Benguela Niño and Atlantic Niño. 113
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Poster: P1+P2 P7
The Panama Bight upwelling dynamics A. Devis-Morales1, R. Montoya2 and W. Schneider1,2 1 2
Departamento de Oceanografía, Casilla 160-C, Cabina 5, Universidad de Concepción, Concepción 4070386, Chile. Email:
[email protected] COPAS, Universidad de Concepción, Chile.
The Panama Bight is one of the most dynamic upwelling ecosystems in the eastern Pacific Ocean due to the seasonally changing wind field caused by the migration of the Intertropical Convergence Zone (ITCZ) and the occurrence of interannual El Niño Southern Oscillation (ENSO) events. To determine its seasonal and interannual upwelling variability, satellite and in situ oceanographic data were used. Surface currents from altimetry data (AVISO-MADT), Reynolds and Smith sea surface temperature (SST) and QuikSCAT wind field data were seasonally averaged and compared with the strong El Niño (April 1997 to June 1998) and La Niña (October 1998 to Mach 2000) events. Oceanographic cruises made by the Colombian Navy during February 2002, June 2001, May 1998 and May 1999 were chosen to represent typical winter, summer, El Niño and La Niña conditions, respectively. The upwelling process is intense during boreal winter, when the ITCZ is in its southernmost position; the northeast trades prevail, and high pressure systems over the Caribbean Sea force strong winds through the Panama Isthmus favouring an intense and narrow wind jet, which blows offshore the Gulf of Panama producing a basinwide cyclonic gyre and intense upwelling east of 85ºW. Prominent oceanographic features including: the relatively cold (<26ºC), saline (>32.6), nutrient-rich, high chlorophyll concentration (>15mg m-3) and of phytoplankton abundance of the surface waters; the shoaling of the thermocline towards the east (20 m) and the distinct thermal dome, are coincident with positive wind curl evidencing the very active winter upwelling dynamics. Enhanced biological productivity during this season could lead to important fisheries such as yellowfin and skipjack tuna. In boreal summer when the ITCZ is in its northerly position and the cross-equatorial southeast trades activate the monsoon circulation, the cyclonic gyre is reduced in magnitude and restricted to the coastal region and SST is warm (27° - 29°C) and zonally homogeneous everywhere to the north of 2°N. Cool (<26.5°C) and saline (>33) waters south of this latitude evidence the intensification of the equatorial Cold Tongue which strengthens the South Equatorial Current (SEC). The surface layer is low in chlorophyll and nutrients, and the thermocline is deeper (50 m) due to a warm and thick isothermal surface layer. During El Niño, SST anomalies (departures from the 1970-2004 average calculated from 56 oceanographic expeditions made by the Colombian Navy) reached +3°C; surface salinity is low, and the nutrient-poor upper waters reflect the low phytoplankton abundance and low chlorophyll (<3 mg m-3) concentrations and of diatoms populations. Dissolved oxygen concentrations are highest (4.2 ml L-1) allowing the occurrence of specific dinoflagelates species (related to tropical and nutrient-poor environments) identified as useful El Niño indicators. During La Niña, SST is low (-1°C anomaly); surface salinity increases and the surface dissolved oxygen concentration is reduced (2 ml L-1). However, the high nutrients content in the upper layer allows an increase in the phytoplankton productivity and in the chlorophyll concentrations (4.6 mg m-3), favouring the occurrence of diatoms (some species are exclusive to La Niña events) and the reduction in the dinoflagelates abundance.
Poster P1+P2 P8
Average circulation and seasonal cycles of hydrographic conditions offshore central Chile by means of ROMS D. Donoso1,2, F. Colas3 and W. Schneider1,2 COPAS, barrio universitario s/n, Cabina 5, Universidad de Concepción, Concepción 4070386, Chile. Email:
[email protected] Departamento de Oceanografía, Universidad de Concepción, Chile. 3 Institute of Geophysics and Planetary Physics, University of California, USA. 1 2
Here we present a numerical seasonal simulation of oceanic variables offshore central Chile by means of the Regional Ocean Modelling System (ROMS, Shchepetkin and McWilliams, 2005). Our study focuses on the eastern South Pacific Ocean off central Chile, confined by 32-40°S and 71-80°W. The model is initiated with Simple Ocean Data Assimilation (SODA) temperature and salinity climatologies, uses ETOPO-2 bathymetry, and is forced by mean monthly winds (QuickScat), surface heat fluxes and evaporation minus 114
Eastern Boundary Upwelling Ecosystems Symposium precipitation balance (COADS). We choose a horizontal resolution of 5 km, a time step of 15 minutes, and 30 vertical Sigma levels. The model output consists of 3-dimensional fields of temperature, salinity, velocity, sea surface height and other variables. After a spin-up period of 2 years the model was run for 6 years from which seasonal climatologies were computed. The hydrographic results then were validated with oceanographic measurements stemming from ARGO, WOCE, Blue Earth Global Expedition (BEAGLE, Uchida and Fukasawa, 2005), and World Ocean Atlas 2001 climatologies (WOA01). The model reproduces well the annual mean state and the seasonal cycles of the regions oceanographic variables. ROMS’s horizontal and vertical temperature and salinity pattern are in good agreement with observations, although slight differences were noted in absolute values and position of fronts. General circulation results shows an amplified equatorward flowing current, the Humboldt Current, with surface velocities in the order of 8 cm/s. Closer to the coast the current is only shallow but deepens offshore to more than 500 m, with of course decreasing speeds. Equatorial Subsurface Water, located along the upper continental slope, flows poleward, as confirmed by several publications, with flow speeds being in the order of 4-6 cm/s, which, however, seems to be an underestimation. Below the Equatorial Subsurface Water, along the coast a narrow equatorward flowing current of about 2 cm/s is observed, which also is well documented in the literature. The general flow pattern along 32.5°S, associated with the subtropical gyre circulation and the extention of water masses is well reproduced by our simulation.
Poster: P1+P2 P9
Vertical chlorophyll profile impact on mixed layer temperature and nitrate concentration O. Duteil1, Y. Dandonneau1, A. Lazar1 and I. Wainer2 1 2
LOCEAN, Tour 45-55, 4eme étage , 4 place Jussieu, Paris 75005, France. Email:
[email protected] Instituto Oceanográfico da Universidade de São Paulo, Brazil.
The role of chlorophyll in the absorption of energy in the upper ocean and its impact on ocean temperature has been studied by various authors using Ocean Global Circulation Models (OGCMs). It has been shown that chlorophyll has a significant impact on physical parameters, such as sea surface temperature (SST) and Mixed Layer (ML) depth. However, very few studies have explicitly considered the impact of the Deep Chlorophyll Maximum (DCM) on these parameters. The DCM is nevertheless a ubiquitous feature and is often located a few meters below the ML in tropical oceans. Thermal Domes and eastern boundary upwelling systems under weak upwelling conditions present such a structure, with a very shallow DCM (20-30m). Its impact is then believed to be maximal in these regions. We compare two experiments conducted with a 1D vertical transport model derived from OPA NEMO. This model has been coupled with the PISCES biogeochemical model. The resolution is 1 m in the upper 100 m. The model has been forced by the climatological conditions of the Guinea Dome, where a shallow and strong DCM is present yearlong. The CST experiment is characterised by a vertically constant chlorophyll concentration whereas the CPL experiment differs by the presence of a DCM at depth. In CPL, the DCM is responsible for an increase of the ML temperature by 0.3°C in autumn, correlated with a diffusion increase in the ML. The CPL seasonal thermocline is indeed less stratified and entrainment is enhanced. Biogeochemical tracers are also impacted as nitrate concentration rise in the CPL ML in autumn (increase by a factor 10) and may favourise development of phytoplankton blooms in spring, particularly in subtropical regions.
Poster: P1+P2 P10
The Strait of Gibraltar, an upwelling cutting down the upwelling F. Echevarría1,2, D. Macías2 and C. García2 Centro Andaluz de Ciencia y Tecnología Marina, Universidad de Cádiz, Campus de Río San Pedro, Puerto Real, Cádiz, 11510, Spain. Email:
[email protected] 2 Departamento de Biología, Universidad de Cádiz, Spain. 1
The Strait of Gibraltar communicates the Atlantic Ocean with the Mediterranean Sea through a double current with water of high density entering the Atlantic basin. This Mediterranean outflowing water (MOW) deepens to about 1000 m in the Gulf of Cádiz and its signature influence the whole North Atlantic, with important effects on the general thermohaline circulation. The exit of MOW through the Strait of Gibraltar 115
Eastern Boundary Upwelling Ecosystems Symposium feeds a downwelling of water entering the Atlantic at a latitude of 36ºN, just in the region of eastern boundary upwelling system (EBUS) of the North Atlantic, indeed this feature cuts down the system in two parts: Iberian upwelling in the North and North African upwelling in the south. None of the other EBUS present this kind of discontinuity. On the other hand, a pulsating upwelling event happens within the Strait of Gibraltar itself. The combination of bottom topography in the region of Camarinal sill and the hydrodynamics allows important vertical movements of water and the generation of a sequence of horizontal convergences-divergences when arrested waves that stand in the area during 3-4 hours at each tidal cycle are formed. These processes and the later liberation of these structures towards the Mediterranean imply a pulsating upwelling of MOW in the Strait. So, the strait of Gibraltar is cutting the main upwelling system of the eastern boundary but is itself an intermittent upwelling. There are important differences between both upwelling systems: (1) they have very different temporal and spatial scales, (2) the upwelling of the Strait is forced by tides, while the main forcing in EBUS is wind, and (3) the upwelled water flows toward the east in the Strait, feeding surface waters of the Alborán sea, while upwelled waters in EBUS flows offshore toward the west. This presentation analyses the role of the Strait hydrodynamics as a cut down of the EBUS while appearing to be a mirror after generating other upwelling which flows in the opposite direction.
Poster: P1+P2 P11
Observations of the fine structure of the Peruvian upwelling: preliminary results from the ‘Filamentos’ cruise G. Eldin1, A. Chaigneau2,3, B. Dewitte1,3, V. Echevin2, C. Grados3, Y. du Penhoat1, L. Renault1, L. Vásquez3 and J. Ledesma3 LEGOS, 14 Avenue Edouard Belin, Toulouse 31400, France. Email:
[email protected] LOCEAN, France. 3 Instituto del Mar del Peru, Peru. 1 2
The Filamentos cruise was carried out in February 2008 in the Peruvian coastal upwelling system on board the Peruvian research vessel Jose Olaya Balandra, in order to document the mesoscale structures of the system dynamics and the associated biological response. For that purpose, a series of 100 nm sections across the continental shelf and slope was carried out, providing a high resolution sampling of physical and biogeochemical parameters on the water column, as well as acoustical biomass estimates. This paper presents preliminary results of that cruise in terms of hydrology and dynamics. The general climatic context of the cruise is first exposed: remotely sensed data allow characterisation of the current La Niña conditions, with abnormally cold and salty surface waters, and these anomalies are quantified by comparison with available climatologies. Given the space and time scale of mesoscale structures in the area, the 15-day Filamentos cruise can be considered as a synoptic snapshot of the hydrology (temperature, salinity, dissolved oxygen): fine scale details of these parameters across and along the shelf are described and quantified. ADCP (Acoustic Doppler Current Profiler) data obtained from surface to 500 m depth provide details on horizontal currents fields, which are compared with the mean circulation of the study area, characterised by the Chile-Peru Current, and the Peru-Chile Undercurrent. Estimates of both geostrophic and ageostrophic components of the circulation are obtained and discussed. Combining hydrological and ADCP data also allows an evaluation of the vertical component of the velocity, a key element in the dynamics of the upwelling, which can not otherwise be measured. Preliminary results from a modelling platform, involving a regional ocean circulation model (ROMS/PISCES) coupling dynamic and biogeochemical processes and forced by WRF regional atmospheric forcing during the period of the cruise are also presented. 116
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Poster: P1+P2 P12
Contribution of oxygen minimum zone waters to the coastal upwelling off Mauritania M. Glessmer, C. Eden and A. Oschlies IFM-GEOMAR, Mirjam Glessmer, Düsternbrooker Weg 20, 24105 Kiel, Germany. Email:
[email protected]
A special feature of today’s marine oxygen fields is the presence of extended oxygen minimum zones in the tropical oceans. These areas can be of particular biogeochemical relevance whenever oxygen levels fall low enough to allow for anaerobic conversion of fixed nitrogen, a major nutrient essential for biological production, into gaseous N2 not accessible to most organisms. Thereby waters emerging from oxygen minimum zones may exhibit low NO2:PO4 ratios and high concentrations of N2O, which is a potent greenhouse gas. For an assessment of associated physical-biogeochemical feedbacks in the climate system, it is essential to understand where the oxygen minimum waters go to, what their residence times are, and how sensitive their pathways are to changing climatic conditions. In a model trajectory study, simulated ’floats’ are deployed in the oxygen minimum zone which is located in 200 to 300m depth off West Africa. They are advected using three-daily velocity fields from a 1/12 degree North Atlantic model. It was found that water from the oxygen minimum zone contributes to less than 5% of the upwelling off West Africa and that its water is distributed mainly in a diffusive way rather than in distinguishable currents. In order to identify the source regions and supply routes to the upwelling off West Africa, floats are released in the upwelling region and then numerically integrated backwards in time. With this method, source regions of the upwelled water masses are investigated and found to be mainly the North Equatorial Undercurrent for water masses upwelled south of 22±N and the Azores Current for waters upwelled north of 22±N. In a dye tracer release experiment the results of the purely advective floats were compared with a passive dye tracer subjected to both advection and diffusion.
Poster: P1+P2 P13
Anomalous cooling in the Northern Gulf of California F. Gómez-Valdivia and A. Parés-Sierra Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Km. 107 Carretera Tijuana – Ensenada, Ensenada B.C., Ensenada B.C. 22860, Mexico. Email:
[email protected]
In the Gulf of California, the coolest surface waters, all year-round, are between 28°N and 30°N. The anomalous cooling of the sea surface, which makes the region one of the most biologically diverse and productive places in the world, is a manifestation of constant upwelling brought about by the presence of large islands and sills, in combination with strong tidal currents. The Regional Ocean Modelling System (ROMS) is used to identify the relevant factors involved in the presence of this latitudinally anomalous cooling. We are particularly interested in the relevance of tides and bathymetry through tidal mixing and pumping. Heat balances have been calculated using ROMS with and without tidal forcing to isolate the different mechanisms.
Poster: P1+P2 P14
A regional climatology of the north Humboldt Current system off Peru C. Grados1, A. Chaigneau2, A. Harang3, L. Vásquez1, J. Ledesma1, J. Habasque3, B. Dewitte2, V. Echevin2, G. Eldin4 and A. Bertrand5 Instituto del Mar del Peru, Esq. Gamarra y Gral Valle s/n, Chucuito, Callao, Callao 51, Peru. Email:
[email protected] IRD-LOCEAN, France. 3 IRD, France. 4 IRD-LEGOS, France. 5 IRD-ECOUP, Peru. 1 2
A 3-dimensional, high-resolution, regional climatology of the North Humboldt Current System (NHCS) off Peru is presented. This new climatology constitutes an important tool for initializing / validating regional numerical models. The methodology is based on a four-dimensional ocean interpolation scheme using locally weighted least square fitting, as developed by Dunn and Ridgway [2001] and Ridgway et al. [2002] in the Australian Seas. The method is applied to both historical hydrographic profiles from 1960-2007 and 117
Eastern Boundary Upwelling Ecosystems Symposium ARGO buoys data from 2000-2007 to form a seasonal climatology of temperature, salinity and oxygen along the Peruvian coasts. In order to match the data density and produce gridded estimates with maximum resolution, the smoothness scale of the mapping method is adaptive and the horizontal resolution varies from 1/10º in the offshore waters to 0.5º in the open ocean. The resulting maps depict interesting smallscales coastal properties and clear distinct upwelling centers. Geostrophic currents relative to 500 m depth are also computed from the density field, highlighting new circulation features, which are compared to those obtained in recent high-resolution numerical simulations of the NHCS. This study aims to provide a contemporaneous view of the circulation and the water masses characteristics along the Peruvian coasts at seasonal scales, and clearly shows the lack of resolution of the commonly used climatologies. The comparison of our results with climatologies of other upwelling systems also help to understand the differences in physical dynamics and productivity between both regions related to the size of the continental shelf and the presence of an oxygen minimum zone.
Poster: P1+P2 P15
CO2, O2 and nitrogen loss in the Benguela upwelling system using biogeochemical modelling and in situ data E. Gutknecht1, I. Dadou1, V. Garçon1 and L. Sørensen2 Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France. Email:
[email protected] 2 National Environmental Research Institute, Department of Atmospheric Environment, Aarhus University, Denmark. 1
Uncertainties exist in our understanding of the biogeochemical cycles of nitrogen and carbon, two key cycles for climate regulation via both greenhouse gases: N2O and CO2. Unknowns remain in the nitrogen sources within the oligotrophic gyres. In the Atlantic Ocean, the nitrogen source by coastal upwelling could be important due to the narrow extension of this basin. The role of the Benguela upwelling system as a nitrogen source for the open ocean, via the turbulent instabilities and filament structures enriched in chlorophyll (possible sink of CO2), is still to be investigated. The loss of nitrogen by denitrification or anammox with N2O and H2S gas emissions can also occur in this very productive zone in which the dissolved oxygen concentration may get very low. As a first step, a simple 1D biogeochemical model NPZDDON, with N (dissolved inorganic nitrogen), P (phytoplankton), Z (zooplankton), D (detritus) and DON (dissolved organic nitrogen) is used. Several state variables and processes are added for example both biogenic gases oxygen (O2) and carbon dioxide (CO2) as well as the nitrogen loss (denitrification, anammox) in this minimum oxygen zone, in order to simulate the ecosystem evolution. Two data sets are used to validate the biogeochemical model of the marine carbon, nitrogen and sulfur cycles in the Benguela upwelling area. This model set up for the area is compared with data of CO2, O2, chlorophyll a, nutrients, from the R/V Meteor Expedition M57 (February-April 2003) and from the Danish Galathea Expedition collected in the Benguela area (October 2006). N and C budgets as well as sensitivity analysis are performed to understand the CO2 and O2 regulation, and dynamics of the nitrogen loss. This will lead to improve our knowledge of the processes controlling the air-sea gas exchange of specifically CO2 in this upwelling area. This is critical for assessing the role of the coastal ocean in regulating atmospheric concentrations of greenhouse gases.
Poster: P1+P2 P16
Nitrous oxide in the Mauritanian upwelling A. Kock1, A. Freing1, S. Gebhardt2 and H. Bange1 1 2
Forschungsbereich Marine Biogeochemie, IFM-GEOMAR, Düsternbrooker Weg 20, 24105 Kiel, Germany. Email:
[email protected] Luftchemie, MPI fuer Chemie, Germany.
Nitrous oxide acts as an important greenhouse gas in the atmosphere and is known to contribute significantly to global warming. About 30 % of the annual nitrous oxide emissions are of oceanic origin, where nitrous oxide is formed as a byproduct or an intermediate in the marine nitrogen cycle during nitrification and denitrification, respectively. Oceanic nitrous oxide emissions show a high regional variability. Shelf regions and coastal upwelling areas are known to be hot-spots of nitrous oxide emissions. 118
Eastern Boundary Upwelling Ecosystems Symposium In order to investigate the role of the eastern tropical North Atlantic Ocean as a source of atmospheric nitrous oxide, measurements of dissolved and atmospheric nitrous oxide were performed during four cruises in the Mauritanian upwelling region in March/April 2005, July/August 2006 and February 2007 and 2008. These measurements were part of the German SOPRAN (Surface Ocean Processes in the Anthropocene) project. Surface concentrations of nitrous oxide were measured continuously during the Poseidon cruise 320/1 in 2005 and the Meteor cruise 68/3 in 2006. In total, more than 700 measurements of dissolved nitrous oxide in the upper ocean layer were performed. Nitrous oxide concentrations were generally close to equilibrium in the open ocean waters which were not influenced by coastal upwelling. Upwelling influenced water masses were found above the shelf break during the 2005 cruise showing enhanced nitrous oxide concentrations with maximum values of about 13 nmol L-1. During the Meteor cruise 68/3 coastal upwelling was found only north of 20°N where upwelling is supposed to take place throughout the year. In this area enhanced nitrous oxide concentrations were measured with maximum concentrations of about 11 nmol L-1. South of 20°N nitrous oxide concentrations were close to equilibrium. Depth profiles of dissolved nitrous oxide were measured during both the Meteor cruise 68/3 in 2006 and the Poseidon cruise 348 in 2007. Measurements were performed during a transect along 18°N from 25°W to 16°W and close to the Mauritanian shelf in the region between 17°N and 20°N. The depth profiles showed a pronounced subsurface maximum between 100 and 700 m in the open ocean waters during both cruises. Near the shelf two subsurface maxima were observed, with a minimum at about 300 m, indicating nitrous oxide consumption in the oxygen minimum zone below the upwelling-induced high productivity area off the Mauritanian coast. Our results indicate that the Mauritanian upwelling area is a strong source of nitrous oxide to the atmosphere. We will present a regionally and temporally adjusted emission estimate for the Mauritanian upwelling.
Poster: P1+P2 P17
Impact of small scale structures on a coastal upwelling ecosystem C. Lathuiliere, V. Echevin, M. Lévy and G. Madec LOCEAN, case 100, 4 pl. Jussieu, 75252 Paris cedex, Paris, 75252, France. Email:
[email protected]
It is now quite well established, that in most cases in the open ocean, the primary production is favoured by mesoscale and submesoscale circulation. The purpose of this study is to investigate the impact of small scale (including mesoscale and submesoscale) dynamics in the case of an eastern boundary upwelling system. Our approach consists in comparing simulations including and excluding such a dynamic. In order to do that, an idealised model of coastal upwelling is built. It is based on the primitive-equations ocean circulation model OPA coupled to the 6-components ecosystem model LOBSTER. The model mimics an infinite uniform coast with north-south cyclic boundary conditions. First, we show that this coastal upwelling model is realistic both for mean state and small scale structures. Eddies and perturbations compatible with the traditional baroclinic instability of the coastal jet are observed. Second, we emphasise the impact on the phytoplankton concentration and on the offshore export of nutrient, phytoplankton and nitrogen. A phytoplankton peak is observed near the shore as a response to coastal upwelling in both simulations. The distance of this peak from the shore is increased by the presence of small scale. The phytoplankton concentration within 100 km from the coast is shown to be reduced in presence of small scales structures. To understand the change in the biogeochemical cycles, the fluxes between nutrient, phytoplankton and zooplankton and the downward export of organic mater are closely examined. To further examine the role of small scale, we investigate the role of the eddy fluxes. Advective fluxes are decomposed into mean state fluxes and eddy fluxes in the run with small scales structures. 119
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Poster: P1+P2 P18
Water masses, currents and diapycnal mixing in the Cape Verde Frontal Zone A. Martínez-Marrero1, A. Rodríguez-Santana1, A. Hernández-Guerra1, E. Fraile-Nuez2, F. López-Laatzen2, P. Vélez-Belchí2 and G. Parrilla2 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Edif. Ciencias Básicas, Campus Universitario Tafira, Las Palmas de Gran Canaria, Las Palmas, 35017, Spain. Email:
[email protected] 2 Instituto Español de Oceanografía, Spain. 1
The Cape Verde Frontal Zone separates North and South Atlantic Central Waters in the eastern North Atlantic Subtropical Gyre. CTD-O2 and shipboard ADCP data from three hydrographic sections carried out in September 2003 are used to study the structure of the front. Results show the relation between spatial variations of water masses and currents, demonstrating the importance of advection in the distribution of water masses. Diapycnal diffusivities due to double diffusion and vertical shear instabilities are also estimated. Existence of competition between the two processes through the water column is shown. Depth-averaged diffusivities suggest that salt fingering dominates diapycnal mixing, except areas of purest South Atlantic Central Water. Here, double diffusion processes are weak and, consequently, shear of the flow is the main process. Results also show that strong mixing induced by vertical shear is associated with a large intrusion found near the front.
Poster: P1+P2 P19
Interannual variability of the connection between the equatorial undercurrent and the Peru-Chile Undercurrent during 1999–2004 based on a high-resolution numerical model (ROMS) I Montes1, C. Böning2, F. Colas3, J. Tam4 and W. Schneider1 Universidad de Concepción. Departamento de Oceanografía and Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental. Barrio Universitario s/n. Cabina 5. Casilla postal 160-C. Concepción, Chile. Email:
[email protected] 2 Leibniz Institute of Marine Sciences at Kiel University (IFM-GEOMAR), Germany. 3 Institute of Geophysics and Planetary Physics, University of California Los Angeles, USA. 4 Instituto del Mar del Peru, Peru. 1
As some studies point out, one of the most remarkable features of the Humboldt Current system (HCS) is its remote connection with the Equatorial Current System; it has been indicated that the Equatorial Undercurrent (EUC: one of the principal components of the Equatorial Current System) feeds the Peru– Chile Undercurrent (PCUC: one of the principal components of the Humboldt Current System) during mean meteorological and oceanographic conditions, which is important because water masses associated with the Peru–Chile Undercurrent are the main source for coastal upwelling waters off Peru and northern Chile. Based on this hypothesis and considering that these regions are strongly affected by the interannual variability of ENSO events, we are interested in the investigation of the interannual variability of the interaction between the Equatorial Undercurrent and the Peru-Chile Undercurrent. For that, we configured a high-resolution numerical model (ROMS, ~12km) for the area encompassed between 70ºW - 94ºW and 4ºN-22ºS focussing on the period 1999 to 2004. The model was forced by QuikSCAT wind stress data (1/2°, daily), the climatology COADS was used for the heat and fresh water fluxes and, SODA-POP data (1/2°, monthly) for the boundary conditions. For the validation, we compared the model Sea Level Anomaly (SLA) with SLA maps calculated from altimetry data and show that the principal patterns of SLA are reproduced by the model although some discrepancies exists which are discussed. Further, we implemented a Lagrangian tracking submodel to our regional model in order to scrutinize the equatorial/tropical/subtropical coupling in the eastern South Pacific. 120
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Poster: P1+P2 P20
Thermal impact of the coastal waves in the coastal African upwelling areas A-C. Peter and A. Lazar LOCEAN, 4 place Jussieu, Paris 75005, France. Email:
[email protected]
Although their strong social and economic consequences on surrounding countries, the coastal upwellings along the tropical African coasts are not completely understood. These upwellings are explained by local processes but also by remote ones from equator. In particular, the equatorial Kelvin waves, excited by the zonal wind stress in the western equatorial part of the basin, propagate eastaward and are reflected at the eastern boundaries where part of the energy is reflected into Rossby waves and in coastal waves. Lagged correlations between sea level anomalies at the coast-equator and along the north and south coasts show that 25% of the variance in the upwelling areas is explained by the signal propagated along the coasts from the equator by the waves. In this work, we are interested in the thermal impact of the coastal waves in the upwelling areas along the african coasts. Using the mixed layer heat budget, coastal waves contribution to the horizontal advection term can be evaluated and compared to the contribution of local forcing by wind stress which acts on vertical mixing, latent heat flux and local currents. These different contributions can be added, as in 1996 boreal spring, or cancelled each other, as in 1999-2000 boreal winter. When added, the waves can modulate the SST in order of 1°C.
Poster: P1+P2 P21
Distribution of volatile halogenated organic compounds in the Iberian Peninsula upwelling system S. Raimund1, P. Morin1, M. Vernet1, Y. Morel2, F. Jourdin2 and V. Garçon3 Station Biologique de Roscoff/ CNRS, Place Georges Teissier BP 74, Roscoff, 29680, France. Email:
[email protected] LEGOS/SHOM Toulouse, France. 3 CMO/ SHOM Toulouse/Brest, France. 1 2
Upwelling systems are characterised by high primary productivity and constitute significant sources and sinks of numerous compounds that can influence atmospheric chemistry. Among these compounds, the volatile halogenated organic compounds (VHOC) are known to influence atmospheric ozone chemistry. They have both anthropogenic and natural sources, and are globally emitted by chemical and biological processes in the ocean. Thus, salt water habitats constitute a major source of halogens in the atmosphere. Macroalgae and different phytoplanktonic species living there are known to produce different VHOC (e.g. CH2Br2, CHBr3, CH3Br, CH3Cl…). Formation conditions of these compounds by phytoplankton in different marine environments have not been largely investigated. Moreover the contribution of macroalgae and phytoplankton to the VHOC production are still a matter of debate. It is known that the role of macroalgae to the primary production in upwelling systems is low. For this reason upwelling ecosystems are interesting places to study the isolated contribution of phytoplankton to the global budged of atmospheric VHOCs. VHOC distributions were investigated in an upwelling area during a survey along the coast off Portugal which took place during summer 2007 (August 11th to September 14th) on the French research vessel Pourquoi pas?. Organized by the Service Hydrographique et Océanographique de la Marine (SHOM) the survey took place within the framework of the Modélisation océanique d’un théâtre d’opérations navales (MOUTON) program. VHOC concentrations were measured in surface water and air samples along transects parallel and perpendicular to the upwelling area to estimate the air-sea exchanges in and outside the upwelling. Day-night variations in VHOC concentrations were followed with a 30-hour sampling strategy at fixed points within and external the upwelling. Correlations and non correlations between VHOCs and chemical and biological features (nutrients, chlorophyll) obtained during these different spatio-temporal studies will be shown. Refinements of the existent GC-ECD methods of VHOC measurement will be also presented. 121
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Poster: P1+P2 P22
Spatio-temporal variability patterns, episodic events and coupling effects among remotely sensed sea surface temperature, chlorophyll concentration, dynamic topography and wind fields in the Canary upwelling system G. Rodríguez1, L. García-Weil1, A. González2, J.L. Vega1, D. Suarez1 and J. Coca2 1 2
Departamento de Física, Universidad de Las Palmas de Gran Canaria, 35017, Las Palmas, Spain. Email:
[email protected] Departamento de Biología, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain.
There is no doubt about the coupling between the atmosphere and the oceans, largely due to fluxes of momentum and heat through their common boundary, the sea surface. This tight link is especially relevant in eastern boundary oceanic systems, which have long been recognised as highly productive zones due to coastal upwelling and play a key role from the socioeconomic and ecological points of view due to significant volume of resources. Thus, the main eastern boundary upwelling systems (Peru-Chile, Canary, Benguela, and California) are characterised by important fisheries. Each one of these regions is characterised by a quite specific dynamic, with the wind playing a major role in the dynamics of physical, biogeochemical and ecological processes. Placed under the influence of alongshore blowing trade-winds, the offshore Ekman transport of surface waters induce upwelling of cold, nutrient rich deep waters nearshore, which triggers favourable conditions for the development of a rich and complex food chain. The upwelling intensity is modulated by the force and direction of the wind, by the topography of the coast and the continental shelf, and by the environing oceanic characteristics. Furthermore, an intense mesoscale activity develops along the coastal transition zone as a combination of upwelling fronts, offshore squirts and filaments, and eddies. These features are part of a highly non-linear dynamical system associated to the basic upwelling process and generate relevant cross-front water masses exchanges between the coastal and deep ocean zones. The Canary upwelling ecosystem includes the northwest African and the western Iberian coasts, and extends from 13ºN to 43ºN. The present study restricts to the central area, between 23-33ºN, where upwelling persist throughout the year with intensification and relaxation phases. In this region the Canary Current upwelling system is typical in terms of the above, but presents a considerable mesoscale activity enhancement due to the presence of the Canary archipelago. In general, the aim of the study is to go beyond the descriptive phase and to explicitly link the driving term of upwelling, the wind velocity, to the dynamic height (SSH), temperature (SST), and chlorophyll concentration (Chl-C) in the ocean surface, through statistical models. To reach this goal, various representative sub-areas within the studied region are chosen to examine the spatial variability of wind velocity, SST, Chl-C, SSH in the ocean surface. Sub-areas are distant enough to not give trivial results, but of sufficient closeness for making possible their interaction. The study is based on QuikSCAT satellite scatterometer wind speed and direction measurements (1999 – 2007), SSH data derived from the combination of TOPEX/POSEIDON, or Jason-1, and ERS-1/2, or Envisat, (1992- 2007), SST data from the NOAA AVHRR (1985 - 2007), and chlorophyll concentrations derived from SeaWiFS data (1997–2007). In brief, the present investigation aims: (1) to examine the structure and spatio-temporal behaviour of the wind velocity, wind stress, and wind stress curl in response to coastal topographic forcing of the marine airflow, as the main driving factor of the upwelling dynamics, as well as that of SSH, SST, and Chl-C, by considering geographical variations and temporal evolution at short and long terms, to model recurring and persistent patterns of fluctuation. For this, robust statistical techniques to test for cycles and long-term memory are used. (2) to identify and model coupling and interplay among patterns of physical and biological processes, including the possible existence of time lags, and quantify the relative importance of the couplings on different time scales. Special attention is focused on anomalous, or episodic, events which significantly depart from the prominent conditions (anomalous wind forcing periods, warming or cooling events, etc). These events, which are usually sudden, can have a great impact on biological processes and interrupt the observed marked seasonal cycle. Methods used to identify coupling phenomena between different processes are based on the cross-interaction concept for non-linear and non-stationary signals, useful both for examining short and long term time patterns and to detect the degree of coupling and the phase lag between processes. The application of these methods enables the objective analysis of the existence of recurring and persistent patterns, as well as couplings among the examined complex time series. Furthermore, results obtained 122
Eastern Boundary Upwelling Ecosystems Symposium by comparison with classical methodological approaches evidence clear advantages in the analysis of experimental data by using the proposed methods, especially for nonlinear relationships and weak interactions detection.
Poster: P1+P2 P23
Formation of a secondary upwelling front along the shelf break in simplified numerical models and in situ data V. Rossi1, Y. Morel2 and V. Garçon1 1 2
LEGOS/CNRS, 14 Avenue Edouard Belin, Toulouse, Midi-Pyrénées , 31400, France. Email:
[email protected] CMO/SHOM, Toulouse/Brest, France.
The eastern boundary regions of the ocean have many common characteristics related to their source of waters, the nature of the flow, the phenomena resulting from local atmospheric circulation, and the presence of boundaries imposed by the continental masses. The basic processes of upwelling formation are wellknown: an along-shore dominant wind (physical forcing) results in an offshore Ekman transport 90° to the right of the wind (northern hemisphere), in the surface mixed layer, compensated by a vertical transport of deep, cold and rich nutrient water at the coast. Under a southward wind stress, considering a coast meridionally oriented in the northern hemisphere, the resultant currents are the surface Ekman current directed to the west, a coastal jet flowing equatorward and a counter-current above the slope directed to the pole during most of the year. This cross shelf structure may be modulated by the local conditions including topographic features. In this work we address the question of the physical mechanism leading to the formation of secondary upwelling fronts. Indeed, during MOUTON 2007 several data were collected in the Iberian Peninsula upwelling system (IPUS), and among all these, an east/west section located at 41°N reveals a nice snapshot of two upwelling fronts clearly characterised by cold water tongues. We first analyse the in situ data focussing on the formation of these two upwelling fronts, the classical one located at the shore and the other one above the shelf break, associated with a special biological activity. A simplified numerical model is then built in order to reproduce and understand the physical mechanisms behind this observation. We use a simple 2 dimensional model, derived from MICOM (or Miami Isopycnic Coordinate Ocean Model), with two distinct layers. The model is able to reproduce these two fronts under some ‘pretty general’ circumstances. The mechanism is then analysed in terms of potential vorticity dynamics (onshore transport of high potential vorticity anomalies on the shelf).
Poster: P1+P2 P24
Multiscale analysis of satellite chlorophyll a data around two upwelling foci in Northern Chile J. Rutlant1, P. Paolini2 and V. Montecino1 1 2
Universidad de Chile, Blanco Encalada 2002, Santiago, 837-0449, Chile. Email:
[email protected] MAPSAT Ltd., Chile.
Satellite-derived chlorophyll a data (Csat) around two leading upwelling foci in Northern Chile were classified according to phases (cold-neutral-warm) of the annual and inter-annual (ENSO) cycles. These phases have been previously associated with thermo/nutricline depths: cold (shallow), warm (deep) and neutral (average), upon which quasi-weekly upwelling-favourable wind events result in different degrees of upwelling effectiveness (i.e. nutrient pumping into the euphotic zone). Data classified in this manner were first ranked into five environmental indices (EIs) according to all possible phase-combinations of the ENSO and annual cycles, from absolutely cold (0) to absolutely warm (4); and then merged into three equallyweighted environmental conditions (ECs): mostly cold, neutral and mostly warm. The selected upwelling foci were Point Angamos (~23°S) at the northern edge of the Mejillones Peninsula, and Point Lengua de Vaca (~30° 15’S), at the southern edge of a large embayment that extends up to Point Choros (~29° 15’S). Each focus is associated with an adjacent, north-facing bay lying in the so-called upwelling shadow: the Mejillones and Tongoy Bays, respectively. In addition, the nearby Antofagasta (~23° 30’S) and Cruz Grande (~29° 20’S) south-facing bays, unprotected from the upwelling-favourable winds, 123
Eastern Boundary Upwelling Ecosystems Symposium have been included for comparison. As in previous work, mean Csat values tended to peak around neutral ECs at both upwelling foci and over the south-facing bays, whereas north-facing bays showed increasing Csat concentrations from cold to warm ECs. While nutrient input into north- facing bays from adjacent upwelling foci during active upwelling has been widely documented, it is hypothesised here that also during active upwelling strong inshore winds within these bays spin-up a cyclonic windstress curl fostering local nutrient re-suspension during relaxation. This mechanism secures nutrient supply and high biomass growth even during warm ECs, despite an overall deeper nutricline at the corresponding upwelling focus. Strong turbulent mixing and offshore transport during active upwelling upwind of south-facing bays would prevent nutrient input into these bays. It is suggested that nutrient supply to these bays would mostly occur in connection with wind reversals during relaxations, explaining the peak in Csat values during neutral ECs.
Poster: P1+P2 P25
Seasonal variability of fCO2 and O2 in the Angola-Benguela region J. Santana-Casiano, M. González-Dávila and I. Ucha Faculty of Marine Science, Universidad de Las Palmas de Gran Canaria, Campus de Tafira, Las Palmas de Gran Canaria, Las Palmas, 35017, Spain. Email:
[email protected]
The variability of fCO2 and O2 has been studied in the region between 5ºS and 30ºS in the south-east Atlantic region since July 2005. High fCO2 variability has been observed in the surface seawater due to the effect of upwelling and derived mesoscale structures like filaments. The surface temperature change sinusoidally according with the seasonal solar cycle in five-degree latitudinal sectors for the south Atlantic Ocean. A difference of about 4-5º is observed between the austral summer and winter for each sector. The highest values for the fCO2 seasonal variability are found in March for all the sectors. The latitudinal sectors 10-15ºS and 25-30ºS present a minimum in September while, in the other sectors, minimum values appear in July. The 5-10ºS presents the highest values for each period (418 μatm) and the sector 25-30ºS the lowest (370 μatm). This is related with the latitudinal gradient observed for the temperature. The 5-10ºS sector shows ∆fCO2 >0 all year around, acting the system as a source of CO2. The 10-15ºS sector presents ∆fCO2 >0 in the austral summer, working the system as a source of CO2 and ∆fCO2 <0 in winter, being a sink of CO2. The 25-30ºS sector has ∆fCO2 <0 from May to December acting principally as a sink of CO2. Fluxes are computed for each sector using climatology wind speeds. The highest values for O2 seasonal variability are found in October-November and the lowest values in April-May according with the seasonal cycle of temperature. The 25-30ºS sector presents the highest values of O2 in each period due it is the sector with the lowest temperature.
Poster: P1+P2 P26
The impact of sea-surface temperature on surface winds along Senegalese coasts B. Sow1,2, P. Marchesiello3 and C. Roy4 Université de Ziguinchor, BP 523, Ziguinchor, Senegal. Email:
[email protected] LPAO-SF/ESP/UCAD, Senegal. 3 IRD Noumea Center, France. 4 Centre IRD de Bretagne Plouzané, France. 1 2
The aim of our study is to show the impact of sea-surface temperature (SST) on surface winds along Senegalese coasts. We realised a first experiment with the Weather Research and Forecasting model (WRF) completely forced by the NCEP reanalysis including SST. In a second experiment, the large scale NCEP SST was replaced with ROMS SST at finer resolution (15 km). The outputs of these experiments were compared with satellite measurements; QuikSCAT winds show that WRF simulations are close to measurements when the mesoscale SST (ROMS) is used as forcing. It seems that increase in SST leads to increase in surface coastal winds. WRF wind speed with large scale SST forcing (NCEP) is stronger than WRF wind speed with mesoscale SST forcing (ROMS) in coastal area where SST ROMS is cooler than NCEP SST. In other studies, satellite observations of surface winds and SST reveal that the ocean 124
Eastern Boundary Upwelling Ecosystems Symposium exerts a strong influence on boundary layer winds, but the details of the boundary layer processes involved in this ocean-atmosphere interaction are not completely understood. Our idea is that increase in SST leads to a higher MABL depth and a mixing between weaker surface winds and stronger winds at the top of the MABL. This mixing accelerates the surface winds over warm waters, but the thermodynamical and physical arguments need to be developed to better understand of the phenomena. These results are in good agreement with those found by Chelton et al (2007) in California coast. It seems also necessary to use a finer resolution for the SST forcing to capture small-scale winds.
Poster: P1+P2 P27
Three-dimensional circulation in Montery Bay using the General Curvilinear Ocean Model C. Torres1,2, J. Castillo2, J. Mueller3, C. Trees3 and M. Stramzka3 Institute for Oceanological Research, Universidad Autónoma de Baja California, Km 107 Carr. Tijuana-Ensenada, Ensenada, Baja California, 22800, Mexico. Email:
[email protected] 2 Modelling Ecosystems Dynamics Group, San Diego State University, USA. 1
Monterey Bay (MB) is the largest bay of the West Coast of the United States. It is characterised by a complex coastline and regions of steep bathymetry. Local upwelling events and strong land/sea breeze influence circulation patterns in this area. Topographical characteristics as well as atmospheric and oceanographic conditions and processes make the MB region ideal to exploit the capabilities of a 3D curvilinear ocean model such as the General Curvilinear Ocean Model, GCOM. GCOM is based on the non-hydrostatic, nonlinear primitive equations for momentum and density in the f-plane. It is capable of handling the complex combination of rotation and abrupt bathymetry. It has been used successfully to model flow circulation and density evolution in a variety of places with different coastline and shape basins such as The Gulf of Mexico, The Gulf of California and The Bahia de Todos Santos in Mexico. For the Monterey Bay case, density and velocity fields are presented for various flow conditions.
Poster: P1+P2 P28
Climatology and circulation of the Azores-Canary region by Data-Interpolation Variational Analysis C. Troupin1, F. Machín2, M. Ouberdous1, P. Sangrà3 and J-M. Beckers1 University of Liège, Building B5a, Allée du 6 Août, 17, Liège 4000, Belgium. Email:
[email protected] Institut de Ciències del Mar, CMIMA-CSIC, Spain. 3 Oceanografia Física, Universidad de Las Palmas de Gran Canaria, Spain. 1 2
The Azores-Canary region, located off NW Africa, is characterised by a strong mesoscale variability induced by the presence of the Canary archipelago in the passage of the Canary Current, the outflow of Mediterranean water and upwelling filaments generated near the capes (Ghir, Jubi, Blanco) of the NW Africa coast. The available climatologies (World Ocean Atlas 2001; World Ocean Atlas 2005; HydroBase) do not permit a good representation of those mesoscale phenomena, since their resolution is sensitively larger than the typical length scale of the processes (Rossby deformation Radius). Although numerous cruises were carried out in the region (CANIGO, RODA, etc.), few were focused on the compilation of the data available in the region. With these arguments in mind, we used the software DIVA (Data-Interpolation Variational Analysis) based on the Variational Inverse Method (Brasseur et al., 1996, Deep-Sea Research) on the data collected from major data sets in order to reproduce monthly, seasonal and annual climatologies of temperature and salinity at various depths. The avantages of DIVA is the consideration of the real topography and the advection during the interpolation process, as well as the error field computed with the analysis. Data were extracted from the World Ocean Database (2005), Hydrobase 2, Coriolis, MedAtlas 2 and CANIGO campaign. Quality control and duplicate detection were performed in order to construct a large database. Individual profiles were interpolated at standard pressure levels with the weighted parabolic interpolation method. Reconstructed temperature and salinity fields are then used to compute geostrophic velocity field and obtain a high-resolution description of the circulation in the region of interest. Our results are compared with other existing climatologies and with satellite images for the surface temperature fields. 125
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Poster: P1+P2 P29
Vorticity balance in the northwestern African upwelling C. Troupin1, E. Mason2 and P. Sangrà2 1 2
University of Liège, Building B5a, Allée du 6 Août, 17, Liège 4000, Belgium. Email:
[email protected] Oceanografía Física, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
Process studies of the drainage of the Canary Current by the northwestern African upwelling (NWAU) have shown that, in order to conserve potential vorticity, the southward flow along the upwelling system should be accompanied by a negative (anticyclonic) relative vorticity, which is provided by the upwelling jet circulation. We use a high-resolution primitive-equation model (ROMS) to study the vorticity balance along the NWAU. The model is configured within a domain encompassing the entire northeast Atlantic subtropical gyre, at resolutions as high as 1.5 km. Mean seasonal forcing, applied at the surface and open lateral boundaries, is sufficient to generate mesoscale variability that is consistent with observations of the NWAU. The upwelling jet introduces negative relative vorticity, while upwelling filaments are characterised by positive relative vorticity with a submesoscale cyclonic eddy at their tips. Our hypothesis of upwellingfilament generation is related to the injection of positive relative vorticity. As the flow gains positive vorticity, it becomes unable to continue southward and detaches from the coast. One source of positive vorticity is wind shear at the capes along the northwest African coast. It has been shown that the distribution of positive wind curl along the NWAU coincides with the main area of filament generation (Bakun and Nelson, 1991, Journal of Physical Oceanography). Other sources of vorticity are bottom torque and topography. Depth increase toward the ocean interior could also inject positive vorticity, leading to the generation of submesoscale anticyclonic eddies at the filament tips. Different numerical experiments with increasing degree of complexity will be presented in order to test these vorticity sources and their role in the generation of upwelling filaments in the NWAU.
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P3
Coastal - open ocean fluxes and processes
5 June, 15:15 (P3 KNS)
Physical processes of shelf-open ocean exchange and their Influence on upwelling ecosystems J. Barth College of Oceanic and Atmospheric Sciences, Oregon State University, 104 COAS Admin Bldg, Corvallis, OR, 97331-5503, USA. Email:
[email protected]
One of the distinguishing characteristics of eastern boundary current upwelling systems is the efficient exchange of water and the material it contains between the shelf and adjacent deep ocean. This communication is two way, including the supply of nutrients and, coincidently, low-oxygen water to the shelf from the deep ocean as well as the export of chlorophyll and larvae to the deep ocean after their production on the shelf. This exchange occurs via a variety of two- and three-dimensional processes, each of which varies on time scales from hours (internal tidal bores) to decades (decadal variability in upwelling source water characteristics). The nature of the exchange varies from the inner shelf to the continental slope as the coastal and topographic constraints lessen offshore. Recent multi-disciplinary studies using new platforms, including towed and autonomous vehicles, land-based coastal radar and microstructure, and advanced measurement techniques, for example for carbon species, dissolved oxygen and trace metals, have advanced our understanding of the influence of physical exchange processes on upwelling ecosystem dynamics. While relatively two-dimensional, wind-driven upwelling and cross-shelf Ekman transport form the foundation of shelf-open ocean exchange, the details of this exchange – interior water column versus boundary layer, diminished exchange in the inner-shelf, variable sourcewater chemistry – and its modulation by climate variability and change are of intense current research. As an example, the degree of open-shelf hypoxia in the world’s upwelling ecosystems is influenced by both physical and biological processes, varies between regions and is sensitive to climate variability. Strongly three-dimensional and time-dependent processes like coastal jet instability and separation at bathymetric features and coastal promontories can dominate exchange processes. This flow-topography interaction plays a critical role in the ecology of eastern boundary currents, for example by setting scales and regions of larval connectivity. Even with recent progress, year-round observations of shelf-open ocean exchange are still lacking, especially at higher latitudes where seasonal variations and storms present observational challenges. The prospects for improving continuous, year-round observations of eastern boundary upwelling ecosystems using ocean observing systems are reviewed.
5 June, 15:45 (P3 OP1)
An upwelling filament west of Cape Finisterre in August 2005 M. Ruiz Villarreal1, R. Sánchez2, C. González Pola3, A. Bode1, A. Calvo-Díaz3, C. Rodríguez2 and A. Lavín2 IEO, Centro Oceanográfico A Coruña, Muelle de Animas s/n. 15001 A Coruña, Galicia. Spain. Email:
[email protected] IEO, Centro Oceanográfico de Santander, Spain. 3 IEO, Centro Oceanográfico de Gijón, Spain. 1 2
Upwelling filaments are cold-water tongues with their source in the upwelling zone that may reach some 50 km of width and up to 300 km of length. When they occur, their activity has been acknowledged as a major contributor to cross-shelf exchange. AVHRR imagery shows that Cape Finisterre is a preferred site for filament formation, but no subsurface observations of its properties have been performed. To date in situ observations of filaments in the NE Atlantic are limited to the Cape St. Vincent, NW Iberia off Vigo and a number of events in the Canary region. In this contribution we report observations of the Finisterre filament during the August 2005 occupation of the Spanish Deep Standard Section at 43ºN. Measurements include CTDO2, nutrients and currents from vessel-mounted ADCP and LADCP. Additionally, measurements of chlorophyll a (total and fractionated) and picoplankton community were performed. The analysis is complemented with satellite imagery (AVHRR, QuikSCAT, AVISO altimetry and SeaWiFS). SST on 17 August 2005 together with VM-ADCP velocity vectors averaged over the top 50 m. The filament was embedded in a complex upwelling region featuring a number of mesoscale eddies and offshore filaments 127
Eastern Boundary Upwelling Ecosystems Symposium rooted at Cape Finisterre. The section, performed from 20-22 August 2005 transected the filament along its longitudinal axis. The filament thermohaline signature was that of the upwelling region, with T<17 ºC contrasting with 20ºC offshore, and salinity<35.7 versus values greater than 35.9 offshore. Seaward ADCP velocities occurred over the top 100 m of the water column and were greater than 0.2 m/s, although a detailed analysis revealed a finer scale spatio-temporal variability associated with meandering of the filament. Chlorophyll values within the filament were greater than outside, particularly for cells > 2 μm diameter. In contrast the presence of Prochlorococcus along the upwelling area and its filament projection was dramatically reduced, which revealed its impact on picoplanktonic communities. In summary, the filament appeared much more consistent than simply a surface structure, consisted in offshore squirts associated with the eddy field. However, these preliminary results suggest that the overall volume transport, although much larger than the purely wind-driven one, did not imply huge cross-shelf water exchanges, which did not impede considerable export of pelagic biota.
5 June, 16:00 (P3 OP2)
Analysis of an upwelling event off central Portugal: links between physical processes and phytoplankton patterns J. Dubert1, P. Oliveira2, Á. Peliz1 and R. Nolasco1 1 2
Campus de Santiago, Departamento de Física, Universidade de Aveiro, Aveiro, 3810-193, Portugal. Email:
[email protected] L-IPIMAR, INRB, Portugal.
Numerical modelling techniques and satellite-derived sea surface temperature (SST) and chlorophyll-a (Chl a) concentration maps are used, to study the coastal upwelling dynamics and advection patterns during a summer upwelling event off central Portugal. The upwelling event, consist of a strong wind (max 12 m/s) during 5 days, followed by a period of relaxation observed in July 2005. The ocean simulations were performed using the Regional Ocean Modelling System (ROMS) with embedded nesting capabilities, in order to attain the target resolution of 900m, which allowed the proper resolution of the sub-mesoscale processes associated to the upwelling phenomena. The forcing used consists in the realistic output of the WRF (Weather Research and Forecasting Model) model at 15km resolution, including tides, river inflow, and realistic conditions on stratification. The model solutions reproduce the main patterns of spatial and temporal SST variability, and the expected circulation features: the strong coastal jets, the development of filaments and jet separation at Capes Carvoeiro and Roca, frontal-scale instabilities and the onset of coastal counter currents along the inshore zone during the relaxation period. A Lagrangian sub model is used to determine the impact of the shelf circulation on water displacements, allowing insight on potential origins and destinations of the upwelled water, and relates them to the evolving SST and Chl a patterns. An asymmetric Chl a concentration relative to SST pattern is observed during high winds regime (> 5m/s), with low values of Chl a along the axis of the cold filament and high values along the southern filament boundary, associated to low advection conditions and shallow mixed layer depths. Several aspects of this asymmetry, its temporal evolution and associated physical processes are discussed.
5 June, 16:15 (P3 OP3)
Fish larvae from the Canaries-Africa coastal transition zone: a review J.M. Rodríguez1, M. Moyano2 and S. Hernández-León2 1 2
IEO, Centro Oceanográfico de Gijón, Avda. Príncipe de Asturias 70Bis, 33213 Gijón, Asturias, Spain. Email:
[email protected] Universidad de Las Palmas de Gran Canaria, Spain.
This contribution reviews relevant information on the ichthyoplankton of the Canaries-African Coastal Transition Zone (Canaries-ACTZ). This CTZ is characterised by intense mesoscale oceanographic activity. The Canary Archipelago interrupts the main flow of the Canary Current and Trade Winds introducing large mesoscale variability, in the form of island warm wakes and cyclonic and aniycyclonic eddies, downstream of the islands. Besides, upwelling filaments stretch towards the archipelago from the African coastal upwelling, transporting biogenic material, including fish larvae and interacting with island eddies, to exchange water properties and biogenic material. These mesoscale features influence the composition, abundance and distribution of the larval fish assemblage of the region. In summer, the transport of African neritic larvae by upwelling and upwelling filaments is responsible for the dominance of the larval fish assemblage by 128
Eastern Boundary Upwelling Ecosystems Symposium African neritic species and for the relatively high average larval fish abundance found in the region. Also, larval abundance is higher on the northern side of upwelling filaments and it tends to increase from the core towards the periphery in cyclonic eddies and from the periphery to the core in anticyclonic eddies. Filaments originated in the region of cape Juby are entrained around a quasi-permanent cyclonic eddy, trapped between Gran Canaria and the African coast, forming a system through which most of the African neritic larvae may return to the African shelf. However, some larvae reach the eastern islands of the Canary archipelago and they may be spread all over the neritic region of the archipelago by eddies shed from the islands contributing to the recruitment of local fisheries. Island eddies and the Canary Current drag island neritic larvae and transport them into the oceanic region. Nevertheless, eddies and warm wakes also seem to work as retention mechanisms and nursery areas for the Canary Islands neritic fish populations. Also in summer, the distribution of the larval fish assemblage of the Canaries-ACTZ is vertically stratified, but independent of the thermocline position. In addition, larval fish species seem to carry out little or no daily vertical migration. This may have implications for the horizontal distribution of fish larvae in the presence of vertical shear, as they would not take advantage of currents flowing in opposite direction, at different depths to maintain their positions at sea.
5 June, 16:30 (P3 OP4)
Particle fluxes and particle transport from the shelf to the open ocean off Cape Blanc, Mauretania: results from observational and modelling studies G. Fischer1, G. Karakaş2, R. Schlitzer2, N. Nowald3 and G. Wefer3 Geosciences Department, University of Bremen, Klagenfurter Strasse, University of Bremen, Bremen, 28359, Germany, Email:
[email protected] 2 Alfred Wegener Institute for Polar and Marine Research, Germany. 3 Center for Marine Environmental Sciences (MARUM), Bremen University, Germany. 1
Particle flux measurements combined with in situ analysis of particle characteristics (e.g. settling rates) and modelling studies have been performed for a few years off Cape Blanc, Mauretania, to assess the transport of particles in the water column and material export from the shelf to the open ocean. Meso- and bathypelagic particle fluxes offshore Cape Blanc, Mauretania, appear to be influenced by production and export of particles from the coastal region. At the eutrophic site CBi (80 nm offshore), mass fluxes in winterspring reached more than 1000 mg m-2 d-1. Further offshore at the mesotrophic site CB (200 nm offshore), mass fluxes decreased by a factor of two. There, the flux records of the bathypelagic CB traps point to an additional particle source from the shelf region. By assuming particle settling velocities of 30 m per day, we were able to model particle blooms extending from the shelf along the slope to the open ocean, consistent with our observations. However, to reproduce organic carbon fluxes monitored by the deep mesotrophic CB trap, a biogeochemical model with seasonal changing settling velocities of particles (75 and 150 m per day) has to be applied. These findings point to several classes of particles having different settling rates. In general, particle settling rates in the carbonate- and dust-dominated production system off NW Africa appear to be relatively high compared to the production systems dominated by biogenic opal. This might explain the relatively high organic carbon fluxes in the Canary Current system.
5 June, 16:45 (P3 OP5)
Copepod distribution in the coastal transition zone off Concepción, Chile C. Morales1, L. Torreblanca1, P. Hidalgo1, S.E. Hormazabal2, S. Nuñez3, G. Yuras2, R. Escribano1 and A. Sepúlveda3 COPAS, Universidad de Concepción, Casilla 44 Dichato, Dichato, BioBio, VII Chile. Email:
[email protected] DGEO, Universidad de Concepción, Chile. 3 INPESCA, Chile. Proyectos FONDECYT Nº 1070504 y FIP Nº 2006-05 1 2
The region off central Chile (30-38ºS) in the Humboldt Current system (HCS) is one of high eddy kinetic energy, the coastal transition zone (CTZ) extending 600-800 km offshore. Satellite information reveals mesoscale eddies (~200 km diameter) which remain as coherent spatial structures for several months 129
Eastern Boundary Upwelling Ecosystems Symposium and propagate predominantly offshore. Also, cold, chlorophyll a rich filaments are recurrent and extend out to ~400 km from the coast. Information about the effects of these mesoscale features upon the pelagic community and biological production in this CTZ is scarce compared with what is known about the coastal upwelling system. The distribution of mesoscale features and their potential association with the composition and abundance of copepods in the CTZ surface layer (0-100 m) were investigated. Samples were obtained during a survey of the egg and larvae distribution of jack mackerel (Trachurus murphyi), an important fisheries resource. 220 stations were sampled (0-100 m) over a 12 day period in the area 35-38°S, 7482.5ºW, using a Bongo 220 um net. For comparison, samples (11) were taken within the same period in the coastal band, using a Tucker trawl 300 um net (0-200 m). Satellite data (sea-surface temperature, chlorophyll-a, altimetry) for the period of the cruises were also analysed. Copepods were the numerically dominant component of the meta-mesozooplankton community (78% of the total) in the CTZ surface layer. Small copepods, both calanoids (Clausocalanus-ParacalanusNannocalanus) and cyclopoids (Corycaeus-Oncaea-Oithona), were the most abundant. Among the large copepods, Calanus chilensis, a typical component of the coastal upwelling area, were widely distributed in the CTZ. Total copepod abundances were highest (>50 m-3) 400-500 nm offshore; maximum abundances in the nearshore stations were just one order of magnitude larger. The patchy distribution of copepods in the CTZ region appears to be associated with cyclonic-anticyclonic eddy activity. Most of the copepods in the oceanic region were not dominant components in coastal upwelling waters (<60 nm from the shore). Altogether, these results suggest that biological production in the oceanic sector of the CTZ in this part of the HCS is relatively high and might account for the successful development of the early stages of jack mackerel far away from the coastal zone.
5 June, 17:30 (P3 OP6)
Mesoscale eddy activity in the southern Benguela upwelling system from altimetry and model data A. Rubio1, B. Blanke1, S. Speich2 and N. Grima1 Laboratoire de Physique des Océans, UMR 6523 CNRS/IFREMER/IRD/UBO, 6, Avenue le Gorgeu CS93837, Brest, 29238, France. Email:
[email protected] 2 Laboratoire de Physique des Océans (LPO)/Université of Brittany, France. 1
This study falls within the scope of the InterUp project that aims at comparing by numerical modelling the property transfers between the open ocean and the coastal ocean in the major eastern boundary upwelling systems. Its first objective is the characterisation of the eddy activity in the southern Benguela upwelling system from absolute sea level deduced from remote-sensing measurements, using a wavelet-based technique for identification of coherent structures. Its second objective is the quantification of the crossshore exchanges actually achieved by these coherent structures. Weekly maps of sea level anomalies, gridded at 1/3° resolution, are obtained from the CLS database. Numerical simulations are obtained from the ROMS (IRD-UCLA version) regional model applied to the ocean region around South Africa with a resolution of 1/10° and forced by daily QuikSCAT-derived winds. We use the WATERS wavelet-based utility for identification of mesoscale eddies in fields of relative vorticity derived from either model surface velocities or satellite altimetry. We also use the ARIANE Lagrangian diagnostic tool to study the origins and the 3D evolution of some southern Benguela eddies identified in the model. We present statistics about eddy count, size, type and location, for a period of interest shared by model and satellite data, along the continental slope of the upwelling system. We characterise the seasonal and interanual eddy activity and we draw a comparison between mesoscale variability calculated by the regional model and ground truth accounted by satellite altimetry. The agreement between model and observations is fair and validates the modelling approach. Then the full volume of some southern Benguela eddies identified in the model is explored using forward and backward trajectories in order to investigate fates and origins of structures that are essential to ecosystem dynamics and equilibrium. Water mass modifications and interaction with bathymetry are especially investigated, mostly in terms of mass transfers between the coastal area and the open sea. 130
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 17:45 (P3 OP7)
The Benguela: a laboratory for comparative studies of eastern boundary current systems J. Veitch1, P. Penven2 and F. Shillington1 1 2
Department of Oceanography, University of Cape Town, Rondebosch, Cape, 7701, South Africa. Email:
[email protected] IRD, Laboratoire de Physique des Oceans (LPO), UMR 6523 (CNRS, Ifremer, IRD, UBO), France.
The Benguela system is one of the four major eastern boundary current (EBC) systems of the worlds oceans. It is unique among EBC systems in that, not only its equatorward, but also its poleward boundary is marked by a warm water regime. The termination of the western boundary Agulhas Current defines the southern limit of the Benguela Current system (BCS) and is commensurate with a highly energetic regime of turbulent mixing, associated with the path of anti-cyclonic Agulhas rings and locally-formed cyclonic eddies. The Regional Ocean Modelling System (ROMS), forced with climatological QuikSCAT winds, is used in this study to improve the understanding of the equilibrium dynamics of the BCS. The BCS can be divided into northern and southern regimes, based on distinct dynamic as well as topographical differences. Topographically, the division between the northern and southern regimes coincides with an abrupt narrowing of the continental shelf at ~28°S. The dynamic manifestation of the divide is associated with an upwellingfavourable wind stress maximum, a deep-reaching cyclonic feature, an alongshore offshore transport maximum and a stratification discontinuity on the shelf (i.e. more stratified in the south). In terms of heat exchange, at 28°S is a large negative mean offshore heat flux, which is compensated for by a large positive eddy heat flux. A modelling experiment in which the coastline and continental shelf have been straightened suggests that the wind is a primary forcing mechanism for this divide. The distinct northern and southern areas of the Benguela provide a good platform for a comparative study of upwelling regimes within one system and one model simulation. Characteristic of the northern Benguela system is a deep poleward current that is most intense between ~10-400 m and tends to follow the orientation of the shelf-edge. This poleward current advects water of tropical Atlantic origin into the northern Benguela system. A topographical control exists in the southern Benguela system such that the position of the upwelling front and the path of the Benguela Current closely follow the orientation of the shelf-edge. The path of the Benguela Current and its role as a vehicle for Agulhas rings produces a region of high eddy kinetic energies (EKE), of the order of several hundred cm2.s-2, off the shelf-edge in the southern Benguela juxtaposed by low EKEs on the shelf, of the order of 10-50 cm2.s-2.
5 June, 18:00 (P3 OP8)
Across-shelf advection of carbon and coastal zooplankton species in upwelling filaments of the northern California Current J. Keister1, W. Peterson2 and S. Pierce3 University of Washington, 104 COAS Admin Bldg. Corvallis, Oregon, 97330, USA. Email:
[email protected] NWFSC, NOAA, USA. 3 College of Oceanic and Atmospheric Sciences, Oregon State University, USA. 1 2
In eastern boundary current (EBC) upwelling ecosystems, mesoscale circulation features such as eddies and upwelling filaments play a prominent role in the transfer of water and the associated plankton from the productive near shore to the oligotrophic deep sea. As part of the U.S. Global Ocean Ecosystems Dynamics (GLOBEC) Northeast Pacific Program, we are studying the relationship between mesoscale circulation, zooplankton distributions, and the across-shelf transport of coastal taxa and biomass in the California Current System. From 1998-2003, we conducted summer surveys of the hydrography and zooplankton in upwelling regions off Oregon and northern California, USA. Circulation patterns differed among cruises. During several cruises, patterns of zooplankton distributions along transects which crossed mesoscale features indicated the advective nature of the features. In summer 2000, we used CTD casts, zooplankton net tows, and Acoustic Doppler Current Profiler (ADCP) velocities to characterise a filament of the coastal upwelling jet which extended seaward of a coastal promontory (Cape Blanco, 42.8°N). The filament resulted in the displacement of coastal zooplankton to >100 km off the continental shelf. We used velocities and standing stocks of zooplankton to estimate that 0.5 Sv (1x106 m3) of water, containing an average zooplankton biomass of ~20 mg carbon/m3, was transported seaward across the 2000 m isobath in the upper 100 m of the filament each second. That flux equated to offshore transport of >900 metric tons of carbon each day, and 4-5x104 tons over the 6-8 week lifetime of the circulation feature. Although 131
Eastern Boundary Upwelling Ecosystems Symposium the flux represented a small portion (<3%) of the shelf zooplankton biomass, the transport resulted in an offshore “hot-spot” in which biomass was 3-4X higher than in the surrounding ocean. Distributions of early life history stages of euphausiids indicated that retention of coastal populations may be strongly affected by the offshore advection. Abundance of marine mammals was elevated along the offshore fronts. Thus, mesoscale circulation features play an ecologically important role in the transport of carbon to the deep sea, the retention and loss of taxa from the continental shelf, and creation of offshore structure where upper trophic level organisms may thrive.
5 June, 18:15 (P3 OP9)
Intermediate Nepheloid Layers in the central California Coastal Zone E. Rienecker, J. Ryan and B. Sackmann Monterey Bay Aquarium Research Institute , 7700 Sandholdt Rd, Moss Landing, Ca, 95039, USA. Email:
[email protected]
Intermediate Nepheloid Layers (INLs) are frequently encountered in routine Autonomous Underwater Vehicle (AUV) surveys of Monterey Bay, California and adjacent waters. INLs are of importance due to their ability to transport nutrients and sediments both laterally, from the shelf into the Coastal Transition Zone (CTZ), and vertically, from the benthic boundary layer into the mixed layer. High resolution AUV surveys have mapped INLs over horizontal scales ranging from 5 to 30 km and vertical scales ranging from 10 to 200 meters. By integrating synoptic measurements from autonomous platforms with remote sensing we are probing the relationships between INLs and the physical processes that force their lateral and vertical transport: specifically upwelling, eddies, and frontal dynamics. Of particular interest is how INLs’ transport particles from the bottom nepheloid layer into the mixed layer, and how these particles influence plankton ecology. Our presentation will examine INL scales, variability, composition, development and fate and their potential influences on phytoplankton ecology in this ocean margin environment.
5 June, 18:30 (P3 OP10)
On the role of eddies for the transport of organic matter from eastern boundary upwelling regions to the open ocean N. Gruber1, T. Nagai2, Z. Lachkar1, D. Loher1, H. Frenzel3, J. C. McWilliams3 and G-K. Plattner1 Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich 8092, Switzerland. Email:nicolas.
[email protected] 2 Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Japan. 3 Institute of Geophysics and Planetary Physics, UCLA, USA. 1
Observations and recent high-resolution numerical studies of eastern boundary current systems have suggested that meso- and submeso-scale features, such as filaments, jets, and eddies are a primary determinant of biogeochemical balances. However, the role of these abundant features for the transport of biogeochemical properties from the productive nearshore environment typical of eastern boundary current systems into the relatively unproductive offshore regions has not been quantified well so far. Here, we investigate and compare the fluxes of carbon and associated nutrient elements in two eastern boundary current systems, i.e. the California Current System (CalCS) and the Canary Current System (CanCS), using high-resolution (5 km) coupled physical-biogeochemical numerical models with special emphasis on the quantification of the offshore transport and the mechanisms determining it. The model we employ is the Regional Ocean Modelling System (ROMS), which has been augmented with a NutrientPhytoplankton-Zooplankton-Detritus (NPZD) model and a full description of carbon biogeochemistry. Reynolds decomposition analyses of the model simulated lateral fluxes in the CalCS reveal that eddies and other mesoscale processes rather than Ekman-driven flow dominate the offshore transport of organic matter there. Analyses for the CanCS are underway, but due to the substantially lower eddy-kinetic energy of this system, we suspect that the eddy contribution to the offshore transport is smaller as well. But whether the total transport is smaller remains to be uncovered. 132
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 18:45 (P3 OP11)
Mapping and variability of cross-shore mass transfers in the four major easternboundary upwelling systems B. Blanke1, A. Bentamy2, X. Capet3, N. Chang4, F. Colas5, B. Dewitte6, V. Echevin7, N. Grima1, E. Machu9, P. Marchesiello9, P. Penven10, C. Roy10, S. Speich11, J. Veitch4 and P. Verley12 Laboratoire de Physique des Océans (LPO), UFR Sciences et Techniques, 6 avenue Le Gorgeu – C.S. 93837, 29238 Brest Cedex 3, France. Email:
[email protected] 2 Laboratoire d'Océanographie Spatiale - Center for Satellite Exploitation and Research, Ifremer, France. 3 Instituto Oceanográfico, Universidade de São Paulo, Brazil. 4 Department of Oceanography, University of Cape Town, South Africa. 5 Center for Earth Systems Research & Department of Atmospheric and Oceanic Sciences & IGPP, University of California, USA. 6 LEGOS, IRD, Toulouse, France. 7 LOCEAN, France. 8 Laboratoire de Physique des Océans (LPO), IRD, France. 9 LEGOS, IRD, Nouméa, France. 10 Laboratoire de Physique des Océans (LPO), IRD, France. 11 Laboratoire de Physique des Océans (LPO)/Université of Brittany, France. 12 Eco-UP/IRD, France. 1
This study is part of the InterUp project that is dedicated to the comparison by numerical modelling of the transfers between the coastal and open ocean in the four major eastern boundary upwelling systems. InterUp is a French INSU-funded project with additional financing from Ifremer. It is a partnership between scientists at LPO, EcoUp, Legos, Locean, Los-Cersat, UCLA and UCT. Our study aims at characterising inshore and offshore fluxes in regional ocean simulations run with equivalent horizontal resolution (roughly 1/12°) and duration (≈10-year-long simulations), with monthly climatological or daily wind stress, in the four upwelling systems. Common diagnostics are used to identify and quantify cross-shore fluxes, to map the transferred fluxes and to investigate their time variability. The main collaborators of the project provide the model outputs for the Benguela, Canary, Humboldt and California upwelling systems, and the Lagrangian processing is done mostly with the Ariane offline toolkit (http://www.univ-brest.fr/lpo/ariane). The intercomparison of the results aims at a better understanding of the similarities and contrasts between the various systems, and will provide clues for a better identification of the key processes at work, in relation with biogeochemistry and ecosystemic studies.
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P3 Posters Poster: P3 P1
Impact of Coastal Kelvin waves on the nearshore productivity in the Humboldt Current system A. Albert1, V. Echevin1, M. Lévy1, O. Aumont2 and J. Ledesma3 LOCEAN, UPMC, Bureau 427, 4 Place Jussieu, Boite 100, Paris, 75005, France. Email:
[email protected] Laboratoire de Physique des Océans, Université Bretagne Ouest, France. 3 Instituto del Mar del Peru, Peru. 1 2
The Humboldt Current system is the most productive upwelling system in the world ocean. Due to its proximity to the tropics, it is highly sensitive to the intense intraseasonnal to interannual fluctuations originating from the Equatorial Pacific, which propagate poleward along the Peruvian coasts in the form of coastal Kelvin waves. These waves act to displace upward or downward the thermocline and the nutricline, generating a modification of the nutrient input into the euphotic zone and modifying the nearshore mesoscale activity. The impact of this process on the primary productivity of the upwelling system, the structure of the ecosystem, the offshore and downward export of organic mater is evaluated for the different characteristics of the waves during the period 2000/2006 using SeaWiFS sea color data, DUACS altimetric observations and numerical simulations from a regional coupled dynamical/ biological model forced by realistic dynamical forcing and WOA2005 climatological biogeochemical conditions. The impact of the coastal waves on the biological activity is contrasted with regards to the seasonality of the upwelling system.
Poster: P3 P2
Variability in the water column respiration across the NW Africa-Canary Current Coastal Transition Zone I.J. Alonso-González, J. Arístegui, J.C. Vilas, M. Montero and M. Espino Facultad de Ciencias del Mar, Campus Universitario de Tafira, Universidad de Las Palmas de Gran Canaria, Casillas del Angel nº 42ª, Puerto del Rosario 35017, Las Palmas de Gran Canaria, Spain. Email:
[email protected]
We have studied the temporal and regional variability in the water-column (0-1000 m) respiration during two oceanographic cruises carried out in the Northwest Africa -Canary Current Coastal Transition Zone (CTZ), during September 2002 and June 2003. We measured the respiratory activity of the electron transport system (ETS) in the epipelagic (0-200 m) and mesopelagic (200-1000 m) zone, along two sections extending from the costal upwelling to the open ocean at 21 N and 26 N. The epipelagic and mesopelagic waters exhibited contrasting zonal patterns of distribution. At 21N, the epipelagic ETS was higher on the coastal stations, associated with the Cape Blanc filament, decreasing towards the ocean, while at 26 N the surface open-ocean waters presented higher ETS than near the African shelf. The ETS in the mesopelagic zone didn’t display a clear zonal or regional trend, like in the epipelagic. However, the mesopelagic waters showed a significant temporal variability, being the ETS 26% higher in autumn (202 mmol O2 m-2 d-1) than in late spring (150 mmol O2 m-2 d-1). Since primary production was lower in autumn, we hypothesise that the mesopelagic respiration was mainly controlled by the seasonal fluctuations in the organic matter supply from the continental margin, rather than from vertical sinking of particles from the euphotic zone. This hypothesis is supported by the low export fluxes (1-10 mmol C m-2 d-1) recorded with drifting sediment traps during the same study. Moreover, peaks in ETS activity were observed through the mesopelagic zone, suggesting hot-spots of remineralization of suspended organic carbon, which might be laterally transported. Overall, the average integrated ETS activity in the mesopelagic zone (176 mmol O2 m-2 d-1) was high with respect to other oceanic regions, and comparable in magnitude to the epipelagic ETS (189 mmol O2 m-2 d-1). This gives evidence of the importance of the dark waters of this CTZ as a sink of carbon in the northeast Atlantic Ocean. 134
Eastern Boundary Upwelling Ecosystems Symposium
Poster:: P3 P3
Fast food: the transport of particulate organic matter over an upwelling event on the west coast of southern Africa A. Biccard, G. Branch and M. Pfaff University of Cape Town, Private bag X3, Rondebosch, Cape Town, 7701, South Africa. Email:
[email protected]
Particulate organic matter, the primary food source of coastal consumers, is delivered to the intertidal zone by certain oceanographic processes. Such processes are predicted to have a significant effect on the quality and quantity of POM supplied to nearshore intertidal and subtidal zones. Differences in the concentrations of phytoplankton (Chlorophyll a) and kelp-derived particulate organic matter were investigated at different distances offshore and at different depths for a month during the upwelling season, between an exposed headland (Cape Columbine) and a sheltered bay (Elandsbaai) in the southern Benguela. Physical data, in agreement with previous studies, showed that Cape Columbine is situated within an upwelling center and Elandsbaai within an upwelling shadow. Three distinct oceanographic conditions, upwelling, relaxation and downwelling, were discernable from wind, current and temperature data at each site. Upwelling was most prevalent at Cape Columbine in contrast to relaxation at Elandsbaai. Significant differences (P < 0.00001) in chlorophyll a concentration, quantities of organic carbon and % kelp-derived carbon were found between the two sites. In addition, significant differences (P < 0.0001) in chlorophyll a concentration, quantities of organic carbon and % kelp-derived carbon were found between the different oceanographic conditions: upwelling, relaxation and downwelling. A significant interaction (P < 0.00001) for % kelp-derived carbon was found between site and oceanographic conditions. Tests within study sites revealed significantly higher chlorophyll a concentrations in the upper layer, as expected. Furthermore, chlorophyll a concentrations showed a significant decrease with distance offshore at Elandsbaai. Percentage contribution of kelp-derived carbon (max = 36%) to POM was lower than predicted and surprisingly lower than values reported in previous works (77%). No stratification of kelp-derived matter or organic carbon was observed in the water column at both sites. It is likely that sampling stations were too shallow i.e. water column was well mixed as a results of nearshore turbulence. In terms of food supply to coastal consumers, upwelling episodes at Cape Columbine resulted in significantly high import of kelp matter into the nearshore water column. In contrast, phytoplankton, constituted the primary food source for both sites during relaxation and downwelling episodes. It is clear that different oceanographic conditions between an exposed headland and a sheltered bay have profound implications regarding the transport, composition and supply of POM, as a source of food to coastal communities.
Poster: P3 P4
Modelling the structure and circulation of the Agulhas Bank, South Africa N. Chang1, P. Penven2 and F. Shillington1 Department of Oceanography, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7700, South Africa. Email:
[email protected] 2 IRD, Centre IRD de Bretagne, France. 1
The Agulhas Bank is the continental shelf south of Africa, triangular in shape it spans approximately 800 km along the coast and at its apex, 250 km offshore. Its oceanic complexity lies in its position between two diverse regimes: the strong western boundary current, the Agulhas Current, and the eastern boundary regime of the Benguela upwelling system. The Agulhas Bank is the spawning and nursery ground to many fish species. In addition, the doming of isotherms on the East Agulhas Bank (EAB) known as the Cool Ridge may play a role in chokka squid development. It is therefore important to understand the structure and circulation that comprise this dynamic region. The Regional Ocean Modelling System (ROMS) was used to model the Agulhas Bank region. A one-way nested model was used to obtain a finer resolution of 8 km. This model was nested within the ROMS configuration SAfE (South African Experiment). SAfE is a 25 km resolution model which resolves the greater southern African oceanic region, in particular, the Agulhas Current and its source regions, and the Benguela Upwelling System. The model was able to reproduce the seasonal mean circulation and structure of the Agulhas Bank as well as the Cool Ridge. Mean circulation over the outer Agulhas Bank shelf appeared to be influenced by the Agulhas Current. The Agulhas Current also contributed to the formation of the Cool Ridge in the model. Seasonal mean currents in the shallower coastal regions were wind-driven. The Central Agulhas Bank, formed a transitional area between the above two regions and displayed weak westerly mean flow. 135
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P3 P5
Oceanic versus coastal contribution of N2O in the upwelling zone off Central Chile M. Cornejo1,2, L. Farías2 and M. Gallegos2 Programa de Doctorado en Oceanografía, Departamento de Oceanografía, Universidad de Concepción, Cabina7 Barrio Universitario s/n Casilla 160C, Concepción, Chile. Email:
[email protected] 2 Departamento de Oceanografía & Centro de Investigación Oceanográfica COPAS, Universidad de Concepción, Cabina 7 – PROFC, Casilla 160-C, Concepción, Chile. 1
The coastal zone off Central Chile is an important source of N2O to the atmosphere, with fluxes as high as 195 µmol m-2 d-1. High surface N2O concentrations are mainly due to the upwelling events that are present most of the year (~60%) and are particularly intense during the austral spring summer time. Such input fluctuates over the year with the highest positive N2O flux, from the ocean to the atmosphere, during the austral summer and the lowest and some negative N2O fluxes, from the atmosphere to the ocean, during the austral winter time. This work evaluates the role, as a source of N2O to the atmosphere, of an area off Central Chile constrained between 32ºS and 37.5ºS and 71ºW and 78.6ºW. The surface N2O concentration fluctuated between 4.8 and 134 nM with a decreasing gradient from the coast to the open. The upwelling of low O2 and high nutrients waters in this area is considered the major mechanism that supplies N2O to the atmosphere. Because of this the air-sea N2O fluxes research is generally restricted to a narrow band close to the coast. The high primary production driving by the upwelling develop the subsurface anoxic condition enhancing the N2O production by microbial processes increasing the N2O that will be brought to the surface by the upwelling, making a feedback. However, when we observed the oceanic zone of the studied area the upwelled waters were mixed, and new waters from the south were present. These waters were observed all the year in the oceanic zone and in some coastal regions during the winter, which have low temperatures and low N2O concentrations, which made them able to capture N2O from the atmosphere. Finally, an interpolation of all the data existing in the zone of N2O concentrations and air-sea fluxes since 2000 to date will be presented, taking into account the coastal and oceanic zones, and comparing them in both austral summer and austral winter time. The low N2O water content of these waters may balance the high N2O source observed in the coastal band. The results could change our vision of the region merely as a source of N2O.
Poster: P3 P6
Impact of an upwelling filament off southwest Iberian Peninsula upon the nutrient and chlorophyll a distributions A. Cravo, S. Cardeira, M. Madureira and P. Relvas Univ. Algarve - CIMA, FCMA, Campus de Gambelas, Faro, Algarve, 8005-139, Portugal. Email:
[email protected]
The Cape São Vicente is an upwelling center under favourable wind conditions and is the origin of one of the major and recurrent cold filaments observed along the southwest Iberian Peninsula. The main objective of this work was to understand the dynamics of the filament and determine its implications on the chemical and biological fields. Such multidisciplinary description through in situ sampling of a filament feature along the southwest Iberian Peninsula has never been achieved before and allowed the estimation of the excess of offshore mass transport. The survey was conducted by the end of October 2004 (late in the upwelling season), under relaxed winds, i.e. in a decaying stage. It was carried out just after a period of relatively strong and persistent upwelling favourable northerlies, as confirmed through the almost real-time guidance by satellite imagery. A total of 42 CTD stations were sampled along with water collection for the analysis of nutrients and chlorophyll a at several levels (from surface to a maximum depth of 400 m). Simultaneously, continuous onboard wind records and flow field data from the vessel mounted ADCP were acquired. At surface the nutrients concentration was lower than expected, due to its effective consumption by phytoplankton. The strongest horizontal and vertical gradients were found between 50 and 75 m depth. The maximum value of chlorophyll a (3.6 μg/L) was found at the nearshore stations at 20 m depth and represents a high concentration for this time of the year. Although the offshore decrease of chlorophyll a concentration, relatively high values (≥0.3 µg/L) can be found at 60-80 km from the coast along the filament axis. An estimate of the total amount of chlorophyll present in the filament was 66 tonnes. Estimated values of fluxes and transport of nutrients and chlorophyll a revealed that filament structures such this one found, represents an efficient way of exchange with the open ocean, even at this time of the year, having a key impact on the control of primary production. 136
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P3 P7
Coastal upwelling variability in Central America (Panama) L. D'Croz and A. O'Dea Smithsonian Tropical Research Institute, Balboa, Ancon, Panama, Apartado 0843-03092, Panama. Email:
[email protected]
Strong wind-jets from the Caribbean and the Gulf of Mexico cross Central America through topographic depressions in the cordillera during the boreal winter, pushing Pacific coastal waters offshore, lowering sea levels, and causing strong coastal upwelling. Where high mountains impede the winds, this phenomenon does not occur. The Panamanian Pacific shelf is an excellent example of this variability. The coast is divided in two large areas, the Gulf of Panama (upwelling) and the Gulf of Chiriquí (non-upwelling). To investigate nutrient and chlorophyll dynamics between the two gulfs we sampled the water column in cross-shelf transects during upwelling and non-upwelling seasons in each region, measuring temperature, salinity, dissolved nutrients, and chlorophyll a concentrations. In both Gulfs during non upwelling conditions, surface level nutrients are poor and the chlorophyll maximum occurs at around 30 m where the thermocline intersects the photic zone. When wind strength increased, strong upwelling was observed in the Gulf of Panama. The thermocline migrated upwards and surface waters became nutrient enriched and chlorophyll a level rise. In the Gulf of Chiriquí, wind strength was weaker and surface waters did not become enriched with nutrients and surface chlorophyll a levels remained low. However, we did observe a shallowing of the thermocline in the Gulf of Chiriquí, but unlike in the Gulf of Panama wind mixing was not strong enough to result in sea-surface cooling and nutrient enrichment. We do not rule out that the shallowing of the thermocline in the Gulf of Chiriquí is likely to increase the chances that pockets of deep water occasionally migrate into surface waters leading to restricted and ephemeral upwelling-like conditions. By including data on rainfall in both regions we conclude that the position of the thermocline is the most important factor in determining nutrient levels in the euphotic zone in both regions.
Poster: P3 P8
Reproduction seasonality in Octopus vulgaris: two versus one breeding peaks under different upwelling regimes J. Pereira, A. Moreno, S. Lourenço and M. de Fátima Borges Instituto de Investigação das Pescas e do Mar, Av. Brasília, s/n, Lisboa, 1400-038 Lisboa, Portugal. Email:
[email protected]
Octopus vulgaris is a bottom-dwelling species with pelagic paralarvae. The species is widely distributed over mainland shelf waters, as well as in distant oceanic islands and seamounts of the eastern Atlantic. The paralarval phase can represent up to 25% of the longevity of the species and is highly sensitive to environmental conditions, including water mass characteristics and food availability. Data on maturation and other biological parameters are used to define breeding seasons for octopus landed by artisanal fisheries and collected in research surveys in two oceanographically distinct Portuguese coastal areas: the northwest (western Iberia upwelling ecosystem) and the south (Gulf of Cadiz ecosystem). The effects of interanually different temperatures and upwelling intensities on the variability in reproduction parameters are analysed for the period between 1997 and 2007. Year round spawning was observed in fisheries and survey data on both areas of Portuguese waters. However, on the northwest coast there are two peaks, one in March and another in July, while on the south coast, there is a single summer peak. The northwestern and southern areas of the Portuguese coast benefit from upwelling conditions, yet different parts constitute different oceanographic regimes in terms of upwelling intensity, retention processes and concomitant effects on mean water temperature. The spawning strategies of octopus on the Portuguese coast and other upwelling systems show that the species is capable of adjusting its population dynamics in terms of spatial and temporal optimisation of enrichment and retention processes that benefit the planktonic paralarvae. Wherever possible by the special characteristics of oceanographic regimes, the species can display two rather than one spawning peak. 137
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P3 P9
Carbon fluxes due to diel vertical migrant zooplankton in the transition zone between the North African upwelling and oceanic waters S. Putzeys, C. Almeida, P. Bécognée and S. Hernández-León Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, 35017 Tafira Baja, Las Palmas de Gran Canaria. Canary Islands, Spain. Email:
[email protected]
The vertical distribution (0-900m) of zooplankton biomass and indices of grazing (gut fluorescence, GF) and metabolism (electron transfer system activity, ETS) were studied along two sections at 26ºN and 21ºN in the transition zone between the highly productive area of the NW African upwelling, the Canary Islands waters and the oceanic waters of the North Atlantic subtropical gyre. Two dense layers of organisms were observed during the day, one above 200 m and the other layer located at about 500 m, coincident with the deep scattering layer (DSL). Migrant biomass values calculated from day and night biomass profiles ranged between 240.8 mmolC m-2 in the upwelled waters, to 35.7 mmolC m-2 in Canary Island waters and 11.9 mmolC m-2 in the subtropical waters. It is well know that the diel vertical migration plays a determining role in the downward flux of particulate and dissolved matter. The respiratory flux mediated by migrant biomass showed a gradient from productive zones with a high respiratory flux (0.59-60.23 mmolC m-2 d-1) to the oligotrophic zone with low respiratory flux (0.12-1.52 mmolC m-2 d-1). The total active flux was estimated summing up the gut and respiratory fluxes and a similar gradient was observed which ranged from 4 to 53% of the POC flux.
Poster: P3 P10
Hidrodinámica y simulación numérica de la circulación superficial y subsuperficial de las corrientes marinas asociado al sistema de afloramiento costero (11ºS) J. Quispe1, C. Torres3, O. Morón2, N. Dominguez1, J. Tenorio1 and L. Vásquez1 IMARPE-Dirección de Investigaciones Oceanográficas, Unidad de Investigaciones en Oceanografía Física. Esq. Gamarra y Gral Valle s/n, Chuchito Callao, Peru. Email:
[email protected] 2 Dirección de Investigaciones Oceanográficas, Unidad de Investigaciones en Oceanografía Química, Instituto del Mar del Peru, Peru. 1
3
Computational Science Research Center, San Diego State University, USA.
Se presentan los resultados del estudio sobre la hidrodinámica del sistema de circulación superficial y subsuperficial asociado con el sistema de afloramiento costero entre los 11ºS y 15ºS de latitud sur, con énfasis en los cambios estacionales de la variabilidad oceanográfica, en base a registros de información de cruceros oceanográficos realizados por el IMARPE, para reproducir los fenómenos oceanográficos complejos que se presentan en la interacción del transporte de flujo y la topografía. El sistema de corrientes en el área de estudio está compuesto por la Corriente Costera Peruana (CCP) y la Corriente Oceánica Peruana (COP), provenientes del sur que transportan aguas de origen subantártica. Dentro de estas dos se presenta la Contracorriente Peruana que fluye en sentido contrario a las anteriores; es decir, de Norte a Sur, que en algunos escenarios llega hasta los 15o S con velocidades que van disminuyendo paulatinamente, presenta mayores velocidades entre los 100 y 200 m de profundidad llegando su acción hasta debajo de los 500 m. Con ecuaciones pronosticas, tales como densidad y el uso de las ecuaciones no lineares del ímpetu, varios procesos relevantes a una variedad de flujos estratificados no lineales se pueden modelar correctamente en la alta resolución por GCOM (General Curvilinear Ocean Model). Realmente, GCOM esta diseñado para estudiar la circulación en diferentes geometrías complejas. Los procesos hidrodinámicos en el océano abierto generalmente involucran la interacción tridimensional entre corrientes, topografía submarina y líneas de costa con geometrías complejas. La topografía submarina local y la línea de costa modifican las corrientes en la vecindad de estructuras marinas. Otros factores como las mareas, vientos y gradientes de densidad también influyen en el transporte de masa de constituyentes químicos y biológicos. GCOM (General Curvilinear Ocean Model) es un modelo tridimensional en coordenadas curvilíneas con aplicaciones a fluidos geofísicos desarrollado por el Dr. Torres en conjunto con el grupo del Profesor Larrazábal. La versión actual de GCOM resuelve las ecuaciones de movimiento sobre una malla ajustada al fondo marino y a la línea de costa, siendo capáz de manejar la combinación de rotación y topografía de fondo y línea de costa complejas. Mediante ecuaciones pronósticos de densidad (o temperatura) y el uso de las ecuaciones alinéales de movimiento, diversos procesos pertenecientes a un espectro relevante de fluidos estratificados alinéales pueden modelarse apropiadamente por GCOM. Fenómenos oceanográficos 138
Eastern Boundary Upwelling Ecosystems Symposium complejos que surgen de la interacción topografía-fluido, como jets sobre montañas marinas, han logrado ser reproducidos por GCOM. Una descripción más detallada de GCOM puede encontrarse en Torres y Castillo (2003). El modelo a utilizar es capáz de resolver con exactitud la dinámica de las diferentes capas límite y su interacción con las características topográficas de la región de estudio. El uso de mallas curvilíneas incrementa la eficiencia y eficacia del modelo para investigar regiones con formas irregulares y complejas con el propósito de cubrir los requerimientos de alta resolución en zonas específicas que sean de interés. Todas estas características son la base del modelo GCOM para identificar y caracterizar la respuesta de la dinámica de corrientes frente a los procesos físicos e hidrodinámicos que alteran la dinámica local para determinar la influencia en el sistema de afloramiento costero .
Poster: P3 P11
MOUTON 2007: a field survey of the Iberian Peninsula Upwelling System V. Rossi1, Y. Morel2, J. Tassel2, F. Jourdin2, P. Morin3 and V. Garçon1 LEGOS/CNRS, 14 Avenue Edouard Belin, Toulouse, Midi-Pyrénées, 31400, France. Email:
[email protected] CMO/SHOM Toulouse/Brest, France. 3 Station Biologique de Roscoff/CNRS, France. 1 2
The Iberian Peninsula upwellling system (IPUS) belongs to one of the four major eastern boundary upwelling ecosystems, the Canary upwelling system. These coastal areas, located on the eastern part of the oceanic basins, constitute the largest contribution to the world ocean productivity thus playing a key biological and socio-economical role. These areas are particularly characterised, among other features, by a strong alongshore advection, physical forcing by local and large scale winds, seaward extension beyond the continental shelf of the boundary current and an active biological activity via filaments formation. This MOUTON survey conducted by SHOM (Service Hydrographique et Océanographique de la Marine, the french Navy’s oceanographic institution), LEGOS/CNRS laboratory and Marine Biological Station from Roscoff, took place on board the R/V “Pourquoi Pas?”. Its goal was to thoroughly study the upwelling area and its associated ecosystem from both the physical and biogeochemical perspectives. These in situ oceanographic data and those from former surveys (MOUTON 2004/2005) are being used as validation products for a regional ocean model of the IPUS and as a support to highlight particular processes occurring in the area. The survey took place during summer 2007 (August 11th – September 14th), which is usually an active period of upwelling formation. It focussed on the northern part, north of 39°N and was composed of several transects (East/West, and North/South) with deployment of different instrumentations (CTD equipped with PAR, oxygen sensors, transmissometer and fluorimeter, ADCP, ARGO floats, Seasoar, zooplankton net...). We will present here the main water masses flowing in the area along with a selection of a few ADCP data transects to detail the circulation patterns. We will then analyse the different phases of the upwelling development, in particular, from the upwelling formation to the organic material offshore export. The high temporal frequency variability is studied using 30 hours continuous sampling at three different fixed points. The large scale North/South gradient in terms of physical and biogeochemical characteristics was investigated with different sampling strategies whereas we analysed the East/West gradient following a filament extension offshore.
Poster: P3 P12
Physical description of an upwelling filament off southwest Iberian Peninsula R. Sánchez2, P. Relvas1, A. Martinho3 and P. Miller4 CIMA/Universidade do Algarve, Faro, Univ. Algarve, FCMA – Portugal. Email:
[email protected] IEO, Centro Oceanográfico de Santander, Promontorio San Martín s/n, 39004, Santander-Cantabria, Spain. 3 Instituto Hidrográfico, Portugal. 4 Plymouth Marine Laboratory, Remote Sensing Group, Plymouth, United Kingdom. 1 2
In late October 2004 an upwelling filament that develops off Cape São Vicente (southwest Iberia) was studied through remote sensing and in situ observations. A total of 42 CTD casts and continuous ADCP acquisition were performed, guided by satellite sea surface temperature imagery received onboard in almost real-time. The campaign took place under relaxed winds, after a period of relatively strong and persistent upwelling favourable northerlies. In consequence the filament was sampled in a decaying stage. 139
Eastern Boundary Upwelling Ecosystems Symposium Yet, this filament adds an effective mechanism for cross-shelf exchange close to Cape São Vicente. It transported 0.9 Sv of coastal water offshore, the equivalent to the Ekman transport of a 8.5 m/s wind over the entire western Iberian coast (800 km). The Ekman transport accompanying the filament at the time of the cruise was about 0.07 Sv (8% of the observed transport). To the south of the offshore jet, a shallow return flow of 0.4 Sv was observed. The filament appeared to be associated with the baroclinic upwelling jet flowing equatorward off the west Iberian coast, destabilized and meandering close to the Cape São Vicente. The filament was structurally asymmetric. Relative geostrophic vorticity was anticyclonic to the north of the filament and more strongly cyclonic to the south, as a result of the meanders and existing eddies, whereas the filament was comprised of a sequence of cold, sub-mesoscale (about 30 km diameter) cyclones. Meanders of the jet caused vertical velocities of about 15 m/day, which had an impact upon the patchy distribution of chlorophyll-a. A comparative analysis with other filaments along the Canary (including Iberia) and California EBUS revealed that, although it is also associated with a meandering jet, the smooth surface-trapped (top 100 m) horizontal density gradients and weak dynamical structure made this filament more similar to filaments sampled off northern Iberia rather than to observations in the eastern Pacific region. The causes of the discrepancies appeared to be related to enhanced baroclinicity in the Pacific.
Poster: P3 P13
Ocean Color and SST distribution derived from satellite and airborne data in the Ria of Vigo J. Torres Palenzuela1, L. Vilas1, J. Herrero2 and E. D. Barton3 Applied Physic Dep. Fac. Ciencias del Mar. Lagoas-Marcosende, Dep. Física Aplicada, VIGO, Pontevedra, 36310, Spain. Email:
[email protected] 2 Signal Theory and Communications, University of Vigo, Spain. 3 Departamento de Oceanografía, Instituto Investigaciones Marinas, Spain. 1
The Ria de Vigo is a coastal inlet strongly influenced by the processes of coastal upwelling and downwelling on the adjacent continental shelf. During the period from May to September, the introduction of nutrientrich waters far into the Ria by upwelling circulation makes it highly productive and allows the economically important cultivation of mussels. Downwelling in autumn and winter can introduce damaging 'red tides' that force temporary but expensive closure of the culture. An airborne survey was completed on September 27 and 28, 2006 by the NERC Do-228 aircraft of the EUFAR fleet aimed at providing a synoptic sample of the surface distributions of temperature and ocean colour over this area. Aircraft was equipped with two multispectral sensors operating in the visible and nearinfrared regions of the spectrum: CASI (14 bands) and ATM (11 bands). The ATM sensor is also provided with a thermal infrared band. At the same time, a boat campaign was carried out in order to collect in situ data on suspended matter, dissolved carbon and turbidity, as well as water-leaving radiance measurements using a portable spectroradiometer and sea surface temperature data from a temperature and depth logger. Satellite ocean colour data from the MERIS and MODIS sensors were also available. In this work a combined approach is proposed to study the ocean colour spatial distribution along the Ria using radiometry measures from the aforementioned methods: satellite, aircraft and spectroradiometer. Field data were used to remove the atmospheric effects in satellite and aircraft images, which in their turn provided a highly detailed mapping of the nearinstantaneous situation in the study area. In this way, maps of the main water quality parameters estimated from classical band ratios and neural nets trained using in situ data were obtained. On the other hand, sea surface temperature maps were derived from the ATM thermal band and field data using a neural net. Results show that satellite and airborne data are a powerful tool to improve the understanding of the dynamic of the Ría and its effects on the productivity and biology.
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nutrient cycles and the OMZ, and processes P4+P6 Biogeochemistry, in the sediments and at the sediment-water interface 5 June, 15:15 (P1+P2 KNS1)
Biogeochemical cycling in eastern boundary upwelling systems: large signals from small, temporally variable volumes L. Codispoti Horn Point Laboratory, University of Maryland Centre for Environmental. Science, P.O. Box 775, Cambridge, MD , 21613-0775, USA. Email:
[email protected]
Eastern boundary upwelling systems (EBUS) differ in some important details such as the strength of their oxygen minimum zones (OMZs), nutrient ratios in upwelling source waters, and maximum chlorophyll accumulations, but they share several important characteristics. With respect to biogeochemical cycling all of these systems represent sites of amplified nutrient supply, cycling and retention. Amplifiers, rheostats, feed-backs and switches in the biogeochemical system transform the initial modest increases in nutrient supply to orders of magnitude greater fisheries yields per unit volume compared with the “average ocean”, and to greatly enhanced sites for sedimentary deposition of organic carbon. The occurrence of extremely low oxygen concentrations in some EBUS make them globally significant sites of fixed-nitrogen removal and nitrous oxide production. In such cases only small re-distributions of carbon flux and dissolved oxygen can turn the denitrification “switch” and significantly alter the nitrous oxide “rheostat”. The “Phosphorite Giant” formations associated with some EBUS, further highlight the importance of these relatively small systems to global biogeochemical processes. As we transition from the Holocene to the Anthropocene, we may find that biogeochemical conditions in EBUS are hyper-sensitive to change because of the relatively small volumes involved, the presence of waters on the verge of hypoxia and suboxia adjacent to some EBUS, and increasing anthropogenic pressure on coastal systems.
5 June, 15:45 (P4+P6 KNS2)
Natural hypoxia variability in upwelling systems: sediment fluxes or physical ventilation? P. Monteiro1,2, A. van der Plas3, J-L. Mélice4 and W.R. Joubert2 Department of Oceanography, University of Cape Town, Rondebosch, South Africa. CSIR, PO Box 320, Stellenbosch, South Africa. Email:
[email protected] 3 Ministry of Fisheries and Marine Resources, Namibia. 4 IRD/ Department of Oceanography, University of Cape Town, South Africa. 1 2
Significant differences in the characteristics of natural hypoxia variability among the eastern boundary upwelling systems raise questions about the extent to which sediment biogeochemical fluxes alone can explain the observations. The variability of natural coastal hypoxia is divided between two main hypotheses: the biogeochemical oxygen demand linked to locally-driven sediment fluxes or to changes in the fluxes of oxygen by physical advection. The precise role of each mechanism has remained elusive. We examined the dynamical characteristics of coupled physical – biogeochemical processes that modulate seasonal and interannual coastal hypoxia in the Benguela upwelling system in the south-east Atlantic. The results highlighted the role of advection to explain much of the seasonal – interannual variability. The results showed that the variability was insensitive to changes in the carbon export fluxes but strongly dependent on the advected oxygen fluxes. The dynamics of the interaction of equatorial and sub-tropical boundary conditions (ocean – shelf exchange) and seasonally phased shelf advection were the key forcing functions that explained hypoxia variability in seasonal – decadal time scales. Crucially, without a remote trigger the local forcing would not develop anoxic conditions because the physical flux of oxygen would be too high. This work provides some useful clues to understanding the differences in the hypoxia characteristics in otherwise comparably productive upwelling systems. Understanding the vulnerability of upwelling systems to climate change requires that both local sediment biogeochemical fluxes and remote physical forcing process scales be addressed. 141
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 16:15 (P4+P6 OP1)
Seasonal changes of net ecosystem metabolism in the coastal upwelling system of the Ría De Vigo (NW Spain) C.Castro, F. Alonso-Pérez, B. Arbones and F. Figueiras Instituto de Investigaciones Marinas- C.S.I.C., Eduardo Cabello 6, Vigo, Pontevedra, 36208, Spain. Email:
[email protected]
Between April 2004 and January 2005, a station in the main channel of Ría de Vigo was visited 16 times to investigate the coupling between primary production, vertical export fluxes and benthic fluxes. Short time-scale samplings on a biweekly frequency were carried out for the four typical seasons of this upwelling system. During these cruises, measurements of in situ gross primary production (GPP) and dark community respiration (DCR) with in situ 24h oxygen incubations were carried out. Besides, the vertical fluxes of biogenic material from the euphotic zone and the benthic fluxes of oxygen and nutrients were measured by means of 24h-sediment trap deployments and 8h benthic chamber incubations respectively. Plankton community production presented a seasonal variability in terms of GPP and Net Community Production (NCP) with maxima during the summer upwelling (462 and 406 mmol O2 m-2 d-1 for GPP and NCP respectively) and minima during winter (52 and 22 mmol O2 m-2 d-1 for GPP and NCP respectively). Integrated respiration rates for the euphotic zone ranged from 10 to 195 mmol O2 m-2 d-1 with average value of 66 ±53 mmol O2 m-2 d-1, with maximum values during spring and summer and minimum values during winter. High (low) pelagic respiration occurred with maximum (minimum) values of primary production which points to a close relationship between these two metabolic processes. In contrast, the vertical fluxes of organic carbon were relatively similar for the four study periods, with an annual organic carbon flux average of 1.3 ±0.5 gC m-2 d-1. However, the benthic fluxes of oxygen and nutrients also presented seasonal variability with maximum fluxes during the autumn season (45 mmol m-2 d-1, 2.6 mmol m-2 d-1 and 6.9 mmol m-2 d-1 for oxygen, inorganic nitrogen and silicate respectively). Our result show that between 0.26 and 0.54 gC m-2 d-1 were remineralized in the benthos. Based on these benthic and pelagic fluxes and taking into account the primary production and respiration measurements, we have built up a 1D budget for the Ría de Vigo for the four study periods. These budgets show that (1) the NCP constitute between the 17-71% of the GPP; (2) between 29 – 81% of the GPP is respired in the photic zone; and (3) carbon oxidation at the sediment-water interface represented between 20 -44% of the settling organic carbon. Our results indicate that the water column metabolic balance inside the Ría de Vigo was autotrophic all year around. When we include the benthic respiration, the system as whole was autotrophic during the spring and summer periods and slightly heterotrophic for the autumn and winter periods.
5 June, 16:30 (P4+P6 OP2)
Living dangerously: implications of hydrogen sulphide for marine life along the Namibian coast B. Currie1, K. Peard2, V. Brüchert3, K-C. Emeis4, A.C. Utne Palm6, R. Endler5, A.G.V. Salvanes6 and R. Bahlo5 Ministry of Fisheries and Marine Resources, NatMIRC, P.O. Box 912, Swakopmund, Namibia. Email:
[email protected] Ministry of Fisheries and Marine Resources, Lüderitz Research Station, Namibia. 3 Max-Planck Institute for Marine Microbiology, Germany. 4 Institut für Biogeochemie und Meereschemie, University of Hamburg, Germany. 5 Institut für Ostseeforschung, Germany. 6 Department of Biology, University of Bergen, Norway. 1 2
Hypoxia, anoxia and free hydrogen sulphide in the water column are characteristic of the inner shelf coastal upwelling system off central Namibia. Biogeochemical monitoring of the diatomaceous sediments along the central coast over a three-year period, coupled with acoustic studies and ROV video coverage, indicated a major role played by the seafloor in the generation and control of H2S into the water column. We determined the sedimentary processes resulting in the generation and dispersal of hydrogen sulphide, and its effect on some of the locally important fishes and invertebrates. Marked interannual variability with no obvious seasonal trends was apparent in hydrogen sulphide and methane contents of sediments even over the three-year period. Large sulphur bacteria Thiomargarita namibiensis and Beggiatoa spp. form dense mats over extensive areas of mud and oxidize hydrogen sulphide at the sediment-water interface thereby regulating its flux to the overlying water. During episodic events however, hydrogen sulphide 142
Eastern Boundary Upwelling Ecosystems Symposium pervades the entire water column, followed by anoxia and severe hypoxia. Under experimental conditions, the survival of juvenile horse mackerel Trachurus trachurus capensis was limited to less than two hours in water containing <0.7ml.l-1 dissolved oxygen. If hydrogen sulphide was also present the survival time was reduced to less than 30 minutes. In contrast, pelagic bearded gobies Sufflogobius bibarbatus survived exposure to extended periods of anoxia and water containing hydrogen sulphide. These gobies are found abundantly on the muddy seafloor where they evidently possess both physiological and behavioural strategies to tolerate hydrogen sulphide and anoxia, accounting for the success of this species in Namibian waters and its importance as a key diet species for predatory fish, seabirds and marine mammals.
5 June, 16:45 (P4+P6 OP3)
Nitrogen gas supersaturation due to denitrification in waters underlying the euphotic zones of eastern boundary upwelling systems A. Devol and B. Chang University of Washington, Box 355351, University of Washington, Seattle, WA, 98195, USA. Email:
[email protected]
The high productivity of eastern boundary upwelling systems often results in low oxygen conditions in the sub-euphotic zone waters immediately below. In some areas, e.g. Peru upwelling system and off the west coast of Mexico, oxygen concentrations in the intermediate waters are reduced to the point that denitrification becomes the dominant respiratory pathway. These eastern boundary oxygen deficient zones account for about half the global marine denitrification. Here we present measurements of the amount of excess N2 in the denitrification zones of the Peru and Mexican eastern boundary upwelling zones as well as from the denitrifying zone in the northern Arabian Sea. These three areas contain virtually all the pelagic-denitrifying waters of the oceans. Measured nitrogen gas concentrations were normalized to argon to eliminate variations due to physical changes in the water mass. Any nitrogen gas in excess of the background nitrogen gas concentration was interpreted to be from denitrification. All three areas showed a maximum in nitrogen excess coincident with the zone of vanishingly low oxygen concentration. We also used nitrate-phosphate stoichiometry to determine the amount of nitrate that had been removed from the water column in the denitrification zone, i.e. the nitrate deficit. In both the Mexican upwelling system and Arabian Sea, the amount of excess nitrogen exceeded the nitrate deficit by order of 50%, while in the Peru upwelling zone the excess nitrogen and the deficit were in balance. The most likely explanation for the higher nitrogen excesses than deficits in the Mexican and Arabian systems is remineralization of high N:P ratio organic matter produced during nitrogen fixation in those systems. N-fixation in the Arabian Sea is documented but not much is known about the other two areas. The effect of a high N:P organic matter flux into the denitrification zone was investigated with a simple 3-box mode.
5 June, 17:30 (P4+P6 OP4)
Chemosynthetic processes as carbon source and greenhouse gases (GHG) cycling (N2O and CH4) in central Chile coastal upwelling L. Farías1,2,3, C. Fernández1, J. Faundez1,2 and M. Cornejo1 Laboratorio de Procesos Oceanográficos y Clima (PROFC), Universidad de Concepción, Casilla 160-C, Concepción, Chile. Email:
[email protected] 2 Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental (FONDAP-COPAS), Universidad de Concepción, Chile. 3 Departamento de Oceanografía, Universidad de Concepción, Chile. 1
In coastal upwelling regions overlying oxygen deficient waters such as off central Chile (36°S), chemosynthesis (the process by which certain microbes create energy through chemical reactions) has evolved to be an important photoautotrophic process in terms of C assimilation. It is also involved in the cycling of greenhouse gases (GHG) such as nitrous oxide (N2O) and methane (CH4). Coastal upwelling fertilizes and degasses the euphotic zone, but also creates suitable conditions for ammonium and methane oxidation processes in the water column. These two processes are responsible for N2O production and CH4 consumption, respectively. We studied carbon assimilation (light and dark 13C assimilation) associated with chemosynthetic processes along with other oceanographic processes and variables in the frame of the COPAS Time Series station (see www.copas.cl). In addition, measurements of N2O and CH4 allow reconstructing 5 and 1-years of monthly frequency evolution of these gases respectively. 143
Eastern Boundary Upwelling Ecosystems Symposium Vertical N2O distribution showed a clear seasonal pattern; profiles were nearly homogeneous throughout the water column in autumn and wintertime (may-july) known as “non upwelling” period, while profiles showed a strong N2O maximum at intermediate depths associated with oxycline during spring-summer (September to march) known as “upwelling” period (60% of the year). This last pattern showed a significant negative and positive correlation with oxygen and nitrate, respectively, suggesting that nitrification (ammonium oxidation) is involved in the N2O production. The highest fluxes were observed during active upwelling, confirming the importance of upwelling as an outgassing mechanism. Estimated air-sea fluxes ranged between -9 and 195 µmol m-2 d-1 during most of the year. The average annual flux of N2O (30 nmol m-2 d-1), scaled up to a representative area (~830 km2) was 0.4 Gg N2O yr-1 indicating the relevance of upwelling ecosystems in the global N2O budget. Vertical CH4 distribution showed CH4 levels increasing with depth, indicating that sediments and probably also the bottom water are sources of this gas. However, as the water column becomes more oxygenated throughout the year, methane can be consumed by methanotrophic micro-organisms. CH4 content in the water column and the concomitant efflux showed a positive relationship with the O2, i.e., high levels (up to 150 nmol L-1, during well oxygenated water column (winter time); whereas during spring-summer time low CH4 levels (~ 25-50 nmol L-1) were observed; suggesting that a CH4 consumption is intensified with low O2 concentrations, i.e., due to the oxidization of a high concentration of organic material generated by primary production during the coastal upwelling. In terms of carbon assimilation; dark 13C assimilation (DIC13C) along with study period ranged from 0.1 to 1.17 mg C m-3 d-1, representing up to 35% of total primary production; the reduction of dark 13C assimilation rates under the presence of specific metabolic inhibitor (e.g., ATU) suggests that nitrifying and/or methanotrophic microorganisms are responsible, in part, for these C assimilation rates present in the Chilean upwelling ecosystem. Our results suggest that N2O and CH4 contents and their effluxes have opposite relationship. Thus, the temporal variability of the GHG production and fluxes is not only associated to the wind effect in coastal upwelling areas but also in biogeochemical processes highly sensitive to oxygen levels.
5 June, 17:45 (P4+P6 OP5)
Living with the oxygen minimum zone (OMZ) in the Humboldt Current system: the case of Eucalanus inermis (Copepoda-Calanoida) P. Hidalgo1 and R. Escribano1 1 2
Instituto de Biologia Marina, Universidad Austral de Chile, P.O.X 160 C- Dichato, Concepción, 160 Chile. Email:
[email protected] Estacion de Biologia Marina-Dichato, Universidad de Concepción, Chile.
A shallow (<50 m) oxygen minimum zone (OMZ) is a prominent feature in the coastal zone off northern Chile in the Humboldt Current system. This layer restricts the vertical distribution and diel vertical migration of zooplankton. However, Eucalanus inermis, a large-sized copepod is able to enter the OMZ and even maintain its population within this habitat. We carried out seasonal comparative studies on the physiological responses of to surface oxygenated water and low oxygen water (<1 ml O2 ml-1) from the OMZ. We assessed egg production rate (EPR), growth rate (GR), grazing rate (HR), production of faecal pellets (FPPR) for both conditions, as well as temperature-dependent development rates. We found no seasonal differences in the physiological rates. Between oxyc and low-oxygen conditions there were no differences either, although egg production took place only under low-oxygen condition (within the OMZ). Therefore, population dynamics of this copepod is not negatively affected by the OMZ and this layer may provide ecological advantages in terms of shelter for predation from visual predators and from gelatinous zooplankton restricted to the oxyc layer. An ecological population model to describe and predict the interaction between this copepod and the OMZ system is being developed upon these in situ estimated rates. The work will ultimately attempt to predict the dynamics of this species upon remote forcing (e.g. ENSO variation and climate change) altering the distribution and intensity of the OMZ system in the eastern south Pacific. Climate variability and El Niño Oscillation: implications for natural coastal resources and management (CENSOR) Work Package 2. Center for Oceanography Research in the eastern South Pacific (FONDAPCOPAS), Universidad de Concepción. Pelagic Laboratory and Mesozooplankton (PLAMZ) Estación de Biologia Marina-Dichato, Universidad de Concepción. Instituto de Biologia Marina, Universidad Austral de Chile. 144
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 18:00 (P4+P6 OP6)
What key factors control phytoplankton spatial variability in upwelling regions? E. Machu1, Z. Lachkar2, N. Gruber2, V. Echevin3 and J. Arístegui4 IRD, 2 Rue de Tiznit, Casablanca, 20000, Morocco. Email:
[email protected] Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Switzerland. 3 LOCEAN, France. 4 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Spain. 1 2
Coastal upwellings associated with eastern boundary currents are responsible for important levels of primary and secondary productions sustaining high production of small planktophagous pelagic fish, like sardines and anchovies, reflected in worldwide fish catches. Since phytoplankton growth results from non linear processes, depending on mixing, nutrient availability, light, temperature, competition and interaction with consumers, we used coupled physical/biogeochemical models to simulate annual cycles of phytoplankton distribution within the four major upwelling ecosystems (Benguela, California, Canary and Humboldt). The Regional Oceanic Modelling System (ROMS) constitutes the eddy-resolving hydrodynamic platform, to which biogeochemical/ecological modules have been coupled. The complexity of these modules ranges from five nutrients, two phytoplankton, two zooplankton and two detritus compartments (PISCES) to the simplest version of this type of model, i.e. Nitrate-Phytoplankton-Zooplankton-Detritus (NPZD). We first evaluated the ability of the different biogeochemical/ecological modules in representing the spatial distribution of phytoplankton (i.e. the upwelling itself, the offshore subtropical gyre and the transition zone) by validating simulated surface chlorophyll distributions with satellite observations. Regenerated production seems to be necessary in order to better represent the transition between the eutrophic upwelling region and the oligotrophic subtropical gyre as well as over large continental shelves like the Saharan Bank. According to a set of modelling experiments, we will present the main factors controlling the seasonality of the phytoplankton distribution in the different eastern boundary currents, and will discuss the main differences that occur within the first trophic level dynamics.
5 June, 18:15 (P4+P6 OP7)
Nitrate supply and potential primary productivity estimates in four eastern boundary upwelling systems M. Messié1, J. Ledesma2, D. Kolber1 and F. Chavez1 1 2
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, 95039, USA. Email:
[email protected] Instituto del Mar del Peru, Peru.
Nitrate supply by coastal upwelling has been estimated in four eastern boundary regions (Benguela, California, Northwest Africa and Peru) by combining surface winds measured from space and in situ vertical nitrate profiles. We use a QuikSCAT 0.25°x0.25° weekly wind product to assess the seasonal vertical transport induced by wind forcing. The calculation is made from the coast to 150 km offshore and the wind-driven upwelling is partitioned into that contributed by Ekman transport and pumping. We assume that on the upwelling event time scale (days) the water brought to the surface originates from a depth of 60 m. Seasonal climatologies are used to estimate in situ nitrate concentration at 60m, and nitrate supply is calculated as the product of nitrate concentration times the vertical transport obtained from QuikSCAT. This represents the potential new production, i.e. the amount of nitrate available for phytoplankton primary production, for each region. Satellite winds are a tremendous improvement relative to climatologies generated from ship wind reports but are deficient in terms of near coastal winds. As such there are uncertainties in wind stress curl that primarily affect the estimates of Ekman pumping. The depth from which upwelled water originates is most certainly variable and could bias our estimates; sensitivity studies of varying the depth of source water are provided. In spite of these uncertainties, when our results are converted to primary productivity using a “coastal upwelling” f-ratio they compare quite favorably with satellite (SeaWiFS)-derived estimates of primary productivity. In this paper we report and compare the nitrate supply contributed by Ekman transport and Ekman pumping in the four regions. The latitudinal and seasonal distribution of nitrate supply is described and compared with SeaWiFS chlorophyll. Comparisons are made with the zonal/offshore extension of chlorophyll concentration of 1 mg/m3 as well as chlorophyll concentration itself. Spatial and temporal differences between physical (upwelling times nitrate concentration times the f-ratio) and biological (satellite chlorophyll algorithms) estimates of primary production will be discussed. 145
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 18:30 (P4+P6 OP8)
Seasonal upwelling along the west coast of India S.W.A. Naqvi National Institute of Oceanography, Dona Paula, Goa 403 004, India. Email:
[email protected]
In the Indian Ocean, the most intense upwelling occurs not along its eastern boundary, but in the northwestern sector (off Somalia, Yemen and Oman) during the summer monsoon. The water upwelled here advects about 1000 km offshore, causing widespread phytoplankton blooms. However, moderate upwelling also occurs along the west coast of India during this season, when the surface flow is directed toward the equator (as opposed to poleward flow during the winter monsoon). An undercurrent, typical of all eastern boundary upwelling systems, flows poleward at the same time. Upwelling along the Indian coast is not forced entirely by local winds. Moreover, unlike other eastern boundary upwelling systems, the cold, saline water is overlain by a warm, fresher layer arising from intense rainfall in the coastal zone, leading to strong stratification and poor ventilation of sub-pycnocline waters. High primary production (up to 6 g C m-2 d-1) and the consequent respiration completely strips near-bottom waters of their O2 content over large parts of the inner- and mid-shelf, triggering extensive denitrification north of about 12oN. This process begins in July and lasts till November. Within about a month of the onset of reducing conditions, all oxidized nitrogen forms are completely lost leading to sulphate reduction. H2S has been detected in concentrations reaching up to 21 µM. Substantial inter-annual changes in the intensity of anoxic conditions have been observed, and the available evidence suggests an intensification of O2 deficiency in recent years. As expected, NH4+ accumulates in high concentrations (up to 21 μM) in sulphide bearing waters. It is the upward diffusion of NH4+ rather than NO3- that fuels new production in the thin oxygenated layer overlying anoxic waters. In contrast, the primary production rate in the O2 depleted waters has been found to be low even when these waters are well illuminated. n unexpected feature of nitrogen cycling is the unprecedented accumulation of N2O (maximum 765 nM). Association of the high N2O concentrations with very high NO2(up to 16 μM) suggests production through denitrification. Transient build up of N2O probably occurs due to the low N2O reductase activity in shallow, rapidly denitrifying waters that are subjected to frequent aeration through turbulence. This sustains a high rate of emission of N2O to the atmosphere (up to 0.38 Tg N2O y-1). The atomic DIN/DIP ratio in oxic waters (13.74) is close to, while that in denitrifying waters (-79.1) is slightly lower than, the corresponding theoretical values (16 and 94.4). Anoxic waters are distinguished by excessive DIP due to the dissolution of the iron-oxyhydroxo-phosphates complex from the sediments. The same process also seems to lower the H2S/DIP ratio to 7.6 as against the expected value of 53. On the other hand, the observed H2S/NH4+ ratio (4.8) is higher than the theoretical value (3.3). This unexpectedly high value may result from the diffusion of NH4+ from sediments to the overlying bottom waters.
5 June, 18:45 (P4+P6 OP9)
Carbon flux and nitrate uptake in the Peru upwelling, September 1976 and March 1977: calculations from enzyme analyses T. Packard1,2,8, D. Blasco1, L. Codispoti3, M. Estrada1, J.C. Christensen2, J. Ammerman7, P. Coble4, R.C. Dugdale5, R. Barber6, M. Gómez8 and S. Torres8 Institut Ciències del Mar, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain. Email:
[email protected] Bigelow Laboratory for Ocean Science, USA. 3 Horn Point Laboratory of the University of Maryland, USA. 4 University of South Florida, College of Marine Science, USA. 5 Romberg Tiburon Center, USA. 6 Duke University Marine Laboratory, USA. 7 Institute of Marine and Coastal Sciences, Rutgers University, USA. 8 Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Spain. 1 2
The Coastal Upwelling Ecosystem Analysis (CUEA) program studied the Peruvian, upwelling system mainly in the March-April-May (northern hemisphere spring) period in the years 1972-1978. Rarely were studies made during the southern hemisphere spring (September-October-November). Now it is much clearer than previously, that the Peru upwelling strength intensifies in the southern-hemisphere winter and 146
Eastern Boundary Upwelling Ecosystems Symposium spring. Accordingly, the unpublished data from JASON Expedition to the Peru upwelling in September, 1976 takes on new significance. Here, we analyse unpublished succinate dehydrogenase, respiratory electron transport system, and nitrate reductase activity data from the surface and deep water at 15°S and calculate new production, as well as microplankton depth-profiles of carbon flux, phytoplankton nitrate uptake, respiratory O2 consumption, CO2 production, and the respiratory quotient (RQ). These calculations are compared with comparable calculations from the same location made on the R/V Wecoma expedition six months later (March 1977) and the R/V Melville-leg 4 Expedition 8 months later (May 1977).
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Eastern Boundary Upwelling Ecosystems Symposium
P4+P6 Posters Poster: P4+P6 P1
Benthic biomass responses to changes of organic matter fluxes induced by ENSO in the Peruvian coastal upwelling ecosystem E. Enríquez, D. Gutiérrez, L. Quipúzcoa, W. Serrano, D’L. Cuadra, R. Marquina, V. Aramayo and W. Yupanqui Instituto del Mar del Peru, Dirección de Investigaciones Oceanográficas, Casilla Postal 22, Callao, Peru. Email:
[email protected]
It was investigated the relationship between the interannual variability of deposition of organic matter at the seafloor, induced by contrasting ENSO phases, and the carbon biomass among benthic communities (macrofauna, metazoan meiofauna, Thioploca spp. and microbial bacteria) in the Peruvian coastal upwelling ecosystem. The study took place at a station located at 94 m depth (12°02.8' S, 077°17.1' W), 10 miles off Callao, during two periods: 2002-2003 (under a weak El Niño-EN) and 2004-2005/2007 (under normal and La Niña-LN conditions, respectively). Significantly higher contents of surface chlorophyll-a (a measure of phytodetritus deposition) were recorded in 2004-2005 (19.04 to 196.43 µg g-1 Chl a) and 2007 LN (32.36 to 830.81 µg g-1 Chl a), as compared with 2002-2003 EN (33.49 to 66.28 µg g-1 Chl a). The combined effect of high export production and water mass oxygen deficiency resulted in chemically reducing sedimentary conditions such as was showed by redox conditions at the sediment/water interface during 2004-2005 (-173,5 to -55,6 mV) and 2007 LN (-56,8 to -10,6 mV), whereas during 2002-2003 weak EN varied from –92,9 to 243,6 mV. The major benthic groups reacted in different ways to the increased or decreased organic matter fluxes associated to normal / La Niña and El Niño phases. Macrofaunal and Thioploca biomasses were significantly higher during the 2002-03 weak EN (0.06 ± 0.05 and 0.84 ± 0.47 gC m-2, respectively) than during 20042005 (0.01 ± 0.04 and 0.16 ± 0.20 gC m-2, respectively). During the 2007 LN, the macrofaunal biomass was also very low (0.01 ± 0.01 gC.m-2), while Thioploca biomass was highly variable (1.10 ± 0.82 gC m-2). Meiofaunal biomass increased from 2002-03 to 2004-2005 (0.08 ± 0.13 to 0.51 ± 0.10 gC m-2), while it reached 0.21 ± 0.11 gC m-2 during the 2007 LN; higher biomasses were explained by nematode populations. Finally, a dramatic increase of microbial biomass was observed in 2007 LN (37.82 ± 39.24 gC m-2) relative to the 2002-03 weak EN (9.09 ± 2.84 gC m-2). We interpret that, during normal / La Niña phases, microbial bacteria and nematofauna profit from the increased organic matter flux whereas macrofauna reduce its standing stock because it is not able to cope with the rapid oxygen depletion at the sediment/water interface. Instead Thioploca mats are more persistently developed under weak EN conditions, because of the favourable trade-off between moderate sulphide production in the sediments and nitrate content in the bottom water (reduced nitrate loss processes). During neutral or LN years, the increase of organic matter flux to the benthos is channelled to microbial bacteria that may rapidly hydrolize the particulate organic matter, making more organic matter compounds available to anoxia-tolerant benthic groups as nematodes.
Poster: P4+P6 P2
Nitrogen regeneration in the euphotic zone of the Peruvian upwelling and its contribution to primary production C. Fernández1,3, L. Farías1,2,3, M. Estrella Alcaman1 and M. Gallegos1,2 Laboratorio de Procesos Oceanográficos Física y Clima, Universidad de Concepción, Casilla 160-C, Concepción, Chile. Email:
[email protected] 2 Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental (FONDAP-COPAS), Universidad de Concepción, Chile 3 Departamento de Oceanografía, Universidad de Concepción, Chile. 1
The area off Peru is characterised by a permanent upwelling condition and high primary production, particularly between 16ºS and 4ºS in latitude. Also, high rates of organic matter remineralization enhance the formation and maintenance of a shallow and intense oxygen minimum zone (OMZ), which is a crucial feature in the local nitrogen cycle because of in situ denitrification and anammox. Organic matter 148
Eastern Boundary Upwelling Ecosystems Symposium remineralization is also responsible for providing a supplementary fraction of available nutrients in terms of nitrate and ammonium for the euphotic layer. Although potentially important in coastal areas, no measurements of nitrification or ammonium regeneration has been done (to our knowledge) in this particular system for more than 15 years while measurements of primary production are also sporadically reported. We present data collected during the 2005 KN182 cruise to the Peruvian upwelling. Measurements of primary production and nitrogen assimilation were complemented with experiments of ammonium regeneration and nitrification in the euphotic layer. Surface rates of primary production showed minimum values (below 10 mg m-3 d-1) at northern stations and increased toward the coast to reach values close to 200 mg m-3 d-1. Integrated carbon assimilation, showed coastal maximum values of up to 2 g m-2 d-1. Ammonium concentrations in the water column were generally above detection limit, even in surface waters where values often exceeded 40 nM. Nitrate concentrations, on the other hand, oscillated between less than 1µM in northern stations and 10 µM in coastal Peruvian waters. Along with high carbon assimilation, nitrogen uptake (in the form of nitrate and ammonium) showed high variability although ammonium uptake was generally higher than nitrate assimilation. Values of ρNH4 in the first 50 m often exceeded 50 nM d-1 (reaching 150 nM d-1), which suggest that the entire pool of ammonium can be metabolized in 24 hrs. Nevertheless, regeneration of this element showed even higher rates, generally surpassing the observed assimilation (e.g. 400 nM d-1 in northern stations). Rates of nitrification in the first 30 m were obtained at selected stations, ranging between 0 and 44 nM d-1. Values suggest that this excess of ammonium could be used by nitrifying communities for in situ regeneration of NO3 in the upper layer, fueling between 5 and 30% of surface NO3 utilization. Our results provide a coupled data set combining carbon and nitrogen cycling, which suggest that photoautotrophic activity in upwelling areas is not only fueled by “new” nitrogen but can also be supported by in situ regeneration.
Poster: P4+P6 P3
Anammox bacteria and the anaerobic oxidation of ammonium in the oxygen minimum zone off northern Chile A. Galan1, M. Veronica2, T. Bo2, W. Dagmar3, L. Gaute3, K. Marcel3 and U. Osvaldo1 University of Concepción, Cabina 7, Universidad de Concepción s/n, Concepción, Región del Bio Bio, 4070407, Chile. Email:
[email protected] 2 Nordic Center for Earth Evolution, Institute of Biology, University of Southern Denmark, Denmark. 3 Max Planck Institute for Marine Microbiology, Germany. 1
Anammox is the anaerobic oxidation of ammonium by nitrite and/or nitrate to yield N2. This process, along with denitrification, contributes to nitrogen loss in oxygen-deficient systems. Anammox is performed by a special group of bacteria belonging to the Planctomycetes phylum. However, information about the distribution, activity, and controlling factors of these anammox bacteria is still limited. Herein, we examine the phylogenetic diversity, vertical distribution, and activity of anammox bacteria in the coastal upwelling region and oxygen minimum zone off northern Chile. The phylogeny of anammox bacteria was studied using primers designed to specifically target 16S rRNA genes from Planctomycetes in samples that were taken during a cruise in 2004. Anammox bacteria-like sequences affiliated with Candidatus “Scalindua spp.” dominated the 16S rRNA gene clone library. However, 62% of the sequences subgrouped separately within this cluster and together with a single sequence retrieved from the suboxic zone of the freshwater Lake Tanganyika. The vertical distribution and activity of anammox bacteria were explored through CARDFISH (fluorescence in situ hybridization with catalyzed reporter deposition) and 15N labelling incubations, respectively, at two different open-ocean stations during a second cruise in 2005. Anammox bacterial CARD-FISH counts (up to 3000 cells ml-1) and activity (up to 5.75 nmol N2 L-1 d-1) were only detected at the station subjected directly to the upwelling influence. Anammox cell abundance and activity were highest at 50 m depth, which is the upper part of the OMZ. In this layer, a high abundance of cyanobacteria and a marked nitrogen deficit were also observed. Thus, our results show the presence of a new sub-cluster within the marine anammox phylogeny and indicate high vertical variability in the abundance and activity of anammox bacteria that could be related to an intensification of carbon and nitrogen cycling in the upper part of the OMZ. 149
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P4+P6 P4
Nitrous oxide (N2O) exchange across the air-sea water interface off North Chile (21ºS – 30ºS) under the influence of the oxygen minimum zone M. Gallegos1,2 and L. Farías1,2,3 Laboratorio de Procesos Oceanográficos Física y Clima, Universidad de Concepción, Casilla 160-C, Concepción, Chile. Email:
[email protected] 2 Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental (FONDAP-COPAS), Universidad de Concepción, Chile. 3 Departamento de Oceanografía, Universidad de Concepción, Chile. 1
The recognition that N2O concentrations are increasing in the atmosphere, therefore playing a key role in both the stratospheric ozone and the tropospheric heat budgets, has stimulated the study of oceanic N2O production processes. The ocean contribution of N2O to the atmosphere can be as high as 20% of the total global contribution, from which coastal upwelling regions represent the main areas of GHG efflux towards the atmosphere. Most of these areas are associated with oxygen minimum zones which favor processes involved in the N2O cycling, such as nitrification and denitrification. This study focuses on the influence of low oxygen waters on N2O cycling, with particular emphasis on upwelled waters associated with the Equatorial Subsurface Water (ESSW) and the Peru-Chile Undercurrent that define the oxygen minimum zone in the eastern south Pacific (OMZ). Measurements of dissolved O2, N2O, nutrients, and other oceanographic variables were carried out off northern Chile (~ 21°S) along a transect from the coast to the ocean. The vertical distribution of dissolved O2 and N2O shows a sharp drop in oxygen concentrations with depth (30 to 70 m), from 100% saturation to less than 5% saturation, generating a sharp shallow oxycline that gets deeper off shore. The distribution of nitrous oxide had two maxima. A narrow maximum was located between 20 and 90 m while another extended between 400 and 1000. However, the core of the OMZ is depleted in this gas, probably due to consumption through denitrification. The first maximum was always confined in the oxycline and N2O levels decrease from the coast to the ocean (from 90 to 40 nM). This pattern is associated with vertical advection due to coastal upwelling which in turn affects directly the oxygen gradient. Most N2O accumulation is located on a 30-50 m thick depth range and at oxygen levels over 50-10 µM, where the strong gradient seems to be the ideal site for living nitrifying and denitrifying bacteria producing N2O. These high and quasi-permanent subsurface N2O peaks not only constitute a large source of N2O towards the atmosphere (8.61 and 177 µmol/m2/d1) but also they are a source of electron acceptors for denitrifying activity in the OMZ core and have concomitant climatologic and ecological consequences.
Poster: P4+P6 P5
Benthic nitrogen cycling associated with the oxygen minimum zone (OMZ) variability of the upwelling Humboldt ecosystem off central Peru M. Graco1, G. Lavik2, G. Flores1, L. Jesús1, D. Gutiérrez1, O. Morón1 and M. Kuypers2 1 2
Instituto del Mar del Peru, Esq. Gamarra y Gral Valle Chuchito- Callao, Peru. Email:
[email protected] Max- Planck-Institute for Marine Microbiology, Germany.
The Humboldt upwelling ecosystem is one of the most productive areas in the ocean, characterised by an extense and intense oxygen minimum zone (OMZ), that intercept the continental shelf creating large suboxic-anoxic enviroments. These conditions have several impacts in biological communities and in the biogeochemical cycles. In fact, globally, 30-50% of the total nitrogen loss occurs in OMZs and could deplete nitrate limiting primary productivity. Additionally, events such as El Niño, that present a strong signal off Peru, impact significantly the extent of the OMZ and also the productivity rates. Only few studies have dealt with nitrogen dynamics and the OMZ variability under El Niño influence in the upwelling areas. Until now data on nitrogen lost from the continental margin of the Peruvian coastal upwelling ecosystem has not been available. This work focuses on the loss of N magnitude and variability in the coastal margin off central Peru(Callao, 12°02'S) with a seasonal and interannual resolution. Denitrification and anammox rates (isotope paring methods) were analysed during summer-fall and winter of 2006 and 2007. I n order to explore the coupling between sedimentary nitrogen cycling and oceanographic conditions, these results were combined with in situ measurements of water column (oxygen, nutrients, clorophyll a, temperature, salinity) and primary 150
Eastern Boundary Upwelling Ecosystems Symposium productivity. In order to determine the seasonal and interannual variability (El Niño influence) 1996-2007 time series of dissolved oxygen, OMZ distribution, and nutrients data were examined in the study area. Our in situ experiments indicate that the continental margin off Peru have high loss of N ( up to 10 mmol m-2 d-1). Rates of N2 formation are comparably high for coastal areas and other upwelling systems as Namibia and central Chile (<3 mmol m-2 d-1). The nitrogen lost is explained principally by denitrification activity but also associated with a potential anammox production (up to 50%). A significant interannual variability was observed, associated with El Niño 2006 (weak), determining low N lost rates (< 0.5 mmol m-2 d-1) coincident with a strong deepening in the upper boundary of the OMZ, oxygen deficient waters are found below 100 m depth (usually at 20 m), and low primary productivity rates (<0.5 mg C m-2 d-1). The historical data of the area show that Nitrogen deficits (N*) ranged from negative values-0 up to 35 μmol N L-1. High values indicate the largest N lost in shelf bottom waters and lowers values were associated with El Niño conditions. The results indicate that the Humboldt upwelling system is a highly dynamic system with important interannual changes in the distribution of oxygen deficient waters and primary productivity rates that affect the nitrogen dynamic. The potential loss of nitrogen off the coastal of central Peru reflects the tight coupling between the pelagic and benthic conditions and between local and remote processes.
Poster: P4+P6 P6
Modelling new primary production (pnew) through temperature-nitrate relationship along Baja California peninsula B. Hernández-de la Torre1, M. Martínez-Gaxiola2, G. Gaxiola-Castro2, R. Hernández-Walls3 and R. AguirreGómez4 Instituto Nacional de Ecología, (INE), Km 107 Carretera Tijuana-Ensenada, Casa Móvil No. 8, Ensenada, Baja California, 22860, Mexico. Email:
[email protected] 2 Centro de Investigación Científica y de Educación Superior de Ensenada, Mexico. 3 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Mexico. 4 Instituto de Geografía, Universidad Nacional Autónoma de Mexico, Mexico. 1
Studies of regionalisation or Marine Management in Mexico have been affected by the lack of a method that integrates spatial and temporal variability in the euphotic zone. Approaches in most of the cases have been general and descriptive analyses. The conceptual base of the relationship between nutrients supply and marine ecosystem function is based on Pnew. It is increasingly accepted that Pnew is not only a product, but offers a possibility to understand ecosystem function. Due to reduced experience in Mexico about marine management, we propose to use Pnew as a useful alternative for delimiting trophic areas as a basis for marine regionalization. We used data from CalCOFI (1949-2002) and IMECOCAL (19972005) regions in Baja California peninsula to obtain climatological profiles of sea surface temperature. We classified these profiles (200 m depth) each 0.5°C and based on MEI, we identified El Niño, La Niña and normal years. Based on climatologic temperature profiles we calculated the nitrate values, according to Hernandez et al. (2002). Finally, we obtained Pnew in depth as multiplicative result of the f-ratio and the total primary production (Ptotal). Our results show water dynamic behavior from coast to open ocean and from north to south, with peaks of Pnew between 30 and 50 m depth. We suggest that this method can be a useful tool for marine management.
Poster: P4+P6 P7
Hydrological variability of upwelling areas along the morocccan atlantic coast from 2001 to 2007 A. Makaoui, A. Orbi, K. Hilmi, J. Larissi, A. Benazzouz and S. Zizah Institut National de Recherche Halieutique, Oceanography and Aquaculture, 2 Rue Tiznit, Casablanca 20000, Morocco. Email:
[email protected]
The upwelling of the Moroccan Atlantic coast is directly under the influence of the anticyclone of the Azores and the zone of intertropical convergence (ITCZ). Four upwelling areas are identified along the Moroccan Atlantic coast located between: Cape Cantin-Cape Ghir, Cape Draa-Cape Juby where the upwelling occurs 151
Eastern Boundary Upwelling Ecosystems Symposium during the summer, and Cape Boujdor-Dakhla and Cape Barbas-Cape Blanc where it appears throughout the year. This study is interested in the recent distribution of the physicochemical parameters and their seasonal variability in the four zones for the period between 2001 and 2007. This hydrological distribution will enable us to follow the intensity and the interannual change of coastal resurgences which have an impact on the evolution of the pelagic ecosystem of the Moroccan continental shelf.
Poster: P4+P6 P8
Denitrification in the eastern boundary upwelling zone off India H. Naik and W. Naqvi National Institute of Oceanography, Dona Paula, Goa, India. Email:
[email protected]
The Arabian Sea contains one of the world’s three large mesopelagic oxygen minimum zones (OMZs) within which O2 concentrations are low enough to support denitrification. This makes the Arabian Sea a globally important sink of combined nitrogen. In addition to the perennial open ocean suboxic zone, there also exists a seasonal suboxic zone over the western continental shelf of India, which is of natural origin. During the southwest monsoon, upwelling brings poorly oxygenated, nutrient-rich subsurface waters over the western Indian continental shelf close to the sea surface. But these waters are generally overlain by thin (~ 5-10 m thick) fresher water lens resulting from local precipitation making the water column highly stratified. This supports enhanced subsurface biological production that attains the maximal value of ~6 g C m-2 d-1 (highest value observed in the Arabian Sea). The eventual decay of organic matter leads to the removal of residual O2. The facultative bacteria then utilize the NO3- followed by SO42- as oxidants for degrading organic matter. Denitrification over the mid-shelf is often associated with large accumulation of NO2- (up to 16 µM) and N2O (up to ~ 0.8 µM) usually in the upper portion of the suboxic layer, with the removal of oxidized nitrogen forms occurring in the deeper anoxic portion. Pelagic denitrification rates were estimated from repeat observations at a fixed station (the Candolim Time Series, CATS, site located off Goa at a water depth of ~28 m). The average rate calculated is 0.8 µmole NO3- l-1 d-1. The overall rate for the entire shelf experiencing suboxia (area ~200,000 km2) comes to 1.3-3.8 Tg N yr-1, which corresponds to the 4-12% of the denitrification within the perennial suboxic zone. We have also measured the sedimentary denitrification rates (SDR) at depths varying from 29 to 300 m following the acetylene block technique. SDR varied over the range 0.17-1.45 pmole NO3- cm-2 s-1 with the maximum occurring over the mid-shelf. The observed rates are quite modest and comparable with similar estimates from other areas. When extrapolated to the total area of continental shelves in the Arabian Sea (0.51 x 1012 m2), the total benthic denitrification rate works out to be 0.38-3.5 (average 1.33) Tg N yr-1, which is of the same order of magnitude as the pelagic denitrification rate over the Indian Shelf. Thus, benthic denitrification over the Arabian Sea continental shelf acts as a moderate sink for combined nitrogen. Although denitrification has a potential to counter inputs of combined nitrogen due to human activities, the fact that a substantial fraction of nitrogen is reduced to N2O means that this process is of little environmental benefit.
Poster: P4+P6 P9
Exploring measurements of potential respiration T. Packard1,2,3, M. Alcaraz1 and M. Gómez3 Instituto de Ciencias del Mar, Paseo Marítimo de la Barceloneta 37-49, 08003 Barcelona, Spain. Email:
[email protected] Bigelow Laboratory for Ocean Science, W. Boothbay Harbor, Maine 04575, USA. 3 Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira., 35017 Las Palmas de G.C., Canary Islands, Spain. 1 2
Do upwelling systems pump organic matter into the subsurface waters and into offshore waters? Is the biosphere losing nitrogen to anammox and denitrification or is it in balance with nitrogen fixation and anthropogenic inputs? Is the ocean net autotrophic or heterotrophic? These questions cannot be resolved without accurate measurements of the physiological processes involved and yet our methodology lags far behind our curiosity and the demand to monitor our rapidly changing planet. This situation cries out for methods development. For this reason, as in Gomez et al (1996), we continue to explore the use of 152
Eastern Boundary Upwelling Ecosystems Symposium the respiratory electron transport system (ETS) as a measure of potential respiration (Φ) and a proxy for respiration (R). Here we demonstrate how kinetic ETS assays document reaction-rate time-courses, cuts reaction-time in half, and eliminates turbidity blanks; why substrate blanks do not measure ETS activity and why a Michaelis-Menten Vmax should be measured instead; and the biochemical meaning of R/Φ in seawater. We also present new data on the molar specific absorption coefficient for the tetrazoliums, INT and CTC. Finally we discuss the need for standards for ETS activity.
Poster: P4+P6 P10
Oxygen Minimum Zones (OMZs): intense reserves of remineralized CO2 close to the surface ocean A. Paulmier1,2, D. Ruiz-Pion2, I. Masotti3 and V. Garçon2 LEGOS/CNRS, 18 av. Ed. Belin, 31401 Toulouse cédex 9, France. Email:
[email protected] LOCEAN/UPMC, 4. pl. Jussieu, 75005 Paris, France. 3 LSCE/CEA, France. 1 2
OMZs, known as suboxic layers mainly localised in the eastern Boundary upwelling systems (e.g. Humboldt, California, Benguela), have been expanding since the beginning of the 20th century, probably due to both circulation and primary production changes predicted as an effect of global warming. OMZs are also known to contribute significantly to the oceanic production of N2O, a greenhouse gas (GHG) ~300 more efficient than CO2. However, the contribution of the main OMZs on the oceanic CO2 subsurface reserve still remains to be established. To test the hypothesis of a positive feedback on the greenhouse effect, the CO2 structures associated with the OMZs were determined over the whole ocean. To achieve this, we jointly examined the international O2 and CO2 databases for the main open ocean OMZs, along with simultaneous O2 and CO2 data collected during 4 cruises and a monthly monitoring (2000-2002) in one of the shallowest OMZ off Chile. High CO2 (>2225 μM, up to >2400 μM) has been reported over the whole OMZs thickness, allowing us to define a Carbon Maximum Zone (CMZ), potentially produced by a local high New DIC associated with a specific aerobic remineralization at the oxycline, 2-5 times more intense than in the oxygenated ocean.
Poster: P4+P6 P11
Effects of upwelling, tides and biological factors in the inorganic carbon system in San Quintín Bay, Baja California, Mexico M. Ribas-Ribas1, J.M. Hernández-Ayón2, V. Camacho-Íbar2, A. Mejía-Trejo2, A. Cabello-Pasini2 and R. Durazo-Arvizu3 University of Cadiz, CASEM. República Saharahui s/n, Puerto Real , Cádiz, 11510, Spain. Email:
[email protected] Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Mexico. 3 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Mexico. 1 2
San Quintin Bay (SQB) is a hypersaline coastal lagoon located in the arid north-western coast of Baja California Peninsula, Mexico (30º27’N, 116º00’W). It covers an area of approximately 42 km2 and has a mean depth of 2 m. SQB is y-shaped, with an eastern arm locally known as brazo San Quintin (bSQ), and a western arm known as Bahia Falsa (BF). The neighboring ocean, under the influence of California Current, is a typical wind-driven coastal upwelling system. The main objectives of the present work were to evaluate the effect of physical (upwelling and tides, mainly) and biologic process (seagrass, fitoplancton, seaweed and oyster culture) in pH, dissolved inorganic carbon (DIC) and dissolved oxygen (DO). Water samples were collected in SQB during May- July, 2005 at twenty stations. At each station, DIC and salinity were obtained. Samplings were carried out during high tides. Data Flow were used with chlorophyll, dissolved oxygen, temperature, salinity and pH sensors and a GPS. In addition, temperature measurements were registered continuous in three fixed station in the bay. These termographs allowed to determinate the presence and reach of the upwelled water into the Bay. It is known that during the period when the sampling was done the wind blew hard from the northwest. This fact and the coast orientation are on the side of strong upwelling. The combination upwelling-tides conditions played an important role in the pH, DIC and DO distribution along the Bay. Dissolved inorganic carbon (DIC) were up to 2030 μmol kg-1 at the inner ends of the Bay. These high values fit in with the lowest pH values (≈8). High carbon transport occurs when upwelling coincide with spring tides. The concentration of DIC in the mouth of the Bay and 153
Eastern Boundary Upwelling Ecosystems Symposium Bahía Falsa was controlled for dynamic mixing process. On the other hand, DIC decreased until 1800 μmol kg-1 in bSQ due to seagrass and the high residence time of this area. It was found that the 85% of the Bay acted as a source of CO2 to the atmosphere due to the high concentration of CO2 of the upwelled water. In contrast, the seagrass Zostera marina consumed both CO2 and HCO3- so the pCO2 in the inner arm of bSQ was below the equilibrium value. The residence time of BF was less than one week so dissolution or precipitation effect in the DIC due to oyster culture was not observed.
Poster: P4+P6 P12
Iron in the upwelling area of California Gulf J.A. Segovia Zavala1, F. Delgadillo Hinojosa1, M.L. Lares Reyes2, A. Tovar Sánchez3 and S.A. Sañudo Wilhelmy4 Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Km. 103 Carr. Tijuana-Ensenada, Ensenada, B.C., Mexico. Email:
[email protected] 2 Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada, Mexico. 3 Instituto Mediterráneo de Estudios Avanzados (IMEDEA), Islas Baleares, Spain. 4 University of Southern California, Department of Biological Sciences and Department of Earth Sciences, USA. 1
The Gulf of California (GC) is located in the Pacific eastern boundary upwelling ecosystems and is one of the most biologically productive areas (1000 to 4000 mg C m-2 d-1) in the world ocean. Physical processes play an important role in determining the biological productivity in this ecosystem. Upwelling occurs off the eastern coast with northwesterly winds (winter conditions), and off the Baja California coast with southeasterly winds (summer conditions). However, the main continuous upwelling events are in the midriff islands region of the GC, which is driven by tidal pumping which increases the availability of inorganic nutrients near the surface layer. In contrast to the extensive studies on nutrient cycling, little is known about the cycling of dissolved Fe (Fed) in the GC. Therefore, the processes controlling the spatial and temporal distribution of Fe in the water column and upwelling zone of the GC have not been studied. In this research we report new data (May, 2003) on Fed concentrations in a series of stations located in one of the most productive regions of the GC. Dissolved Fe was preconcentrated using organic extraction. The data presented here demonstrates the complex nature of Fed in the GC (upwelling, aeolian input, sediment input). For example, subsurface Fed at northern station was 3 and 4 nM for the upper 100 m, whereas at southern stations, the same concentrations were recorded at 250 and 400 m depth, respectively. Thus, Fed vertical distributions show that waters were moving from at least 400 m to shallower depths due to mixing over the sill. The average Fed concentration in the upper 200 m of the area of study was 2.0 nM ± 1.72 and ranged from 0.07 to 7.21 nM. These concentrations are generally higher (up to 27 times) than those measured in surface waters of the Eastern North Pacific. In the upper water column (aeolian input), we found relatively high Fed concentrations (> 5.0 nM), which are consistent with previously published values for the other inland seas such as the Mediterranean, although slightly lower than those reported for the Alboran Sea. The residence time of Fed at the surface layer was 2.82 ± 0.60 days, suggesting that this element is quickly removed from the water column.
Poster: P4+P6 P13
Biogenic, textural and detritic composition of laminated sediments from Lima and Pisco basins, Central Peru P. Tapia1,2, F. Velazco1, A. Sifeddine3, L. Ortlieb3 and D. Gutiérrez1 Instituto del Mar del Peru, Esquina Gral Gamarra y Valle s/n, Chucuito, Callao, Peru. Email:
[email protected] Universidad Peruana Cayetano Heredia, Facultad de Ciencias y Filosofía, Dept. Ciencias Biologicas, LID, Peru . 3 UR Paléotropique, IRD, France. 1 2
Five box cores retrieved from the shelf off Pisco and Callao and taken from water depth between 100 m to 300 m contain sandy silt and clayey silt sediments with mm to cm-scale bands, laminations and bioturbated zones. These sites are well suited to preserve past records because they are within the oxygen minimum zone with dysoxic sediments underlying upwelling regions in the Peru Current along the coastal margin. Usually, light-dark couplet laminations occurred heterogeneously throughout the core length. Age models from cores B0405-06 (Pisco) and B0405-13 (Callao) based on excess 210Pb activities, bomb-derived 154
Eastern Boundary Upwelling Ecosystems Symposium Am signals, and sediment structures derived from historically well-known seismic events, suggests a sedimentary record of approximately 600-yrs. A semi-quantitative analysis on the main biogenic, detritic and textural components were performed in 151 smear slides from individual laminae samples from these 5 cores in a Nikkon Eclipse Petrographic Microscope at a total magnification of 500X. We registered relative abundances of textural, organic matter, mineral, as well as siliceous and carbonated organism remains. Our data indicates that the dark laminae are composed of low values of sand (1.3%), higher values -with respect to the light laminae- of organic matter (25.4%, areal slide distribution); and lower values of diatoms (34.3%) and carbonate minerals (5.3%). Contrary, the light laminae contained higher values - with respect to the dark laminae- of sand (7.9%), lower organic matter (16.4%), and higher values of diatoms (41.3%) and carbonate minerals (8.9%). We also note a small population within the light laminae formed by fine biogenic sand composed of large diatoms of the genus Coscinodiscus. Thin section analysis shows also heterogeneous distribution of biogenic, detritus, mineral and organic matter distribution. In the case of microfossils, diatom remains are concentrated in fecal pellets, laminae and small lenses; foraminifers are encounter in carbonate-preserved zones, and calcareous nannoplankton rarely occurs. Thus, there are high variability between lamina components, their distribution, sediment color and hue along the core length. Nevertheless, the amount of organic matter (aggregated and disperse) is directly related to the laminae color. 241
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Eastern Boundary Upwelling Ecosystems Symposium
P5
Near shore and estuarine processes related to EBUS
3 June, 15:15 (P5 KNS)
The impacts of upwelling on nearshore and intertidal communities in the Benguela upwelling ecosystem G. Branch Marine Research Institute, Zoology Department, University of Cape Town, Rondebosch 7701, South Africa. Email:
[email protected]
There is a rich history of research on the Benguela upwelling ecosystem, and in the overview I focus on the effects of upwelling on nearshore and intertidal systems. At the largest (regional scale), the Benguela is characterised by high productivity, high biomass, low diversity and low endemicity of most groups of organisms. Upwelling is, however, not uniformly distributed in space. The largest of the upwelling cells, situated off Lüderitz near the border between South Africa and Namibia, seems to act as a barrier to dispersal between the southern Namaqua cold temperate province and the northern Namib cold temperate province, as is evidenced from data on the rates of dispersal and spread of an alien mussel, Mytilus galloprovincialis. The two provinces also differ in the temperal regularity of upwelling, with constant, almost year-round upwelling in the north, and highly seasonal, pulsed upwelling in the south. Wind-driven upwelling generates nutrient-rich cold waters that fuel the high productivity, but the system is also spatially and temporally highly variable. Differences in community composition and population dynamics reflect this. Mismatches between the rates of primary production and consumption by primary consumers lead to excess productivity at times, and to bottlenecks in the food web. High productivity associated with upwelling is a two-edged sword. While it fuels high biomass, it also exports materials from the shore, influencing the spatial availability of food particles and the dispersal of larvae – both of which have bottom-up effects on communities. Mechanisms that appear to allow larvae to return to the shore include upwelling itself as well as downwelling and internal waves. Excess productivity also leads to depletion of oxygen and even the generation of hydrogen sulphide, with catastrophic effects on intertidal and shallow-water organisms, including mass stranding of thousands of tons of rock lobsters and fish. Disturbance is thus a feature of the system. Estuaries appear to serve as refugia for nearshore fish during times of stress, but only for those species that are classed as ‘estuarinedependent’. Species that are ‘estuarine-independent’ seem incapable of locating or making use of estuaries in this manner. High physical variability is associated with low diversity, generating a pattern that is contrary to that normally predicted from latitudinal gradients. Superimposed on short-term day-to-day and mediumterm inter-annual changes, there is now good evidence of long-term climatic changes that are influencing the distribution of organisms, with profound consequences for the dynamics of ecosystems. These are exemplified by alteration in ecosystem structure and function revolving around an shifts in the distribution of rock lobsters, kelp, limpets, anchovy and pilchards – with serious socio-economic consequences. The story of the Benguela is thus one of riches of productivity and biomass, mixed with poverty of diversity and endemicity – both explicable in terms of the tempero-spatial variability of physical conditions.
3 June, 15:45 (P5 OP1)
Physical and ecological consequences of relaxation in coastal EBUS waters J. Largier Bodega Marine Laboratory, University of California Davis, PO Box 247, Bodega Bay, California, 94923, USA. Email:
[email protected]
In areas characterised by strong upwelling winds, brief weak-wind periods are critical in allowing for a relaxation of hydrographic structures that lead to important ecological consequences in coastal waters. As synoptic variability and relaxation events are typical of EBUS, some comparison between locations will be developed through a review of existing data from California, Chile, Spain and South Africa. However, primary focus will be on the mid/inner shelf waters in northern California (data from WEST, NCCCS, CODE, COCMP), where significant effects of relaxation have been documented. The physical consequences of 156
Eastern Boundary Upwelling Ecosystems Symposium relaxation include an absence of offshore surface Ekman transport, a weakening or reversal of alongshore flow, and an increase in near-surface stratification. Ecological consequences include phytoplankton blooms, recruitment of meroplankton, and elevated concentration of land runoff nearshore. The specifics of physical responses depend on local factors, including wind stress patterns, coastal topography, and runoff, while ecological responses depend on the interaction of these physical structures with specific properties of local plankton populations. The intent of this paper is to stimulate dialogue on similarities and differences of nearshore responses to relaxation in EBUS – both within and between systems.
3 June, 16:00 (P5 OP2)
Natural experiments in climate change: impacts of climate variation on coastal food webs B. Menge and F. Chan Oregon State University, 3029 Cordley Hall, Corvallis, Oregon, 97331-2914, USA. Email:
[email protected]
Determination of the effect of climatic fluctuations on coastal ecosystem dynamics can be a key tool in understanding the likely impacts of long-term climate change. Using long-term datasets from rocky intertidal habitats and adjacent coastal waters, we examine the relationship between ENSO (El Niño-Southern Oscillation), PDO (Pacific Decadal Oscillation), and NPGO (North Pacific Gyre Oscillation) events and community pattern and process. Climate events were quantified using daily, monthly or yearly averages of indices for each event. Overall, NPGO (reflects wind variation) had strong but spatially and temporally variable associations with phytoplankton concentration and recruitment of mussels and barnacles. PDO and ENSO (reflects thermal variation) were strongly associated with recruitment and growth of the dominant competitor for space in rocky intertidal communities, the mussel Mytilus californianus. Abundance of barnacles but not mussels increased with higher phytoplankton and higher recruitment rates, and higher predation by sea stars on mussels and barnacles was associated with higher recruitment and higher phytoplankton, suggesting possible impacts at higher trophic levels, and ultimately, in ecosystem dynamics. Mechanisms underlying these effects are complex, and driven in part by effects of climate on the strength of upwelling, with resulting and interdependent effects on sea water temperature, nutrients, phytoplankton, filter-feeder growth, and prey abundance. Contrasting predictions of the effect of climate change on coastal ecosystems by climatologists and counteracting effects of mechanisms within each of a warming or cooling coastal climate scenario make forecasting difficult, but the likely overall effects of warmer coastal waters seem more strongly negative than those of cooler coastal waters.
3 June, 16:15 (P5 OP3)
Indices for the intensity of upwelling-induced variability in shallow inner-shelf environments F. Tapia1, S. Navarrete1, B. Menge2, M. Castillo1, S. Gaines3, J. Largier4 and J. Castilla1 Departamento de Ecología & Estación Costera de Investigaciones Marinas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile. Email:
[email protected] 2 Department of Zoology, Oregon State University, USA. 3 Department of Ecology, Evolution/Marine Biology & Marine Science Institute, University of California, Santa Barbara, USA. 4 Bodega Marine Laboratory, University of California Davis, USA. 1
Interactions between physical and biological processes taking place in the coastal ocean have far-reaching consequences for the structure, dynamics and geographic distribution of marine populations. Coastal upwelling, and the spatial-temporal variability in its intensity, may profoundly affect local dynamics, renewal and connectivity among benthic marine populations and entire communities. Consequently, indices of upwelling intensity have been extensively used as ancillary environmental information in numerous studies. However, available mesoscale indices for upwelling intensity lack the spatial resolution needed to characterize and compare inner-shelf regimes of upwelling-induced variability at small scales (1-10’s km), 157
Eastern Boundary Upwelling Ecosystems Symposium which is often required to test relevant hypotheses in ecology, conservation, and management. We present a set of quantitative indices that may resolve small-scale differences in the intensity with which upwelling is perceived by intertidal communities. Indices were formulated to capture local differences in the variability of inner-shelf SST anomalies produced by the intensification of upwelling-favourable winds, and were used to classify sites separated by distances as short as 2 km, and spanning ~15 degrees of latitude along the coast of Chile and the western United States. Besides resolving small-scale variability in the environmental regime induced by coastal upwelling, our goal was to devise indices that may be calculated simply from time series of in situ sea surface temperatures (SST), so as to maximise the number of sites that may be compared within and among upwelling regions. To validate the indices, in situ estimates of cross-shelf transport were obtained for sites off the Oregon and California coast, where nearshore ADCP measurements were gathered concurrently with inner-shelf SST data. Our results indicate that upwelling variability may indeed be perceived at shallow subtidal habitats, and that one of the simplest indices calculated from in situ SST series, namely the mean duration of cooling events over an upwelling season, may be a good proxy for the offshore transport of surface waters. We use this index to analyze the correlation between small-scale structure in upwelling intensity and community attributes such as recruitment, coverage, and biomass of benthic algae and invertebrates.
3 June, 16:30 (P5 OP4)
Upwelling control on nutrient dynamics in San Quintin Bay (Mexico), a hypersaline a coastal lagoon: from short term to interannual variations V. Camacho-Íbar1, R. Durazo-Arvizu2, A. Souza3, E. Santamaría-del-Angel2, J.M. Hernández-Ayón1, A. Mejía-Trejo1, L. Aveytua-Alcázar1 and E. Ortíz-Campos1 Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Apdo. Postal 453, Ensenada, Baja California, Mexico 22830. Email:
[email protected] 2 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Mexico. 3 Proudman Oceanographic Laboratory, United Kingdom. 1
San Quintin Bay (SQB) is a Mediterranean-climate, hypersaline coastal lagoon in NW Mexico, strongly influenced by wind-induced upwelling events from the adjacent California Current System. Sampling campaigns were carried out in 2004 and 2005 in order to evaluate the role of ocean inputs on nutrient dynamics in SQB. During the strong upwelling period (late spring-early summer), after an upwelling event, sharp nitrate concentration gradients can be observed with values up to 15 μM at shelf stations and values less than 1 μM at the inner ends of the lagoon. Nitrate concentrations abruptly decrease as soon as ocean water enters the lagoon, indicating an intense uptake of “new” nitrogen by primary producers (phytoplankton, Ulva sp. and eelgrass Z. marina). Nitrate uptake rates near the mouth of the lagoon up to 4 mmol/m2/d were estimated by means of a box model. During relatively weak upwelling conditions (late summer), nitrate imports to the lagoon are weak and the dissolved inorganic nitrogen (DIN) pool is dominated by ammonium. During both periods, the inner arms show a net accumulation of dissolved organic nitrogen (DON), with concentrations between 15 and 25 μM exceeding those of DIN. Exports of DON apparently do not balance imports of DIN and particulate nitrogen, thus the bay is likely a net sink of N through denitrification. Results will be presented showing not only a strong interannual variation on nutrient supply to SQB between spring 2004 and spring 2005, but also a sharp latitudinal contrast on nutrient availability along the California Current system during spring 2005. As registered within SQB, in spring 2005 coastal waters off the north of the Baja California peninsula showed a nutrient enrichment associated with a positive anomaly on upwelling intensity. By contrast, during the same period a delay in the onset of upwelling conditions in the north of the California Current system caused anomalously low nutrient concentrations in that region. Positive chlorophyll-a anomalies during May-June 2005 were observed not only off SQB, but in the whole of northern part of the Baja California peninsula. Nitrate budgets using a box-model indicate that the supply of nitrate from the ocean to SQB was three times higher in spring 2005 than in spring 2004, showing that the supply of nutrients from the ocean to coastal lagoons and estuaries along the NE Pacific coast can have intense interannual variations related not only to El-Niño / La Niña conditions. 158
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 16:45 (P5 OP5)
Similarities between harmful algal bloom hot spots in eastern boundary current systems: the importance of retention to red tides R. Kudela1, J. Ryan2, V. Trainer3, G. Pitcher4, T. Moita5 and F. Figueiras6 Ocean Sciences Department, University of California, Santa Cruz, CA 95064, USA. Email:
[email protected] Monterey Bay Aquarium Research Institute, USA. 3 NOAA Fisheries, Marine Biotoxins Program, Northwest Fisheries Science Center, USA. 4 Marine and Coastal Management, South Africa. 5 INIAP - Instituto Nacional de Investigação Agrária e das Pescas, Portugal. 6 Instituto de Investigaciones Marinas, Spain. 1 2
Eastern boundary current upwelling systems, similar to all other marine environments, are increasingly susceptible to the proliferation and negative effects of harmful algae ranging from illness and death due to direct toxic effects, environmental degradation due to, for example, increased biological oxygen demand, direct impacts on fisheries, “nuisance” effects such as discoloration of the water, and more subtle changes to the ecology of these systems. Seasonal succession of microplankton in upwelling systems follows the general pattern of coastal temperate seas, with diatom dominance in spring, a progressive contribution of heterotrophic components during summer and a major contribution of dinoflagellates in late summer and early fall. This assemblage structure will expand and contract in response to pulses of upwelling and relaxation. Consequently, phytoplankton succession in upwelling systems can be partially re-set in a fairly unique way, with intermittent interruptions, returning to earlier stages. Physical features along the coastline, such as capes and embayments, particular topographic features of the slope and continental shelf such as canyons and steep variations in the isobaths, the presence of buoyant freshwater plumes, and the dynamics of oceanic margins, can provide a mechanism for continuously resupplying the biological community during these upwelling/relaxation events; this may explain the seasonal and interannual persistence of HAB assemblages in what are otherwise strongly advective systems. The GEOHAB core research project Harmful Algal Blooms in Upwelling Systems espouses a comparative approach to studying HAB ecology in which multiple, well described natural events within and between regions are compared and contrasted to elucidate common forcing mechanisms as well as regionally distinct influences. We present data focusing on the California Current system, with examples from the Iberian system, that indicate these EBUS regions are becoming more dinoflagellate (red tide) dominated, similar to the Benguela. We suggest that one common feature of these environments is the complex spatial/temporal interweaving of both turbulent and stratified waters, which selects for organisms capable of utilizing both new and regenerated nitrogen, with associated ecophysiological adaptation to the physical regime. Embayments and retentive regions associated with upwelling systems are proposed to provide the ideal combination of nutrient inputs, bloom inocula, and physical retention, leading to persistent bloom hotspots that are functionally identical between EBUS systems. Longer-term changes in HAB dynamics, such as the apparent multi-year increase in red tides in California, may best be understood by comparing the similarities and differences within and among these systems.
3 June, 17:30 (P5 OP6)
Oceanographic conditions affecting the autumn 2005 HAB in north west Iberia M. Cobas-Garcia1, M. Ruiz Villarreal1, P. Otero1, L. Escalera2 and B. Reguera2 1 2
IEO, Centro Oceanográfico de A Coruña, Muelle de Ánimas, A Coruña, 15001, Vigo, Spain. Email:
[email protected] IEO, Centro Oceanográfico de Vigo, Spain.
The north west Iberian region, the northern limit of the Canary upwelling system, is frequently affected by red tides during the autumn transition to downwelling favourable winds. Main oceanographic circulation patterns during this transition (the establishment of a slope poleward current, river plumes, thermal stratification) can help the development of these HABs. Some authors point out that the development of these red tides could be linked with a northward advection from Portuguese waters, related to shelf circulation patterns such as the Inshore Poleward Current established over the inner shelf after the cessation of upwelling conditions, while others think that local populations of dinoflagellates are selected under favourable conditions. This study focuses on oceanographic conditions during the red tide episodes that took place in autumn 2005. During this period, an unusually long presence of Dinophysis acuta and Gymnodinium catenatum dinoflagellates was reported. The last species, carrier of the Parallytic Shellfish Poison (PSP) toxin, had not been detected 159
Eastern Boundary Upwelling Ecosystems Symposium in the area for ten years. The PSP was first detected off the coast of Obidos (Portugal), and 20 days later the toxin was detected 400 km further north. This supports the hypothesis of an along-shore transport. We present a simulation of that period using the Regional Ocean Modelling System (ROMS). The model was forced using wind data from the HIRLAM atmospheric model, and the results were compared with data from oceanographic cruises. Comparison of mean modelled shelf circulation with the chronology of proliferation of toxic cells agrees with the hypothesis of along-shore transport.
3 June, 17:45 (P5 OP7)
Summer diatom and dinoflagellate blooms in Lisbon Bay from 2002 to 2005: preconditions inferred from wind and satellite data P. Oliveira, T. Moita and S. Palma INRB/L-IPIMAR - Sea and Fisheries Research Laboratory, Av. Brasilia, Lisboa, 1449-006, Portugal. Email:
[email protected]
Sea surface temperature (SST) and chlorophyll (Chl) maps derived from satellite data, together with wind time-series, are used to characterise the wind forcing and the spatio-temporal SST/CHL variability for periods of about 10 days preceding the summer (May to September) diatom and dinoflagellate blooms (cells.l-1 > 20,000), identified in the weekly samples collected at the long-term phytoplankton study site in Cascais, from 2002 to 2005. It is shown that bloom detection at the site typically occurs after the relaxation of the upwelling favourable winds, after events of northerly wind speeds greater than 5 m.s-1 for more than 3 days. Satellite maps previous to the events show that surface chlorophyll concentration in Lisbon bay is strongly linked to the ocean circulation resulting from the separation of the coastal upwelling jet at cape Roca, where the coastline orientation changes from a NS to EW direction. This process has a clear SST pattern, characterised by an equatorward extending filament of colder water, and a varying spatial relationship with that of surface chlorophyll in the course of the upwelling event. During intense winds, the higher Chl values are found in the periphery of the filament, mostly along its inshore boundary, inside Lisbon bay, being progressively coincident when the winds slacken and both the cold and the area of high Chl values becomes restricted to the northern part of the embayment. The results suggest that Lisbon bay is a retentive area, playing a key role in bloom development off central Portugal, during the upwelling season.
3 June, 18:00 (P5 OP8)
Dynamics of larval arrival to intertidal habitats in California, Chile and South Africa B. Broitman1, S. Navarrete2, C. Blanchette3, M. Pfaff4, G. Branch4 and S Gaines5 National Center for Ecological Analysis and Synthesis (NCEAS), 735 State St. suite 300, Santa Barbara, 93117, USA. Email:
[email protected] 2 Departamento de Ecología, P. Universidad Catolica de Chile, Chile. 3 Marine Science Institute, University of California, USA. 4 University of Cape Town, South Africa. 5 Department of Ecology, Evolution and Marine Biology, University of California, USA. 1
The dynamics of larval arrival to benthic habitats is a major determinant of the replenishment of these marine populations. Following a long-term program of standardised monitoring of larval recruitment to rocky shore habitats in California, Chile and South Africa we present a spatiotemporal analysis of recruitment dynamics of intertidal mussels and barnacles for each upwelling ecosystem. Results showed that each of the regions examined was divided in north-south sections of contrasting oceanographic regimes: Pt. Conception in California, Pta. Lengua de Vaca in Chile and the Cape Peninsula in South Africa. Regions of low recruitment were characterised by a pattern of sustained upwelling which determined an advective regime that did not promoted larval return to shore. In contrast, regions of high recruitment were characterised by intermittency in upwelling conditions dictated by either topographic sheltering or by basin-scale circulation patterns. The north-south contrasts in recruitment rates were underlined by considerable mesoscale structure within each region. Across regions, the mesoscale patterning determined that the spatial and temporal persistence of recruitment patterns was extremely high and determined by species identity. Our study suggests that regions of high and low recruitment are indeed persistent in space and time and highlights the need of a better understanding of the interaction between larval history and oceanographic conditions for the management and conservation of these coastal ecosystems. 160
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 18:15 (P5 OP9)
Upwelling-driven variation in algal morphology can propagate through the benthic food webs by shifting the balance of positive and negative interactions E. Wieters and S. Navarrete Depto. de Ecología, P. Universidad Católica de Chile, Casilla 114-D, Santiago, La Alameda 340, Santiago, Chile. Email:
[email protected]
Several studies have demonstrated that variation in the intensity of coastal upwelling can be an important regulatory process of benthic communities by altering the input of nutrients and particulate matter, which cascade up the food web via trophic interactions. Much less understood are the non-trophic, communitywide effects that can be produced by variation in upwelling intensity. Here we examine a system conformed by a dominant benthic alga which, depending on the intensity of upwelling, can serve as a facilitator or inhibitor of recruitment of sessile invertebrates as well as habitat for mobile species. Along the wave exposed coast of central Chile, landscape patterns in the height and morphology of turf-forming algae varies greatly among sites in response to differences in onshore nutrient loadings driven by upwelling. Through a combination of laboratory and field studies, we evaluated how such structural changes in algal turfs can have direct and indirect effects in the associated community. At upwelling centers, increased nutrient inputs cause turf algae to grow faster, attain taller heights that suppress mussel colonization, and inhibit crab foraging rates with respect to short turf. At the same time, however, long turf provides crabs with refuge from visual predators (e.g. birds). At warmer, downstream locations with decreased nutrient input, algal turf grows slower, remains short, enhances mussel recruitment and facilitates individual crab foraging rates. But this short turf does not provide protection from birds. In this complex system, the need (and benefits) for refuges during low tides overcomes the reduced predation rates and crabs exhibit strong preferences for the long turf. Increased availability of protective habitat (long turf) strongly benefits local adult crab population size. We examine how these effects propagate through the interaction web. Funds provided by Fondecyt 3060038
3 June, 18:30 (P5 OP10)
Land ahoy! Different onshore transport mechanisms of mussel and barnacle larvae in the southern Benguela upwelling system M. Pfaff1, G. Branch1, J. Largier2 and J. Fisher2 1 2
Zoology Department, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa. Email:
[email protected] University of California, Davis, Bodega Marine Laboratory, USA.
Recruitment dynamics of species with sessile adults and planktonic larvae, which constitute the majority of benthic invertebrates, have long been linked to wind-driven coastal upwelling dynamics. Larvae of near-shore species in particular are thought to be adapted to utilise the landward currents associated with upwelling cycles to be able to complete their life cycles in suitable adult habitats and avoid being lost to sea. Such landward currents exist throughout an upwelling cycle, in the bottom layer during active upwelling and on the surface during relaxation and down-welling. The southern Benguela upwelling system is characterised by seasonal pulses of upwelling-favourable wind, which lead to the recurrence of such upwelling cycles every 2-10 days during austral summer. Additionally, the South African shoreline features major headlands and bays, which are associated with spatial discontinuities of upwelling intensity, forming 'upwelling centres' and 'shadows' respectively. In this highly variable system, our study focuses on the spatial and temporal relationship between upwelling dynamics and larval distribution and settlement of invasive alien mussels and barnacles, which have become the dominant filter-feeders in wave-exposed intertidal communities along the Southern African coast. For a month during upwelling season (Jan-Feb 2007), we sampled the near-shore larval pool daily at 2 sites with contrasting upwelling intensity (Cape Columbine, an upwelling centre, and Elands Bay, a downstream 'shadow'), at 3 distances from shore (0.2 km, 0.7 km, 1.4 km) and in 2 depth strata (top, bottom), as well as coinciding stratified larval settlement (top, mid, bottom) on moorings and along two horizontal zones on the adjacent intertidal rocks. To quantify upwelling dynamics at each site, we concurrently monitored wind speed and direction, current speed and direction (ADCPs) and thermal stratification of the water column. During the study period, we witnessed 4 distinct upwelling events, interspersed with periods of relaxation and one major down-welling event. Near-shore settlement patterns revealed that mussel settlement events coincide with the onset of upwelling, whereas barnacles settle during down-welling. In this presentation, we investigate the specific mechanisms underlying these contrasting larval transport strategies. 161
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 18:45 (P5 OP11)
Coastal mesoscale circulation along central California: consequences for larval transport and management D. Kaplan1, J. Largier2, C. Halle2 and J. Paduan3 IRD, Centre de Recherche Halieutique, av. Jean Monnet, Sète, 34203, France. Email:
[email protected] Bodega Marine Laboratory, University of California Davis, USA. 3 National Park Service, USA. 1 2
Coastal circulation plays a fundamental role in the functioning of coastal ecosystems through its effect on the transport, concentration and dilution of biotic and abiotic materials. In upwelling systems, the study of transport processes is particularly important as it has long been assumed that high offshore and alongshore transport creates a very dispersive environment for larvae of coastal species. In this context, we examine coastal circulation patterns along central California derived from high-frequency (HF) radar measurements of surface currents. Though in general poleward flow is strong over the entire region, there are a number of opportunities for significant retention. There is a significant cross-shore gradient in the strength of upwelling-generated equatorward flow, with consistently weaker flows nearshore. Furthermore, respites in the strength of upwelling-favourable winds, typically occurring on the 2-10 day timescale, produce current reversals in the nearshore. Finally, upwelling strength has long been recognised to be non-uniform spatially, and surface circulation along central California indicates that embayments and wind shadows create zones with reduced alongshore flow where significant retention of materials may occur. The possibility of larval retention in these systems, particularly when combined with active larval behavior enhancing nearshore retention, is good news for a network of marine reserves recently created in the area as marine reserves depend on the local retention of reproductive output. Nevertheless, selection of zones with increased coastal retention may enhance persistence in the marine reserve network, at the possible expense of reducing larval export to non-reserve areas.
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P5 Posters Poster: P5 P1
Influences of the tide on the nesting success of Caretta caretta on the Boa Vista Island (Cape Verde, West Africa) M. Aguilera-Rodà, A. Eiroa, N. Varo, O. López and L.F. López-Jurado Department of Biology, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria 35017, Spain. Email:
[email protected]
In the Cape Verde Archipelago is located one of the most important nesting population of Caretta caretta around the world, mainly at Boa Vista Island. This study has and compared the emergence success of female loggerheads from the sea, based on the tracks, obtained during 2006 and 2007 nesting season. Results show a lower emergence success in 2007 compared to 2006. We attributed this decrease to the fact that during this season tide level has been higher, because of the weather. This circumstance has resulted in decreased nesting areas for this species. This situation warns us about the future of the species in relation to its nesting habitats and coast ecosystems, due to climate change.
Poster: P5 P2
Coastal fish community structure off Ria de Aveiro, W Iberia, in summer 2007: a potential nursery system M. Angélico1, N. Castro1,2, J. Lino Costa2, I. Meneses1, C. Nunes1, A. Silva1, V. Marques1, Y. Stratoudakis1, P. Oliveira1 and I. Domingos2,3 INRB/IPIMAR (Instituto de Investigação das Pesca e do Mar), Avenue Brasília, Lisboa, 1449-006, Portugal. Email:
[email protected] Universidade de Lisboa, Faculdade de Ciências, Instituto de Oceanografia, Portugal. 3 Universidade de Lisboa, Faculdade de Ciências, Departamento de Biologia Animal, Portugal. 1 2
The Iberian Peninsula is located at the eastern boundary of the North Atlantic Ocean, where the N-S orientation of its W coast and the prevailing northerly winds in summer, give rise to a system dominated by upwelling events during the summer months (June to October). For the remainder of the year, other processes such as a slope poleward flow and a buoyant plume, become more relevant in structuring the ocean over the shelf. The coastal region is also subject to a variable degree of mesoscale activity and intermittent, along the shore, currents. The coastal Iberian waters are part of a productive region where several pelagic and demersal species are abundant and targeted for commercial exploitation. In July 2007 a survey was conducted off Ria de Aveiro (NW Portugal) with the objective of studying, during the upwelling season, the area adjacent to the Ria (from the coast up to the 100m isobath) that is a potential nursery for many fish species. The area was characterised for ocean hydrology (CTDF) and near shore currents (ADCP), plankton distribution and composition (oblique Bongo and Neuston tows) and fish community structure and trophic relations (pelagic and bottom trawling) during 2/3 repetitions of a pre-defined sampling grid. This work highlights the results obtained for the fish community analyses: distribution and size composition of the main species and their relation with environmental variables. The most abundant fish species were the pelagic: Sardina pilchardus, Scomber japonicus, Scomber scombrus, Trachurus trachurus, Engraulis encrasicolus and the demersal: Trisopterus luscus, Callionymus lyra, Trigla lucerna, Echiichtys vipera and Pomatoschistus sp. The swimming crab Polybius henslowi was also caught in very high numbers. The area was proven to be significant as nursery for many species namely the commercially important Sardina pilchardus, Trachurus trachurus and Trisopterus luscus. Ontogenic variation with distance from the coast was observed for several species, with smaller (younger) individuals appearing closer to the shore. An ad-hoc fishing haul taken inside the Ria showed the presence of very small juveniles of S. pilchardus. 163
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P5 P3
Influence of the Iberian coastal upwelling and downwelling on the Ria de Vigo, a semienclosed bay E.D. Barton1, R. Torres Almarza2, J. Largier3, M. Sheridan3, A. Trasviña4, A. Souza5 and A. ValleLevinson6 Departamento de Oceanografía, Instituto Investigaciones Marinas, Eduardo Cabello 6, Vigo 36208, Spain. Email:
[email protected] Plymouth Marine Laboratory, United Kingdom. 3 Bodega Marine Laboratory, USA. 4 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Unidad La Paz, Mexico. 5 Proudman Oceanographic Laboratory, United Kingdom. 6 Civil and Coastal Engineering Department, University of Florida, USA. 1 2
The Ria de Vigo is a semi-enclosed bay located near the northern limit of the Iberian upwelling ecosystem. The continental shelf outside the ria is characterised by repeated upwelling events during a short summer period and intermittent downwelling throughout the year. The influence of the upwelling and downwelling events extends well into the ria. Consequently the ria forms part of the largest Mussel production area in Europe. Two intensive field studies involving eight ADCP moorings, rapid MiniBat/ADCP surveys, turbulence observations, airplane overflights and biogeochemical sampling examined the time varying circulation and hydrography during both downwelling and upwelling events. Strong horizontal circulation in the outer ria, related to poleward nearshore flow along the shelf during downwelling, introduced a dramatic warming and a harmful algal bloom in September 2006. In contrast the June 2007 study revealed the dominant influence of the equatorward coastal upwelling jet on circulation in the outer ria and the penetration of a lower layer of cold, nutrient rich water. We examine the changing conditions during these events in the distinctive regimes of inner, central and outer ria. Vertical and horizontal circulations, mixing and their influence on the ecosystem are explored.
Poster: P5 P4
Circulation, water temperature, and larval settlement over the inner Continental Shelf of the Channel Islands, California M. Fewings, L. Washburn, C. Gotchalk, C. Blanchette and J. Caselle Institute for Computational Earth System Science, University of California at Santa Barbara, 6715 Ellison Hall, Santa Barbara, CA, 93106-3060, USA. Email:
[email protected]
We use seven-year-long time series of water velocity, water temperature, salinity and wind stress in 15 m water depth to describe the seasonal patterns of circulation and water temperature over the inner continental shelf of the Channel Islands in the Santa Barbara Basin in California. The Santa Barbara Basin is strongly influenced by the California Current upwelling system. In turn, the water circulation in the Santa Barbara Basin influences the local marine ecosystem by affecting the water temperature and the supply of nutrients and larval fish. The Santa Barbara Channel area of the Basin is also a bio-geographic boundary: it is the northern limit of the ranges of many coastal species that have southern distributions. Larvae, nutrients, and pollutants travelling from the coast to the open ocean must somehow pass through the inner shelf. To date, the water circulation over the inner continental shelf has not been well understood, particularly in the area of the Channel Islands, where the circulation has never before been described. Due to the shallowness of the water, the inner shelf has different physical dynamics than either the surfzone or the middle and outer continental shelf. We discuss the relative importance of upwelling-favourable along-shelf winds and of cross-shelf winds as forcing mechanisms for coastal upwelling circulations over the inner continental shelf; test whether the cross-shelf wind stress and surface gravity waves are important for cross-shelf circulation in the Santa Barbara Basin; and describe the seasonal patterns of water temperature and velocity around the Channel Islands. Cross-shelf circulation and the movement of water masses into and out of the Basin have implications for settlement and recruitment of many coastal species, including the economically important kelp rockfish, kelp bass, and sea urchin. Understanding the circulation of the Santa Barbara Basin and its inner shelves is a precursor to determining the source locations of the planktonic larvae. The information on source locations is essential for the design, citing, and assessment of existing and future marine protected areas in California and elsewhere. 164
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P5 P5
Distribution patterns of macrobenthos community in sandy beaches of Sechura Bay, Piura, Peru K. Ortega1, J. Tarazona2 and A. Indacochea2 International Studies of Aquatic Tropical Ecology (ISATEC), University of Bremen,, Schonhaussenstrasse 32B, Bremen, 28203, Germany. Email:
[email protected] 2 Laboratorio de Ecología Marina, Facultad de Ciencias Biológicas. Universidad Nacional Mayor de San Marcos, Peru. 1
Sechura Bay is located at the convergence zone of cold waters of Humboldt Current system and warm ones of Surface Equatorial Waters. It is an important coastal area due to its high nutrient content and high plankton production. To date, sandy beach studies in Peru have been conducted predominantly in the central coast area. In the north part of Peru, there have been few studies on sandy beaches. Information about macrofauna in Sechura bay is scarce, due to snapshots samplings. The aim of this study was to investigate temporal and spatial distribution patterns of the macrobenthos community in the sandy beaches of Sechura Bay (05° 25’ - 05° 51’ LS, 81° 05’ - 80° 51.3’ LW), Piura, Peru. The sampling was conducted at six sandy beaches during summer and winter 2004. The studied beaches were San Pedro, Chuyillache, Matacaballo, Las Delicias, Vichayo and Bayovar (north to south). At every beach, two transects was performed. Samples were taken every 10 m from drift line to saturation zone, with a metal cylinder of 0.027 m2 and 30 cm depth. All organisms were identified to the lowest possible taxonomic level. Based on density and biomass data, dominance in number and weight per tidal level, for beach and climatic seasons was calculated, to determine variability in dominant species across and along shore of the beaches of Sechura Bay. Average values of density per tidal level and beach were used to describe zonation patterns. A cluster analysis between samples, using Bray - Curtis similarity based on abundance data, was used to determine species assemblages and similarity between beaches respectively. At the dry and retention zone of every beach, the isopod Excirolana braziliensis was the dominant species, whereas at the resurgence and saturation zone, the anomuran crustacean Emerita analoga, or the gastropod Olivella columellaris were dominant. The gastropod Mazatlania fulgurata and the polychaete Capitella sp. were dominant in Las Delicias and in Bayovar during winter respectively. In San Pedro, Chuyillache and Matacaballo, O. columellaris was dominant, reaching the highest density in Chuyillache beach (2080.7/ m2). On the other hand, E. analoga was dominant in Vichayo. In Las delicias and Bayovar ( 5126.6/ m2) this species was dominant during summer. Cluster analysis showed two different communities, one in San Pedro, Chuyillache and Matacaballo and one in Vichayo, Bayovar, Las Delicias. However Las Delicias was dissimilar to the others in winter. These associations can be explained by differences in dominant species between beaches. The macrobenthos communities of sandy beaches along the central coast of Peru are mainly dominated by Donax and Emerita, but in some studied beaches at the north coast of Peru, O. columellaris can be dominant as in Sechura Bay. It was concluded that spatial distribution has more importance than temporal on sandy beach macrobenthos communities at Sechura Bay. O.columellaris distribution and dominance is restricted to the north part of the bay and both dominant species can coexist, but in low densities.
Poster: P5 P6
Subtidal and tidal circulation in the Ría de Ares-Betanzos (Iberian upwelling system) S. Piedracoba1,3, L. Peteiro2, R. Filgueira2, X.A. Álvarez-Salgado2, G. Rosón1, M.J. Fernández Reiriz2 and U. Labarta2 Universidade de Vigo, Facultade de Ciencias do Mar, Marcosende, 36310 Vigo, Spain. Email:
[email protected] CSIC, Instituto de Investigacións Mariñas, Spain. 3 Bodega Marine Laboratory, University of California, Davis, USA. 1 2
Twelve hydrographic surveys were carried out in the Ría de Ares-Betanzos, a coastal embayment in the northern boundary of the Iberian coastal upwelling system where the blue mussel Mytilus galloprovincialis is cultured extensively on hanging ropes. The Ría was visited every 3-4 days during July and October 2007 (six surveys per period). Simultaneously, an ADCP recorded the velocity profile at the central segment of the ría during 24 days in July and 35 days in October-November. In addition, currents were also recorded 165
Eastern Boundary Upwelling Ecosystems Symposium from February to November 2007 in a series of 2D-ACM current meters hung at 1 m and 6 m depth in four mussel rafts located at the northern and southern sides of the Ría. A Fourier analysis was applied to the series of ADCP and 2D-ACM data to separate the tidal and subtidal frequencies at each position and depth. An analysis of the tidal band was performed to parameterise the most significant astronomic components, and study the spatial differences of intensity, direction and tidal phase in order to discuss the synchrony’s differences associated with the geomorphology of the Ría. The subtidal circulation pattern at the surface and bottom layers was studied in July and October-November 2007 from simultaneous current meter and hydrographic data in relation to the remote and local winds, and the continental runoff/tidal prism. The water circulation pattern in the Ría de Ares-Betanzos is a key issue in understanding the spatial differences in larvae settlement and recruitment of Mytilus galloprovincialis.
Poster: P5 P7
Fluorescence quantum yield of DOM in the coastal upwelling system of the Ría de Vigo (NW Spain): a proxy to microbial and photochemical induced changes in the molecular structure of colored DOM C. Romera Castillo1, X.A. Álvarez-Salgado2, C. Marrasé1 and N. Nieto Cid2,3 CSIC, Institut de Ciències del Mar, Passeig Marítim de la Barceloneta, 37-49, 08003 Barcelona, Spain. Email:
[email protected] CSIC, Instituto de Investigaciones Marinas, Spain. 3 Woods Hole Oceanographic Institution, USA. 1 2
The optical properties of dissolved organic matter (DOM) ―absorbance (aDOM), fluorescence (FDOM) and the quantum yield of fluorescence (φDOM)― in a coastal upwelling system depend on i) the composition of the source oceanic and terrestrial waters; and ii) the intensity of the microbial and photochemical processes that occurs during oceanic and continental source waters mixing. A detailed study of the spatial and temporal variability of aDOM, FDOM and φDOM in the coastal upwelling system of the Ría de Vigo, a large coastal embayment of NW Spain, has been conducted under contrasting diatom-dominated summer upwelling and dinoflagellate-dominated autumn downwelling conditions. The variety of hydrographic and biological conditions captured during the sampling program will be used to set the optical properties of the source water types as well as the contrasting effect of the microbial and photochemical degradation processes on φDOM, which is directly related with the molecular structure of the colored DOM. Funds provided by Fondecyt 3060038.
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P7
Phylogenetic, structural and functional diversity of upwelling communities
6 June, 15:15 (P7 KNS)
Linking microbial diversity and ecosystem function in offshore surface waters affected by upwelling waters: a review of approaches, previous work, and focus on the Canary upwelling waters and the central Atlantic Ocean J. Gasol1, L. Alonso-Sáez1, O. Sánchez2, D. Vaqué1 and J. Arístegui3 Institut de Ciències del Mar-CSIC. Barcelona, Catalunya, 08003, Spain. Email:
[email protected] Universitat Autònoma de Barcelona, Spain. 3 Universidad de Las Palmas de Gran Canaria, Spain. 1 2
Linkages between microbial diversity and ecosystem functioning are rarely analysed in oceanic waters. Here, we first analyse the types of approaches that can be used to link microbial biodiversity and ecosystem functioning. We then describe what is known about microbial diversity in offshore upwellings, and then focus on a transect from upwelled waters near the Canary Islands in the NE Atlantic and the open oligotrophic Central Atlantic where we describe the bacterial role in the cycling of carbon. We describe bacterial community structure by means of a fingerprinting PCR-based technique and fluorescent in situ hybridiation, and then link diversity and functioning by using a black box approach (a correlation approach) and a single-cell analysis technique (autoradiography linked to FISH). We discuss whether bacteria can be subdivided into ecologically meaningful boxes for the purpose of modelling the flow of carbon through different bacterial subgroups.
6 June, 15:45 (P7 OP1)
Exploring the consequence of spatial scale on temporal patterns in diversity: using the south coast of South Africa as a case study D. Ghebrehiwet1, J.G. Field1 and R. Leslie2 1 2
University of Cape Town, Marine Biology Research Centre, Cape Town, 7701, South Africa. Email:
[email protected] Marine and Coastal Management, South Africa.
Patterns in diversity and processes affecting observed patterns of fauna and flora of various ecosystems have been the subject of many studies. Some of these studies were conducted to track changes in the ecosystem and to understand the functioning of ecosystems, because of the expected link between diversity and stability/resilience of ecosystems. Despite the interest and effort in biodiversity and its relation to other attributes of ecosystems, there exists unresolved effects of the choice of diversity index and spatial scale at which studies were conducted on the pattern and direction of the relationship. To this end this study explores temporal patterns in diversity when diversity is calculated at different spatial scales. This study is based on data obtained from trawl surveys on the south coast of South Africa. Sampling stations were incrementally aggregated then diversity indices were calculated at each scale and across the time period of sampling. This study gives insight into how tracking temporal changes in the diversity of communities might be affected by the choice of the spatial scale over which the diversity indices are calculated.
6 June, 16:00 (P7 OP2)
Mixed layer and phytoplankton functional diversity: a photobiological approach C. Brunet, C. Dimier, R. Casotti and F. Conversano Stazione Zoologica A. Dohrn, Villa Comunale, Naples, 80121, Italy. Email:
[email protected]
Phytoplankton cells need to acclimate to photon flux density variations that they continuously experience in the upper mixed layer. Among the different acclimative strategies, algae can modify their pigment pool and dissipating excess light energy through non-photochemical quenching (NPQ) of fluorescence. 167
Eastern Boundary Upwelling Ecosystems Symposium Diversity in photoprotective behaviour among algal groups/species has been highlighted, and the different acclimative capacity could correspond to functional traits of species as an adaptation to the ecological niche where they grow. In the present study, we analysed the photoprotective capacities of different microalgae, from different taxonomical groups and those possessing different combinations of light-harvesting complexes and xanthophyll-cycle pigments were compared. The six species are Pelagomonas calceolata (Pelagophyceae), Bolidomonas mediterranea (Bolidophyceae), Phaeocystis cordata and Phaeocystis sp. (Prymnesiophyceae), Mesopedinella arctica (Dictyochophyceae) and Ochromonas sp. (Chrysophyceae). These species all belong to the pico- and nano-phytoplankton and their ecological niches cover the main marine ecosystems, i.e. coastal, upwelling, surface and DCM layers of oceanic systems. Experiments consisted in progressive light increase from 40 to 400 ìmol.photons.m-2.s-1 during which pigments and xanthophyll cycle, quantum yield of fluorescence and NPQ were frequently measured. Gradual light increase corresponds to an ecologically-relevant experimental condition which seems to be well adapted for an ecophysiological interpretation of the data. The observed photoresponses presented a high variability, in terms of activation, kinetics and amplitude in relation with the biological and ecological diversity of the 6 species examined. Photoprotective capacity seems to depend on the ecological niche property where the species grow and to the cellular pigment pool, both factors being interdependent. A complementary study on the growth, photosynthesis and photoacclimation responses of Pelagomonas calceolata to three different frequencies of fluctuating light show that this species is able to well adapt to mixing. However, the biomass production is strongly reduced in the high-fluctuating light regime, maybe in relationship with the enhanced costs for maintenance and repair processes which may have reduced the allocation of energy to photosynthesis. All these observations are discussed in term of adaptation of algae to the ecosystem where they grow, and implications for in situ and modelling studies are presented.
6 June, 16:15 (P7 OP3)
Specific patterns of vertical diel migration of euphausiids in the Humboldt Current. T. Antezana Departamento de Oceanografía, Universidad de Concepción, P.O.Box 4010, Concepción, Chile. Email:
[email protected]
Despite a generalised pattern of up and down migration of the bulk of zooplankton, organisms show distinct behaviors. Evidence of individual species’ patterns of migration and interspecific interactions toward community regulation are scarce and to a great extent missing particularly in upwelling ecosystems. Series of stratified bongo net samples were taken throughout day/night cycle in the Humboldt Current, where severe depletion of oxygen was expected to limit the vertical extent of the zooplankton. The bulk of zooplankton was excluded, but several euphausiids crossed the oxycline and dwelled in the permanent Oxygen Minimun Layer (OML) in daytime. Vertical displacements of populations were followed throughout the diel cycle. The diel migration was characterised by rapid upward displacements, long shallow residences at night, slow downward movements and long deep residences in daytime. Differences were found in the timing and depth of migration: the beginning and duration of the ascent, the timing of the descent, and of the residence in shallow and deep layers and the duration of the ascent. E. tenera migrates continuously, whereas up and down displacements of N. gracilis and S. affine are short to remain in either strata most of the time. E. distinguenda, E. mucronata and E. eximia presented intermediate patterns. Juvenile deviate from their adult pattern, by delaying their down migration and advancing their upward migration. These specific migratory signatures, when associated to their feeding habits suggest that species avoid co-occurrence either in time or in strata in a community trend to share resources or avoid competition.
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P7 Posters Poster: P7 P1
Structural diversity of ostracod assemblages in upwelling regions R. Castillo, P. Ayón and Y. Escudero Instituto del Mar del Peru, Area de Evaluación de Producción Secundaria, Jr. Pedro Torres Malarin 141, Pueblo Libre, Lima, 21, Peru. Email:
[email protected]
High levels of productivity supporting large fisheries occur in the four eastern boundary currents systems and are the result of local forcing and large scale circulation. It has been hypothesised that the observed patterns of zoogeographical distribution in pelagic oceanic environments are determined by patterns of biogeochemical production. Thus, community composition would reflect environmental conditions. Pelagic ostracods, though not very abundant, are ubiquitous and frequent components of the zooplankton. They are commonly regarded as detritivores and they may play an important role in the transport and recycling of organic matter. Though not a rule, there are two patterns that have been found in ostracods assemblage’s analysis: there is a general increase in the carapace size of ostracod species with increasing depth and latitude, and a decrease in species richness with increasing latitude, patterns which might be consistent with a decreasing temperature and physiological constraints. However, comparisons of assemblages with similar levels of productivity and at similar depths and latitudes have not been conducted yet. We hypothesise here that similarities in the specific/ generic compositions may be found between regions of similar environmental conditions reflecting the functional importance of those guilds. Comparisons were conducted using published data for two historical cruises: the Discovery Report Cruise for the Benguela Current in 1950 (Iles, 1953) and the SOND Cruise off Canary Islands in 1965 (Angel, 1969) and compared with data from different cruises off Peru. Patterns of species compositions and diversity of species are explained separately for each region. The oxycline different location is expected to explain differences in the vertical distribution of the assemblages.
Poster: P7 P2
Megabenthic biodiversity in continental margins of two main upwelling areas of West Africa A. Ramos1, F. Ramil2, M. González2, S. Soto2, E. Soto2, E. Balguerías3, E. Hernández3, C. Meiners4, F. Salmerón4, E. García5, C. Burgos5, J.L. Sánz6, O. Tello6, F.J. Cristobo7, A. Faraj8 and H. Mesfoui9 IEO, Centro Oceanográfico Vigo, Punta del Apio, San Miguel de Oia, Spain. Email:
[email protected] Facultad Ciencias del Mar, Universidad Vigo, Spain. 3 IEO, Centro Oceanográfico Canarias, Spain. 4 IEO, Centro Oceanográfico Málaga, Spain. 5 IEO, Centro Oceanográfico Cádiz, Spain. 6 IEO, Centro Oceanográfico Madrid, Spain. 7 IEO, Centro Oceanográfico Gijón, Spain. 8 Institut National de Recherche Halieutique, Morrocco. 10 Institut National de Recherche Halieutique, Centre Régional Laâyoune, Morrocco. 1 2
Starting from the hypothesis that the high productivity in marine areas under the influence of upwellings linked to Canary and Benguela Currents could be reflected in benthic communities of continental margins, data obtained during the joint prospection surveys carried out in deep waters of Morocco, Mauritania and Namibia were analysed. On board O/V “Vizconde de Eza” 586 stations between 400 and 2000 meters depth in the three countries EEZ from 2004 to 2008 were established; during the seven surveys, hauls (one hour trawling real time) were carried out with commercial Lofoten trawl gear, using the swept-area method and following a stratified random sampling procedure; in each station total invertebrate catch were separated to specific level, counted and weighted. Important differences in the composition, distribution and diversity of megabenthos were observed. While in Moroccan deep waters Hexactinellida and Demospongia constituted between 36-46% of total biomass, suspension-feeders seems to disappear south of Cape Boujador, being nearly absent in Sahara, Mauritania and Namibia slopes. Megabenthos is clearly dominated by depositfeeders, particularly Holothuroidea which composed 88% of total biomass in Namibia and up to 92% in Mauritania. Mean biomass was highest in Namibia (414 kg/st), intermediate in Mauritania (160 kg/st), and 169
Eastern Boundary Upwelling Ecosystems Symposium lowest in central and northern Moroccan margin (95 kg/st) and Sahara (68 kg/st), however mean species richness shows decreasing figures from Sahara (36 sp/st), Mauritania (27 sp/st) and Namibia (only 17 sp/st). Possible hypotheses to explain these geographical and bathymetric differences in relation to environmental variables, including geomorphologic and oceanographic characteristics, are discussed in this poster.
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P8
Plankton dynamics, food web struture and ecosystem production
5 June, 15:15 (P8 KNS)
Fuelling the food web from phytoplankton to fish C. Moloney1, C. van der Lingen2, A. Jarre1 and L. Shannon2 Zoology Department and Marine Research Institute, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa. Email:
[email protected] 2 Marine and Coastal Management, South Africa. 1
The southern Benguela upwelling ecosystem exhibits variability on a number of scales. On a local spatial scale and short time scale, upwelling events punctuate the region, fueling large primary production that feeds zooplankton populations. The productivity patches are relatively predictable in time and space, but are not always located where the dominant fish species occur. At times the ecosystem is affected by large-scale environmental anomalies, which may persist for only a few months or for many years. This presentation will examine links from the physical environment, through the phyto- and zooplankton to the vertebrates of the southern Benguela ecosystem. Current understanding of key interactions among food web components will be described. Recent research has elucidated differences in diets of the three main small pelagic species in the region (sardine, anchovy and redeye round herring) and some marked changes in distributions. Possible consequences of variations of diets in time and space will be examined. Processes affecting different life history stages can be important in determining population dynamics and food web structures, and scenarios involving positive and negative feedbacks will be sketched for the southern Benguela pelagic ecosystem.
5 June, 15:45 (P8 OP1)
Primary production in the Benguela ecosystem R. Barlow1, T. Lamont1, B. Mitchell-Innes1, D. Louw2, M. Kyewalyanga3 and H. Sessions1 Marine & Coastal Management, Department of Environmental Affairs & Tourism, Cape Town, South Africa. Email:
[email protected] National Marine Information & Research Centre, Ministry of Fisheries, Namibia. 3 Institute of Marine Sciences, University of Dar-es-Salaam, Zanzibar, Tanzania. 1 2
Investigations of primary production have been conducted at infrequent intervals in the Benguela ecosystem. Studies conducted in 1999, 2002, 2006 and 2007 under the auspices of the regional BENEFIT programme revealed that primary production is highly variable in the Benguela, with some seasonal variability. Standard 14C on-deck, 24-hour bottle incubation experiments were conducted in June-July 1999 (winter) and FebruaryMarch 2002 (summer) between 13oS and 33oS, covering southern Angola, Namibia and the west coast of South Africa. In June-July 1999, primary production was <1 gC m-2 d-1, except for four station where production ranged from 1.50-2.2 gC m-2 d-1, and no significant latitudinal differences were observed. Production was greater in February-March 2002, with values generally between 1 and 2 gC m-2 d-1, but production was <1 gC m-2 d-1 at five stations and 4.5-8.8 gC m-2 d-1 at four stations. Productivity was lower in southern Angolan waters and much more variable off Namibia and South Africa. More modern bio-optical studies of phytoplankton photosynthesis were conducted in the southern Benguela (29oS-34.5oS) in October 2006 and May 2007, utilising 14C photosynthesis-irradiance (P-E) experiments, fast repetition rate fluorometry, phytoplankton absorption and pigments analysed by HPLC. Primary production was estimated from P-E parameters using the exponential model of Platt et al. (1980). Primary production was generally higher during October 2006 (spring), varying from 0.85 to 8.6 g C m-2 d-1, and lower during May 2007 (autumn), varying from 0.7 to 3.3 g C m-2 d-1. Diagnostic pigment indices revealed that communities were mostly dominated by diatoms in October 2006 and mixed populations of small flagellates and diatoms prevailed in May 2007. The variability in primary production could be explained by variations in the photosynthetic parameters of the light reactions of photosynthesis as measured by fast repetition rate fluorometry. An example was at a station in May 2007 where primary production was significantly greater than at two adjacent stations even though the phytoplankton biomass was considerably lower. At this station the values of Fv/Fm and p were both >0.4, indicating a high quantum yield of photochemistry (Fv/Fm) and energy transfer between PSII photosynthetic units (p) in the population, leading to elevated primary production. 171
Eastern Boundary Upwelling Ecosystems Symposium
5 June, 16:00 (P8 OP2)
Copepod biomass and production in the southern Benguela – spatio-temporal patterns, links to pelagic fish and comparisons with other eastern boundary upwelling systems J. Huggett1, H. Verheye1, A. Richardson2,3, L. Hutchings1, T. Fairweather1, P. Ayón4, F. Cazassus1,5, J. Coetzee1, R. Escribano6, S. Hernández-León7, A. Kreiner8, W. Peterson9 and S. Zizah10 Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa. Email:
[email protected] 2 Department of Mathematics, University of Queensland, Australia. 3 Climate Adaptation Flagship, CSIRO Marine and Atmospheric Research. Australia. 4 Instituto del Mar del Peru, Peru. 5 Marine Research (MA-RE) Institute and Zoology Department, University of Cape Town, South Africa. 6 Universidad de Concepción, COPAS Center, Chile. 7 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain. 8 National Marine Information and Research Center, Namibia. 9 Hatfield Marine Science Center, NOAA-Fisheries, USA. 10 Institut National de Recherche Halieutique, Morocco. 1
Zooplankton sampling has been conducted biannually along the west and south coasts of South Africa since 1988, as part of the pelagic fish stock assessment cruises covering the continental shelf (0-200m). This paper presents data on copepod biomass for the region, as well as seasonal (spring and winter) biomass patterns. Abundance maps of key copepod species are also presented, including Calanoides carinatus, Calanus agulhensis, Metridia lucens, Rhincalanus nasutus, Centropages brachiatus, small copepods (Paracalanidae & Clausocalanidae) and Oithonidae. Patterns of copepod abundance are further explored in relation to body size, and whether these have changed over time. Previously established relationships between body mass and growth rate are used to derive copepod production (growth rate x biomass). Trends in copepod biomass and production are examined for different sub-regions around the coast, and potential relationships with temperature, phytoplankton biomass and pelagic fish biomass are explored. Finally, we compare estimates of zooplankton biomass and production from the southern Benguela with estimates from other eastern boundary upwelling systems.
5 June, 16:15 (P8 OP3)
Changes in fish larval community of the northern Benguela upwelling over the last decade induced by changes in the oxygen minimum layer? W. Ekau and S. Bröhl Center for Tropical Marine Ecology, Fahrenheitstr. 6, Bremen, 28359, Germany. Email:
[email protected]
“Regime shifts“ are well documented and include drastic changes from Phytoplankton through to Zooplankton, Benthos and Fish. In upwelling-areas this means, that short food chains are exchanged by longer chained, dinoflagellate based systems with a completely different species composition including sometimes the dominance of jellyfish. It is also likely that in the northern Benguela upwelling area such a regime shift has occurred. Stocks of sardine and anchovy have significantly declined, other species such as horse mackerel, hake and gobies have benefited from this development. From cruises performed during the last ten years it can be observed, that the ichthyoplankton community in the Northern Benguela upwelling area and the Angola-Benguela-front has changed by species composition and abundance. In this contribution, we describe the distribution of fish larvae based on five research cruises into the area. Higher abundances of fish larvae are mostly found in the northerly parts around Cape Frio. General abundance was low, but shifts in species composition could be observed. The amount of sardine and anchovy larvae have decreased to a minimum, other species such as horse mackerel or mesopelagics are dominating the ichthyoplankton. Their vertical and horizontal distribution is closely related to the watermass characteristics. Different tolerance levels against oxygen and temperature predetermine the species' distribution pattern. Multivariate statistical tools are used to separate different fish larvae communities and relate them to environmental parameters and water masses. 172
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5 June, 16:30 (P8 OP4)
Paradox of upwelling ecosystems? L. Postel1 and A. Da Silva2 1 2
Leibniz Institute of Baltic Sea Research, Seesstr. 15, Rostock-Warnemünde, D 18119, Germany. Email:
[email protected] National Institute of Fishery Research, Angola.
Upwelling ecosystems of the trade wind regions are one the most productive marine environments. The highest degree of exploitation is realised in the so called main upwelling sites. Those areas are characterised by favourable bio-productivity throughout the year. One may assume, that food webs in these regions are “bottom up” controlled. However in contrast to areas with a reduced upwelling season, this is probably not the case. The so called “wasp-waist” mode is more likely, as shown by two examples off Mauretania and off Angola / Namibia. The applied methodology was different in both regions and the investigations were performed in different decades, but the results were analogous.
5 June, 16:45 (P8 OP5)
Zooplankton dynamics from 1994 to 2006 in the upwelling systems off Peru and northern Namibia A. Kreiner1 and P. Ayón2 1 2
National Marine Information and Research Center, P.O. Box 912, Swakopmund, Namibia. Email:
[email protected] Instituto del Mar del Peru, Peru.
Zooplankton has been sampled on fixed stations in Peru and Namibia since 1994 and 2000, respectively. In both systems, copepods dominate the zooplankton communities. Copepod abundances on the Walvis Bay monitoring line in Namibia are generally higher than on the monitoring lines off Peru in the northern Humboldt system. In the northern Benguela copepod abundances show a seasonal signal with highest abundances found during the upwelling period (September to November) and lowest abundances during winter (April to August). In the northern Humboldt system lowest average and median abundance values occurred during winter (June and August) and early summer (December). Median abundance values above 10,000 ind. m-3 occurred during late summer (February), in autumn (April) and spring (October). Copepod community structure does not show any clear seasonal signals in the Northern Benguela. A significant change in the copepod abundance and Calanoid copepod community has been observed during 2004/2005 off Walvis Bay (23°S), Namibia. In Peruvian waters a weak El Niño 2002 drastically modified the composition and abundance of copepods, with a clear decrease in the abundance on Acartia tonsa and the increase in the species number of other calanoid copepods. In Namibia the Calanoid copepod communities show significant differences between the inshore, midshelf and offshore regions, with the highest proportion of the herbivorous copepod Calanoides carinatus being found inshore, while the omnivore Metridia lucens dominates the offshore regions. Total abundances are highest on the midshelf and lowest inshore. In Peru we found a clear inshore-offshore gradient with highest abundances occurring at the inshore station (up to more than 20,000 ind. m-3) and lowest abundances at the offshore station (always below 4,000 ind. m-3). Zooplankton dynamics in relation to oceanographic conditions are discussed for both systems.
5 June, 17:30 (P8 OP6)
Zooplankton grazing and secondary production off central Peru during recent El Niño and La Niña events (2006 to 2007) M.I. Criales-Hernandez1, R. Schwamborn2,3, S. Sanchez1, P. Ayón1, H-J. Hirche2 and M. Wolff4 Área de Evaluación Producción Secundaria, Instituto del Mar del Peru, Esquina Gamarra y General Valle s/n Chicuito- Callao, Lima, Peru. Email:
[email protected] 2 Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany. 3 Zoology Department, Universidade Federal de Pernambuco, Recife, Brazil. 4 Dept. Marine Research and Conservation, Charles Darwin Foundation, Puerto Ayora, Galapagos Islands, Ecuador. 1
The marine ecosystems off Peru host the world’s largest single-species fisheries, which is sustained by highly productive pelagic food webs. These systems are subject to strong oscillations and/or state shifts, e.g. from EL Niño (EN, decrease in primary production due to the occurrence of warmer, less nutrient-rich 173
Eastern Boundary Upwelling Ecosystems Symposium waters) to La Niña (LN, low temperatures and strong upwelling). Zooplankton is the main prey for most adult, juvenile, and larval small pelagic fishes in this area. Due to its intermediate position in the food web between phytoplankton and predators, zooplankton serves as a mediator between climate and fish. Therefore, a sustainable fisheries management requires knowledge of zooplankton productivity and the factors that regulate it, e.g. how phytoplankton density and composition influences the grazing activity and productivity of the dominant zooplankters. During 2006 and 2007, several grazing and egg production experiments were conducted in three areas off Callao (coastal area, nearshore shelf, offshore shelf) and in Independencia Bay, central Peru. The objective was to quantify the grazing activity and feeding selectivity of the most abundant zooplankters (the copepods Acartia tonsa and Centropages brachiatus), and egg production rates of A. tonsa. Grazing experiments were conducted in situ, at the depth of peak chlorophyll a fluorescence, where possible. Grazing was measured by cell counts (difference method). A. tonsa significantly fed on diatoms, nanoflagellates, and dinoflagellates. Clearly, bulk ingestion rates were correlated with total phytoplankton densities, increasing from moderate EN conditions (August 2006) towards moderate LN (April/May 2007) conditions. During the moderate EN, nanoflagellates were dominating in the water column and in the diet of A. tonsa, while during moderate LN, diatoms became dominating in the food offered and in the diets. C. brachiatus also followed this pattern, ingesting large amounts of the dominant group (e.g. diatoms). Furthermore, clearance and grazing rates on individual prey species, as calculated by cell counts, showed that A. tonsa and C. brachiatus are highly selective in their feeding (on species level), and may have extremely high clearance rates for individual diatom and dinoflagellate species, even for those that occurred at relatively low densities. Surprisingly, egg production rates of A. tonsa (2.9 to 9.2 eggs per female per day, average: 6.1 +- 2.3 eggs per female per day) were not correlated with total phytoplankton biomass or cell density or with the density of any phytoplankton group. Possibly, the enhanced biomass and ingestion rates (mainly of diatoms) during LN and “neutral” conditions is not converted to productivity and thus not passed directly to upper trophic levels. We discuss how grazing activity, conversion efficiencies, and productivity by copepods have important consequences for the overall ecosystem function within coastal systems through changes in the transfer efficiency to higher trophic levels. Clearly, these processes are crucial for any functional comparison of large Ecosystem Boundary Systems.
5 June, 17:45 (P8 OP7)
Zooplankton size spectra in Peruvian marine ecosystems – preliminary results and perspectives for the comparison between large upwelling ecosystems R. Schwamborn1, M.I. Criales-Hernandez2, P. Ayón2, G. Swartzman3 and H-J. Hirche1 Alfred Wegener Institute for Polar and Marine Research, Am alten Hafen 26, Bremerhaven, 27568, Germany. Email: rschwamborn@ awi-bremerhaven.de 2 Instituto del Mar del Peru, Peru. 3 University of Washington, School of Aquatic and Fisheries Science, Seattle, USA. 1
Size spectra are good descriptors of the structure of aquatic ecosystems and are promising tools for the comparison between ecosystems and ecosystem states (e.g. El Niño/La Niña). However, there are still no comprehensive data on the size structure of the zooplankton in eastern boundary upwelling ecosystems. The shape of a plankton size spectrum is determined by several processes, e.g. by the taxonomic composition (size diversity as a proxy for species diversity), population dynamics of the main species (size structure as a means to assess body growth and changes in abundance) and trophic processes (e.g. relative abundances of preys and predators). Prey size is the key property of the prey field for small pelagics and fish larvae. New equipment and software are now available for the rapid assessment of zooplankton size spectra. Currently, a large volume of recent and historical zooplankton samples at IMARPE are being digitised in the context of the EU-funded cooperative research project CENSOR, thus generating a large database of zooplankton images and size spectra off Peru. Here, we present first results on size spectra generated from zooplankton samples taken in central Peru. These samples were taken with a 200-micron net attached to the multi-sensor PELSS (Particle and Environmental parameter Logging and Sampling System) equipment on the continental shelf and slope off Callao and inside Independencia Bay in 2006 and 2007. We used a modified ZooScan (Biotom) equipment to generate 8-bit grey-scale images at 1200 dpi resolution, and up to 2000 objects per scan. Digital vignettes of each object are being stored, sorted and identified visually for the interpretation of the size spectra and to generate training sets for a future software-based identification. Our preliminary results show that 174
Eastern Boundary Upwelling Ecosystems Symposium there are distinct, characteristic size spectra in these areas. Density always decreased drastically with increasing organism size. Most samples were dominated by small-sized copepods (equivalent spherical diameter from 400 to 1000 µm), such as Acartia tonsa, Paracalanus parvus, Centropages brachiatus, and Hemicyclops sp. At mid-shelf, polychaetes, decapod larvae and amphipods were additionally important in the intermediate part of the spectrum (500 to 2000 µm ESD), and postlarval to juvenile Pleuroncodes monodon were often important in the larger size fraction. Decapod larvae were important in the intermediate part of the spectrum in Independencia Bay. Larger organisms (ESD > 1800µm, e.g. larval, postlarval, juvenile, and adult euphausiids and large copepods such as Calanus sp.) occurred in important densities offshore, thus generating a characteristic second peak in offshore size spectra. The consequences of these results for the distribution of small pelagics are discussed here. Furthermore, perspectives are presented for the use of laboratory and in situ zooplankton sensors for an efficient functional comparison of large eastern boundary upwelling ecosystems.
5 June, 18:00 (P8 OP8)
Environmental forcing of plankton community trajectories in the California coastal upwelling ecosystem M. Landry, R. Goericke and M. Ohman Integrative Oceanography Division, Scripps Institution of Oceanography, Univ. California, San Diego, La Jolla CA, 92093, USA. Email:
[email protected]
CCE-LTER Process studies in the California Current ecosystem focus on the ecological and biogeochemical responses of the California coastal pelagic ecosystem to variable physical forcing affecting stratification and nutrient delivery. Our experimental strategy exploits spatially variable water-column and community characteristics as an analog of conditions associated with climate-related temporal variability of this eastern boundary upwelling system. At contrasting system sites, Lagrangian-designed observational studies follow the daily evolution of community changes in a marked water parcel for 4-6 days as complementary in situ and shipboard experiments elucidate the contributions of different processes and populations to system dynamics and net rates of change. Process studies to date (May 2006, April 2007) show pronounced and coherent system trends in community composition, biomass and size structure, growth rate, production, production:biomass and grazing losses to micro- and mesozooplankton related to physical forcing and nutrient delivery by upwelling. The sums of experimentally measured process rates were also successful in anticipating the directions and magnitudes of net community trajectories in the ambient water column, including major cruise differences in biomass accumulation (2006) versus decline (2007) in upwellinginfluenced coastal waters. The contributions of bottom-up and top-down mechanisms to these varying outcomes are discussed.
5 June, 18:15 (P8 OP9)
A dinoflagellate red tide incubator in an upwelling shadow: the example of Monterey Bay, California J. Ryan1, R. Kudela2, A. Fischer1, P. Bissett3, S. King4, J. Gower4 and F. Chavez1 Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, California, 95039, USA. Email:
[email protected] University of California, USA. 3 Florida Environmental Research Institute, USA. 4 Institute of Ocean Sciences, USA. 1 2
Capes and bays cause significant alongshore variations in the physics, chemistry and biology of eastern boundary upwelling ecosystems. Areas recessed within open bays and in the lee of headlands and capes, known as upwelling shadows, are critical to plankton ecology. Monterey Bay lies in the central California Current upwelling system. The upwelling shadow of northern Monterey Bay is characterised by relatively low wind stress, long residence time, warm stratified surface waters, and high surface chlorophyll concentrations. Recent studies of dinoflagellate red tide blooms in Monterey Bay show that the upwelling shadow functions as a red tide incubator, particularly during Autumn, frequently hosting dense dinoflagellate blooms that can rapidly spread throughout the bay and adjacent waters. Further, retention of red tides within this sheltered environment can persist in the presence of strong mesoscale dynamics that flush the rest of the bay. Using 175
Eastern Boundary Upwelling Ecosystems Symposium six years of satellite and airborne remote sensing observations, we illustrate synoptic and mean patterns of regional blooms. Using five years of multidisciplinary observations from an autonomous underwater vehicle that regularly surveys the bay, we illustrate the physical oceanographic structure and variability of the upwelling shadow. Through process studies that integrate remote sensing with in situ observations from AUV surveys, moorings, and ships, we illustrate physical-biological interactions underlying regional red tide bloom development. These studies examine the processes of bloom initiation, spread, inoculation, dispersion and retention. Observations of Monterey Bay reveal significant influence of the upwelling shadow on regional phytoplankton ecology, and they motivate further study of upwelling shadows as centers of dinoflagellate bloom dynamics in eastern boundary upwelling ecosystems.
5 June, 18:30 (P8 OP10)
Phytoplankton and primary production variability along the NW Africa-Canary Islands coastal transition zone F. Figueiras1, B. Arbones1 and J. Arístegui2 1 2
Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain. Email:
[email protected] Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
The variability in phytoplankton biomass, photosynthetic parameters and primary production (P) was studied along a section extending from the eutrophic upwelled waters at the NW African shelf to the stratified oligotrophic waters west of the Canaries Archipelago. The region was characterised by strong mesoscale variability, with upwelling filaments and island eddies interacting and causing significant vertical displacements of the deep chlorophyll maximum (DCM). According to the hydrographic and nutrient regimes we clustered the stations into three groups. Group I, covering oligotrophic stations both at the open ocean and anticyclonic eddies, was characterised by low values of integrated chlorophyll (33 ± 7 mg Chl m-2) with ~90% of the total phytoplankton carbon biomass due to pico- and nanophytoplankton. Group II, included transitional stations associated with cyclonic eddies and filaments, which showed moderate Chl values (57 ± 16 mg m-2). Group III, covered shelf stations with the highest Chl (112 ± 41 mg m-2) and microphytoplankton contributing > 80% to total phytoplankton carbon biomass. Photosynthetic parameters at the oligotrophic and transitional stations showed similar depth gradients, with highest maximum photosynthetic rates (3.56 ± 0.57 and 4.30 ± 2.76 mg C mg Chla-1 h, respectively) and lowest maximum quantum yields (0.03 ± 0.01 and 0.04 ± 0.01 mol C mol quanta-1) at the surface, and lowest maximum photosynthetic rates (1.51 ± 0.56 and 1.40 ± 0.68 mg C mg Chla-1 h-1) and highest maximum quantum yields at the DCM (0.09 ± 0.03 and 0.08 ± 0.02 mol C mol quanta-1). Shelf waters exhibited maximum photosynthetic rates (3.68 ± 1.67 mg C mg Chla-1 h) similar to surface waters of the other groups, but maximum quantum yields (0.07 ± 0.03 mol C mol quanta-1) comparable to the offshore DCM. P was positively correlated (r2 = 0.82) with phytoplankton biomass. The lowest P (0.39 ± 0.11 g C m-2 d-1) was found at the oligotrophic stations and the highest (2.5 ± 1.1 g C m-2 d-1) at the eutrophic shelf stations, the transitional stations showing intermediate values (0.90 ± 0.28 g C m-2 d-1). Nevertheless, this pattern was significantly modulated by the depth of the photic layer, being negatively (r = -0.70) correlated with P at the oligotrophic stations, but positively (r = 0.47) correlated at the transitional ones.
5 June, 18:45 (P8 OP11)
Coastal waters off Western Australia: an anomalous eastern boundary ecosystem S. Pesant1,2, A. Koslow3,4 and A. Waite2 UPMC Univ Paris 06, UMR 7093, Laboratoire d'Océanographie de Villefranche, 06230 Villefranche-sur-Mer, France; CNRS, UMR 7093, LOV, 06230 Villefranche-sur-Mer, France. Email:
[email protected] 2 School of Environmental Systems Engineering, University of Western Australia, Australia. 3 Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, USA. 4 CSIRO Marine and Atmospheric Research, Australia. 1
Unlike most eastern boundary currents (EBC), the Leeuwin Current (LC) is an anomalous polewardflowing EBC that carries nutrient-poor tropical waters along the coast of Western Australia, thus imposing overall oligotrophic conditions. Interestingly, however, these waters support the region’s (and Australia’s) most valuable single-species fishery, the western rock lobster (Panulirus cygnus). Recent field studies 176
Eastern Boundary Upwelling Ecosystems Symposium addressed this paradox and bring evidence that the overall oligotrophy of the region is regularly offset by localised upwelling. We summarise here this recent body of knowledge including results on the physical oceanography, phyto-, microzoo and meso-zooplankton, and fish larvae. During the austral winter, the strength and the thickness of the LC are greatest, thus limiting primary production by suppressing typical eastern boundary upwelling (EBU) and segregating the underlying nutrient-rich waters from the euphotic zone. However, ocean colour climatologies and field data (2002-2004) reveal that (moderate) peaks of phytoplankton biomass and production in the LC occur in winter. The most popular hypothesis to explain this paradox is that meso-scale eddies are generated by the LC every winter just beyond the shelf break, and may therefore pump nutrients in the euphotic zone of the LC. The eddy kinetic energy of the Leeuwin is greater than that of other EBCs and may be a key feature to support fisheries in this eastern boundary ecosystem (EBE). During the austral summer, the strength of the LC is lowest and coastal winds generate equatorward-flowing countercurrents that also create localised upwelling on the shelf. Field data also show the presence of an ubiquitous Deep Chla Maximum (DCM) in the LC and bring evidence that shoaling of the LC during summer allow the underlying nutrient-rich waters to penetrate the euphotic zone and to fuel Deep Production Maxima (DPM). The significance of these DCMs and DPMs has important implications for the interpretation of ocean colour climatology and derived estimates of production in this EBE. Finally, climatology studies show that the dynamics of the LC is closely coupled with variability in North Pacific circulation, notably the ENSO cycle, because it is driven by a pressure gradient established by the Indonesian Throughflow, i.e. the primary link between the Pacific and Indian Oceans. Time series of the western rock lobster recruitment show positive correlation with the ENSO cycle. These results combined with the growing understanding of localised upwelling should help manage the rock lobster fishery on the coast of WA.
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P8 Posters Poster: P8 P1
Spatio-temporal variation in chlorophyll a, pico- and nanoplankton in the coastal upwelling area off Concepción V. Anabalón, C. Morales, P. González, O. Pizarro, O. Ulloa, R. Escribano, G. Alarcón and A. Varas COPAS, Casilla 44, Dichato, BioBio, VIII, Chile. Email:
[email protected]
The coastal area off central Chile central present a high temporal variability in oceanographic conditions, at different scales of time, including seasonal coastal upwelling. In turn, the foci of upwelling are associated with bottom topography and coastline, providing high spatial variability in the oceanographic conditions within the coastal band. The impact of these sources of variation over the structure of planktonic communities has been recently analysed in a systematic way for the seasonal and interannual scales at a fixed station (COPAS time series, St.18); at the spatial scale, however, studies of planktonic communities are scarce and have emphasised the micro-planktonic component. In this study, the spatio-temporal variation in the distribution and abundance of the pico- and nano-plankton, together with phytoplankton (total and fractionated) biomass, were analysed for an area over the continental platform off Concepción (~36ºS) during three cruises in the austral spring of 2004, 2005 and 2006. Also, the spatial variability during these cruises was compared with that from St.18 during the same period (austral spring) and the association of the variation in oceanographic conditions with the variation in the planktonic components was analysed. Conditions typical of upwelling were present during the cruises, with lower surface temperature (T) values and higher surface salinity (S) in the coastal band; similar conditions were detected in the fixed station. Surface chlorophyll a (Chl a) in the total ranged between 0.03 and 21.8 mg m-3, the fraction <20 µm being a dominant component in the water column (mean of 48 to 77%). Surface values at St.18 were in the same range (0.07 a 23.3 mg m-3), the fraction <20 µm providing 38 to 48% of the total in the water column. In the interannual comparison (ANOVA non-parametric), significant differences were found in the surface layer (0-35 m) for T, NO2, Si, hetrotrophic nanoflagellates (HNF), cianobacteria (CYA), picoeukarionts (EUK) and heterotrophic bacterioplankton (BAC). S, O2, NO3, Chl a total and fractionated, and autotrophic nanoflagellates (ANF) were similar, even though the dispersion in the values of the biological variables was wide. In the subsurface layer (50-100 m), differences in O2, PO4, Chl a <3 µm, NO2, Si, CYA, EUK, and BAC were found. Cruise stations more close to St. 18 were significantly different from the latter in terms of N02, Si, Chl a total and <3 µm, and picoautotrophs (PA) in the surface layer whereas T,S, O2, NO3, PO4, BAC, ANF and HNF were similar. At the subsurface layer, significant differences in O2, chl- total and <20 µm, BAC and ANF were found. Altogether, the differences between cruises are explained by different levels of upwelling activity; the similarity between the stations closer to St.18 reveals that the latter, for the most part, represents the general conditions found over the platform, in particular over the Itata terrace, during the upwelling period.
Poster: P8 P2
Coastal upwelling systems as equatorwards extensions of distribution range for high-latitude pelagic species: a case study on the amphipod T. gaudichaudi in the Benguela Current H. Auel1 and W. Ekau2 1 2
Marine Zoology, University of Bremen, P.O. Box 330 440, D-28334 Bremen, D-28334, Germany. Email:
[email protected] Centre for Tropical Marine Ecology, University of Bremen, Germany.
The cold and highly productive waters of coastal upwelling areas provide habitats for marine species usually occurring at higher latitudes and allow those species to extend their distribution ranges towards the equator into regions otherwise characterised by warm and oligotrophic subtropical waters. Especially the very active coastal upwelling systems of the Humboldt Current and Benguela Current represent northward extensions of the distribution ranges of Antarctic or Southern Ocean species. Focussing on the pelagic hyperiid amphipod Themisto gaudichaudi as a case study, this presentation addresses the distribution patterns, life-cycle adaptations and trophic roles of high-latitude species in coastal upwelling regions and on the abiotic and/or biotic environmental factors actually limiting their distribution ranges. The amphipod T. gaudichaudi is a very important component of meso- and macrozooplankton communities in the Southern Ocean and represents a trophic link from mesozooplankton secondary production to higher trophic levels including many seabirds 178
Eastern Boundary Upwelling Ecosystems Symposium and marine mammals. Field studies on the regional and vertical distribution of T. gaudichaudi in the northern Benguela upwelling region in relation to hydrographic conditions (SST) during research cruises in 2004, 2007 and another cruise schedulded for early 2008 will be combined with ecophysiological measurements of respiration rates and biochemical analyses of trophic biomarkers (stable isotopes delta15N, delta13C and fatty acids) to describe the ecological niche, trophic position and metabolic activity of T. gaudichaudi at its northern most distribution limit. For the interpretation of the results, comparative data of other Themisto species from polar, boreal and temperate regions will be used. In the Benguela upwelling region, T. gaudichaudi reaches its northern distribution limit at approximately 23°S. Compared to congeners from higher latitudes, the relatively higher water temperatures in the coastal upwelling region lead to higher respiration rates, higher food requirements, faster growth, potentially earlier sexual maturity and smaller body size. Due to the high intra- and inter-annual variability of upwelling intensity, time-series data of several years are necessary to address this topic appropriately.
Poster: P8 P3
Acoustic study of the spatiotemporal distribution of zooplankton biomass off Peru provides new insights into Humboldt Current system productivity M. Ballón Soto1, A. Lebourges-Dhaussy2, M. Gutierrez3, S. Peraltilla4 and A. Bertrand1 ECO –UP – IRD, UR-097, Teruel 375, Miraflores, Lima, Lima-18, Peru. Email:
[email protected] IRD, Brest, France. 3 Tecnologica de Alimentos (TASA), Peru. 4 Instituto del Mar del Peru, Peru. 1 2
The Humboldt Current system (HCS) is the most productive region in the world in terms of fish, mainly anchovy. Primary production of the HCS is not thought to be substantially higher than that of other upwelling systems. However, this primary production supports a high enough zooplankton production (mainly euphausiids and copepods) to feed the tremendous anchovy population. Until now, information on zooplankton, came from net sampling (mainly information on biovolume), which provides data discrete in space and time and biased owing to the net selectivity. Although the zooplankton production is required for validating biogeochimical models, adjusting trophic models and more generally to understand ecosystem functioning, no reliable estimation of zooplankton biomass is available at a high spatial resolution in both the horizontal and vertical plan. However, information on zooplankton is available (albeit cryptic) from most of routine acoustic surveys; it is the case for pelagic acoustic surveys performed by IMARPE along the Peruvian coast. We developed a method to extract the zooplankton scatter field (mainly fluid-like organisms, e.g. euphausiids and copepods) and estimate zooplankton biomass from IMARPE acoustic bi-frequency data (38 and 120 kHz) for the summer and winter pelagic surveys of the years 2005 and 2006. This work reveals the first large-range acoustic estimation of zooplankton biomass and distribution in the HCS. Horizontal and vertical patterns of the zooplankton biomass distribution are described. In particular, the main patterns of zooplankton patchiness (sub-meso and meso-scale features), which are indicators of both physical forcing (e.g. eddies) and forage fish cluster size, are described. Results are discussed according to current knowledge of HCS and other eastern boundary upwelling systems EBUS function.
Poster: P8 P4
Seasonal versus mesoscale variability in the abundance, distribution and trophic structure of nano- and picoplankton communities along the NW Africa- Canary Islands transition zone F. Baltar1, J. Arístegui1, M. Montero1, M. Espino1, M. García-Muñoz1, J. Gasol2 and G. Herndl3 Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Spain. Email:
[email protected] 2 Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar – CSIC, Spain. 3 Department of Biological Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), The Netherlands. 1
We have studied the variability of picoplankton and nanoplankton autotrophic (A) and heterotrophic (H) communities along a zonal gradient extending from the NW African shelf up to 500 Km offshore, during two contrasting seasonal periods: late winter and summer. Plankton background abundances differed 179
Eastern Boundary Upwelling Ecosystems Symposium significantly between the two periods, with higher picoplankton cell abundances during summer time. In particular, heterotrophic bacteria (HB) and Prochlorococcus were an order of magnitude more abundant in summer, presumably due to a higher loading of dissolved organic matter and higher temperatures, respectively. Variability in the ratio of A to H biomasses was also evident, with a lower average ratio during summer. Over the African shelf, picoplankton presented the lowest concentrations during summer, while both the autotrophic and heterotrophic nanoflagellates showed the highest abundances. On the contrary, in late winter, the highest concentrations of picoeukaryotes (PE) and Synechococcus (Syn) were found over or close to the shelf. The offshore sampling sections intersected a complex area of strong mesoscale variability, with the presence of upwelling filaments and cyclonic and anticyclonic eddies, which affected the plankton distribution and abundances. In summer, the entrainment of an upwelling filament around a cyclonic eddy provoked the accumulation of dissolved organic matter and the increase of HB and Syn abundances in about an order of magnitude with respect to the surrounding waters. On the other hand, PE were more abundant over the core of cyclonic eddies, where nutrient pumping was evident. In late winter, downwelling of water was apparent at the sharp front between an upwelling filament and an offshore eddy, sinking all planktonic groups down to 150-200 m. In summary, our results indicate that, although seasonality affects the background variability in small plankton communities, the recurrent mesoscale variability found in the Canary Islands transition zone strongly modulates the patterns of distribution, abundances and changes in community structure observed in the region.
Poster: P8 P5
New results on Euphausia hanseni as a component of the upwelling systems of the Namibian-Angolan shelf under conditions of climatic change F. Buchholz Alfred Wegener Institute for Polar and Marine Research - BAH, 27498 Helgoland, Germany. Email:
[email protected]
Extensive studies on the ecology of the Benguela/Angola upwelling system have addressed euphausiids as a central component of the zooplankton communities. “Krill” in this area comprises at least 8 species with a potential to dominate the plankton at up to 60% of its biomass. Accordingly, they hold an important position in the neritic and the pelagic food webs. Euphausiids have also served as indicators of water masses and their horizontal and sometimes their vertical distributions have therefore been recorded. Euphausia hanseni is the largest and most widely distributed krill species and is a crucial food source for (commercial) fish species, one of them pilchard, Trachurus spec. Until now the relatively large E. hanseni has obviously been underestimated, since the employed nets were too small. Large individuals are prone to avoid small nets. E. hanseni is omnivorous and seems to play a crucial, so far underestimated role in the ecosystems. The correspondingly short food chain (phyto-/zooplankton-krill-fish) and its potential for amplification concerning qualitative as well as quantitative changes can therefore be very well assessed in modelling approaches, particularly under climatic aspects. Still missing are detailed studies on growth, reproduction, and energy metabolism particularly in relation to oxygen depletion and temperature tolerance. It is necessary to investigate the effects of those factors parallel to dependencies on the trophic regime, since euphausiids are pronounced vertical migrators and have to cope with steep gradients of oxygen and temperature on a diurnal scale. Respiration studies are supported by determinations of aerobic and anaerobic key enzymes and their potential for adaptation. Comparisons with krill species from temperate and polar zones are expected to be helpful also under climatic conditions. In krill, ovarian maturation cycles and moulting cycles are closely coupled. Both cycles are further controlled by external factors that, according to recent investigations, can be related to food pulses like phytoplankton blooms. First results on Euphausia hanseni indicate a far-reaching synchronisation of the cycles with a dependency on upwelling events. This particularly close coordination of growth and reproductive processes can be interpreted as a specific adaptation to the strongly pulsed upwelling 180
Eastern Boundary Upwelling Ecosystems Symposium regime. How this coordination depends on the prevailing trophic situation is being investigated under overarching food web aspects (see also contributions Auel, Ekau, Hagen).
Poster: P8 P6
Accumulation of northern krill (Meganyctiphanes norvegica) in a converge zone at the southern Bay of Biscay. J. Cabal Naves1, E. Nogueira1, J. Miquel Batle2, G. González-Nuevo1, R. Revilla1, E. Álvarez1 and J. Bueno1 1 2
IEO, Centro Oceanográfico de Gijón, Avda. Príncipe de Asturias 70 bis, Gijón, Asturias, 33212, Spain. Email:
[email protected] IEO, Centro Oceanográfico de Baleares, Islas naleares, Spain.
Physical-biological interactions generate spatial patterns in the distribution of plankton. In the last decade, it has being emphasised the importance of mesoscale physical structures in the distribution and production of plankton. Some authors have shown that organisms at the higher-trophic levels, including cephalopods, cetaceans and sea-birds also respond to these mesoscale features that control the availability of their prey. Northern krill (Meganyctiphanes norvegica) plays a pivotal role in the transfer of energy from the lower to the higher trophic levels of the food-web. The general oceanographic conditions during the cruise revealed the occurrence of coastal upwelling in the Cantabrian Sea in autumn. During this cruise, a thin and large layer (ca. 15 m height on average and 1 nautical mile in length) of northern krill was acoustically detected, and confirmed by a fishing haul, at the sub-surface layer (between 15-30 m depth) over the shelfedge at the cap Breton Canyon. The position of this layer is concurrent with a converge zone associated to anticyclone eddy activity in this area. As far as we know, this is the first time that such a large layer of northern krill is reported in the Bay of Biscay.
Poster: P8 P7
Zooplankton during El Niño-type events in eastern boundary current systems F. Cazassus1, P. Ayón2, R. Escribano3, J. Huggett4, A. Kreiner5, H. Verheye4 and S. Zizah6 Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa. Email:
[email protected] 2 Instituto del Mar del Peru, Peru. 3 Departamento de Oceanografía, Universidad de Concepción, Chile. 4 Marine and coastal Management, South Africa. 5 National Marine Information and Research Center, Namibia. 6 Institut National de Recherche Halieutique, Morocco. 1
El Niño events are a characteristic feature of the Humboldt Current system off Peru and Chile that affect the whole foodweb and are a major contributor to interannual variability. In recent years, a major event took place during 1997-1998. A similar warming event, called Benguela Niño, has been described in the Benguela Current system off southern Africa. Being less predictable, it does not follow any cyclic pattern, and its impact on the ecology of the system appears less dramatic. The 1995 Benguela Niño was the strongest warming event recorded in the region. Zooplankton communities, at the lower levels of the trophic system, are sensitive to environmental changes. During an El Niño-type event, the structure of the community and its species composition change to that of a warm oceanic or equatorial water type community that is usually transitory and reverts back to its original state once the event has ceased. The same cannot be said of the zooplankton of the northern Benguela during the 1984 Benguela Niño, when the community did not return to its previous state but established a new one. In this paper we examine the variations in the community structure of the southern Benguela before, during and after the 1995 Benguela-Niño and compare these with observations related to the 19971998 El Niño in the Humboldt system. The likelihood of such an event occurring in the Canary Current system based on recent observations in zooplankton off Morocco is briefly discussed. 181
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Poster: P8 P8
Phytoplankton dynamics related to cyclonic eddies in the South China Sea J. Chen, B. Huang, X. Liu, L. Lin, L. Wang and S. Xu State Key Laboratory of Marine Environmental Science, Environmental Science Research Center, Xiamen University, Xiamen, 361005, P.R. China. Email:
[email protected]
Phytoplankton community structure related to several cyclonic eddies in the South China Sea (SCS) were investigated in winter (2006) and summer (2007) using photosynthetic pigment analysis by highperformance liquid chromatography (HPLC), BBE fluoroprobe. Several cyclonic (cold) eddies occurred in the different time and different regions displayed variations of phytoplankton distribution. Two cold eddies (named CE I and CE II here) were observed in summer. Maximum chlorophyll a layer was lifted up with the corresponding extrusion of thermocline, leading to higher chlorophyll a in the upper layer of water column. However, for water column, it was not evident that phytoplankton growth was promoted by cold eddies. For CE I, averaged integrated chlorophyll was 0.212 mg/m3, phytoplankton grew up in central region compared to outside. By contrast, for CE II, phytoplankton biomass in the water column was much lower in the central region (0.122±0.028 mg/m3) than the edges (0.196±0.048 mg/m3). Similar phytoplankton structure variation was found in two cold eddies. In time series station TS1 (Central CE I), phytoplankton community structure kept stable, although significant diurnal variation of chlorophyll a was observed, of which, diatoms were well promoted. While in Cold Eddy II (CE II), prasinophyceae, haptophytes and cryptophytes were promoted in the central region, while diatoms, haptophytes and cyanobacteria were promoted on the edge of CE II. The differences in phytoplankton among cyclonic eddies were mostly related to the age of eddies and origin waters.
Poster: P8 P9
Zooplankton seasonal variation at an upwelling shadow coastal station off Western Iberia: relation to environmental conditions J. Cruz, A. dos Santos, J. Pastor and A. Miguel Santos INRB-IPIMAR, Av. Brasília s/n, 1449-006 Lisboa, Portugal. Email:
[email protected]
The Western coast of the Iberian Peninsula represents the northern limit of the eastern North Atlantic Upwelling System and is considered an important transition zone. Investigation on zooplankton communities along the Portuguese coast is still limited to occasional studies, lacking long-term information able to determine zooplankton seasonal and interannual changes in relation to environmental conditions. Since February 2005, zooplankton biomass, abundance, composition and diversity have been studied monthly at a coastal station off Cascais, Portugal. Sampling consists of an oblique tow using a WP-2 net and a superficial tow made with a Neuston net. Environmental parameters such as temperature, chlorophyll a, upwelling index and precipitation were also obtained. Zooplankton biomass did not show a clear seasonal pattern. However, the highest values occured in early spring or summer/autumn and the lowest in winter. Moreover, interannual variation in zooplankton biomass with lowest values during 2006 compared with the other years was observed. Copepods dominated the zooplankton community reflecting the seasonal pattern of the total zooplankton, with Acartia, Paracalanus and Clausocalanus being the most abundant genera, followed by Oithona, Oncaea, Temora and Centropages. Other abundant groups were the appendicularians (Oikopleura and Fritilaria) and cladocerans (Podon, Evadne and Penilia), the former occurring throughout the year with no clear pattern and the latter occurring particularly during warmer months. In general, zooplankton diversity is negatively correlated with biomass and abundance indicating that zooplankton peaks are explained by a relatively low number of taxa. A principal component analysis (PCA) applied to the environmental parameters revealed that the major variability can be explained by the first two components. Principal component 1 was correlated with upwelling and precipitation while principal component 2 was correlated with chlorophyll a and temperature. Temora stylifera seems to be associated with upwelling and precipitation conditions and cladocerans, siphonophores and chaetognaths with temperature. 182
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Poster: P8 P10
Food conditions of an important pelagic fish species north and south of the Angolan Benguela Frontal Region A. Da Silva1, B. Axelsen2 and L. Postel3 National Institute of Fishery Research, Rua Mortala Mohamed, Luanda, 2601, Angola. Email:
[email protected] Institute of Marine Research, Bergen, Norway. 3 Leibniz Institute of Baltic Sea Research, Rostock-Warnemünde, Germany. 1 2
Horse mackerel (Trachurus spp.) is the most abundant genus of commercially important pelagic fishes in Angolan waters and is very popular on the markets. Its percentage was larger south of the Angola Benguela Frontal Zone than north of it. Zooplankton larger than 0.2 mm is its predominant food source. We investigated whether food requirements and food supply were in balance or not. For this purpose, we calculated the concerning zooplankton P/B ratio based on the actual average individual mass and determined the volume specific daily zooplankton production rate at first. Then, we determined the corresponding consumption rate by horse mackerel, based on acoustic abundance measurements, individual body mass determinations and the likely daily food requirements taken from the literature. Sampling was done nearly synchronously in July / August 2000 on the Norwegian r/v “Dr. Fridjoff. Nansen” and in August / September 2000 on the German r/v “Meteor” in the near coastal zone of 20 to 500 m water depth between 8°S and 17°S. In all the regions, we found suitable food conditions for horse mackerel. However, south of the Angola Benguela Frontal Zone – in the region dominated by near coastal upwelling – the situation shifted to the worse, because of a higher concentration of smaller fishes, which have a larger individual specific food demand per day. There was a tendency of “top down controlled” zooplankton standing stock, which seems to be a paradox in one of the most productive marine ecosystems.
Poster: P8 P11
Reproductive strategy of Cape horse mackerel Trachurus trachurus capensis inferred from ichthyoplankton data collected in the southern Benguela upwelling system, 2000–2005 M. Dopolo1 and C. van der Lingen1,2 Marine and Coastal Management, Department of Environmental, Affairs and Tourism, Private Bag X2, Rogge Bay, 8012, South Africa. Email:
[email protected] 2 Marine Biology Research Institute, Zoology Department, University of Cape Town, South Africa. 1
The reproductive strategy of Cape horse mackerel (Trachurus trachurus capensis) in the Southern Benguela is not well documented, and the time and location of spawning by this species has primarily been derived from analysis of gonadosomatic data. These analyses have indicated that Cape horse mackerel show two spawning peaks, the timing of which differs for fish on the southwest and southeast coasts, and have also suggested the possibility of a south-westerly spawning migration by fish on the south coast during summer. We assessed the reproductive strategy of Cape horse mackerel by analysing ichthyoplankton samples collected with a continuous, underway fish egg sampler (CUFES) during surveys along the South African coastline conducted in both summer (November) and winter (May) over the period 2000-2005. In addition, we also analysed samples collected off the southwest coast using a closing WP 2 net. We present horizontal egg distribution maps derived from CUFES samples for each of the surveys and egg vertical distribution profiles derived from WP 2 samples, and briefly discuss the implications of our findings regarding Cape horse mackerel reproductive strategy.
Poster: P8 P12
Metazooplankton variability at the coastal upwelling zone off Central Chile (36°S) in the eastern boundary Humboldt Current C. Pérez1, R. Escribano1,2 , K. Donoso1 and K. Manríquez2 1 2
COPAS Center, Universidad de Concepción, Chile, P.O. Box 160 C, Concepción, Chile. Email:
[email protected] Department of Oceanography, Universidad de Concepción, Chile.
Interannual and seasonal variation of mesozooplankton was studied in the upwelling and offshore zones off Central Chile from a monthly time series study at Station 18 (2002-2007), and spring spatial surveys (2004, 2005 and 2006) from nearshore to 200 nm offshore. Zooplankton biomass (mg C m-2) and dominant species were assessed in the upper 200 m using a1 m2 Tucker Trawl net along with hydrographic data. 183
Eastern Boundary Upwelling Ecosystems Symposium Zooplankton C remained high throughout the year (> 12 mg m-3) at Station 18 with non-significant seasonal changes, but with significant interannual variation and a negative trend from 2002 to 2007. Over the spatial scale there were also remarkable changes in biomass distribution from year- to- year. The zooplankton community is dominated numerically and in biomass by calanoid copepods and euphausiids. Dominant species exhibited strong correlations to each other and also showed substantial interannual variation at Station 18. The dominant copepod species were Acartia spp., Paracalanus cf. indicus, Calanus chilensis, Centropages brachiatus and Rhincalanus nasutus. These species showed consistent annual cycles associated with a strongly seasonal upwelling regime. Our findings suggest that zooplankton responses, in terms of biomass, numerical abundance and community structure, to changing upwelling regimes may act as a key indicator for ecosystem state upon ongoing climate change.
Poster: P8 P13
Vertical distribution and migration of a zooplankton community off Callao in the Humboldt Current in 1996 and 1997 Y. Escudero, R.Castillo and P. Ayón Área de Evaluación de Producción Secundaria, Dirección de Investigación en Oceanografía, IMARPE, Jr. Simón Bolívar 139 Dpto. 404, San Miguel - Lima, Lima 32, Peru. Email:
[email protected],
The Humboldt Current system extends along the west coast of South America and is considered the most productive marine ecosystem in the world. Upwelling along the Peruvian coast occurs all year round, characterising its waters with low temperature, moderate salinity, an oxygen minimum and high levels of nutrients. Vertical distribution of zooplankton responds to environmental factors (abiotic variables, but also prey availability and predator presence). Therefore, differences not only at the composition of species, but also in terms of behavioral response are expected to occur in the zooplankton communities when normal upwelling conditions are altered due to the presence of El Niño events. This study shows the results of the analysis of the vertical distribution and diel vertical migration of a zooplankton community in a fixed station off Callao, considered as one of the zones with highest upwelling intensity in the Humboldt Current. Samples were taken at four depth strata with a closing net (200 µm mesh) in vertical hauls every two hours during three consecutive days in June 1996 (cold year conditions) and June 1997 (an El Niño Event). The results show that zooplankton was dominated by copepods, among which Paracalanus parvus, Acartia tonsa and Centropages brachiatus contributed 93% of total zooplankton in 1996 while during 1997, Paracalanus parvus, Calanus australis and Clausocalanus sp. contributed up to 65%. Some organisms of the zooplankton community seem to be limited by the thermocline and oxycline, showing a deepening of their distribution during El Niño Event. At all sampling times for both years, the weighted mean depth abundance of organisms was limited to the layer between the surface and the 40 m; however, variations in the patterns of vertical migration of copepods were observed between the two years.
Poster: P8 P14
Seasonal variability in microbial autotrophic and heterotrophic plankton biomass in the northwestern Iberian shelf O. Espinoza, B. Crespo, I. Teixeira and F. Figueiras Instituto de Investigaciones Marinas, Eduardo Cabello 6, 36208, Vigo, Spain. Email:
[email protected]
Biomass of autotrophic and heterotrophic plankton (<200 µm) in the NW Iberian shelf waters were determined from a weekly sampling between May 2001 and April 2002. The hydrographic and nutrient regimes revealed that sampling began during a stratified period, which was followed by an upwelling-downwelling cycle at the end of summer-beginning of autumn. Later, in winter, the Iberian Poleward Current (IPC), a northward stream of subtropical oceanic water that regularly establishes in the region during this season, was observed. Sampling ended with the beginning of the spring bloom. Stratified and upwelled waters showed similar total plankton carbon biomass (9.4 ± 0.7 and 9.8 ± 1.9 gC m-2) but differed in trophic status and plankton composition. While in stratification the system was heterotrophic (hetrotrophic:autotrophic ratio H:A = 1.56) and nanoplankton dominated the autotrophic biomass (80%), under upwelling the system shifted to autotrophy (H:A = 0.51) with lower importance of autotrophic nanoplankton (50%) and a significant 184
Eastern Boundary Upwelling Ecosystems Symposium contribution of diatoms (40%). Nanoplankton (60%) and bacteria (20%) were the major contributors to the heterotrophic biomass in both cases. During autumn downwelling total plankton biomass decreased (5.6 ± 0.4 gC m-2), nanoplankton and Synechococcus accounted for ~80 and 16% of the total autotrophic biomass, respectively, and the system came back to be heterotrophic (H:A = 1.13). Again, nanoplankton (70%) and bacteria (20%) were the most important heterotrophic components. This tendency towards low plankton biomass, dominance of pico- and nanoplankton within autotrophs and high heterotrophy extended to the IPC season, when total plankton biomass was 4.4 ± 1.2 gC m-2 and H:A = 1.42. The system returned to be autotrophic (H:A = 0.78) in spring, when total plankton biomass reached values of 8.5 ± 2.3 gC m-2. Although nanoplankton accounted for 77% of autotrophic biomass, diatoms began to be important (13%). Nanoplankton and bacteria continued representing ~70 and 20% of the heterotrophic biomass, respectively. Over the annual cycle the systems were almost in balance or slightly heterotrophic, with heterotrophic and autotrophic biomass representing 54 ± 14 and 46 ± 12% of the total plankton biomass, respectively. From these data, it can be inferred that under hypothetical weaker upwelling, owing to climate change, stratification and heterotrophy would prevail in this upwelling region.
Poster: P8 P15
Analysing spawning habitats of Sardina Pilchardus in the Atlantic Moroccon coast (21°N-26°N) O. Ettahiri1, Am. Berraho1, A. Ramzi1, R. Houssa1, A. Orbi1 and E. Machu1,2 1 2
Institut National de Recherche Halieutique, 2 Rue Tiznit, Casablanca, Morocco. Email:
[email protected] IRD, France.
The spatial and temporal characteristics of the spawning-grounds and nurseries of the Moroccan sardine in the south Atlantic coast (21°N-26°N) were analysed in relation with the hydrology of the zone. The data used in this work concern the 1994-1999 and 2001-2004 periods. The eggs and larvae distribution were dependent on the spawning place in a first time, followed by the hydrological conditions that influences the distribution of the ichtyoplancton. So the variation in the oceanographic environment on a yearly time scale can cause some internal changes on the distribution of the adult fish, as well as on the products of spawning. This study showed that the main spawning-ground of the sardine is located between Dakhla (24°N) and south of Boujdor (25°N), whereas the main nursery is located, more to the south, between the Cintra Bay (23°N) and Dakhla (24°N) with a certain overlap toward the Dakhla region. The positioning of the “centroides” of eggs and larvae abundance allowd a distinction between zones of spawning-grounds and main nurseries to be made and shows an influence of the physical factors.
Poster: P8 P16
Phytoplankton community composition, DMSP-lyase and dimethylsulphide (DMS) in the Mauritanian upwelling in June 2006 D. Franklin1, A. Poulton2, J. Young2, M. Steinke1 and G. Malin1 1 2
University of East Anglia, Sch. Environmental Sciences, Norwich, Norfolk, NR4 7TJ, United Kingdom. Email:
[email protected] Natural History Museum, United Kingdom.
We assessed the concentration of the trace gas dimethylsulphide (DMS) and the composition of phytoplankton in the Mauritanian upwelling system in June 2006 in order to investigate the relationship between phytoplankton species composition and DMS. As well as DMS, accompanying measurements of DMSPparticulate, DMSPdissolved, DMSP-lyase (DLA) activity, and photosynthetic pigments were collected. At offshore well-stratified stations, Chl a concentrations were low (maximum of <500 ng l-1) with phytoplankton biomass dominated by coccolithophores such as Umbilicosphaera sibogae and Umbellosphaera tenuis (up to 0.5 mg C m3) as well as dinoflagellates (up to 1.5 mg C m3). Closer inshore, water column stratification became less pronounced with greater mixing evident. The most pronounced upwelling was observed at 20°N. Elsewhere in the region, the influence of strong upwelling on biological production was detected by elevated Chl a and fCO2 and lowered sea surface temperatures. In general, much higher phytoplankton biomass (maximum of 4875 ng Chl a l-1 at the 20°N upwelling) was encountered inshore (coccolithophores up to 2 mg C m3, dinoflagellates up to 8 mg C m3), and the assemblage was composed of a greater abundance and diversity of diatoms, ciliates, dinoflagellates, flagellates, cyanobacteria and coccolithophores. DMS 185
Eastern Boundary Upwelling Ecosystems Symposium was generally <2 nM offshore whilst more variable (up to 14 nM) at certain stations, which may have reflected the influence of the upwelling filaments. DLA was highest in the surface mixed layer, and the highest recorded value of DLA (45 nM h-1) was recorded alongside elevated DMS at the 20°N upwelling. These data are among the first coupled measurements of DLA, DMS, DMSP, and phytoplankton species composition in an upwelling system and indicate the highly dynamic nature of DMS production and its complex relationship with species composition.
Poster: P8 P17
Interannual variability of particle fluxes in the eastern South Pacific S. Giglio1,5, O. Pizarro1,2,3, M. Marchant4 and H. González6 Laboratorio de Procesos Oceanográficos y Clima, Barrio Universitario s/n, Cabina7, Concepción, T4146, Chile. Email:
[email protected] Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental, Chile. 3 Departamento de Geofísica, Universidad de Concepción, Chile. 4 Departamento de Zoología, Universidad de Concepción, Chile. 5 Magister en Ciencias con mención Oceanografía, Universidad de Concepción, Chile. 6 Instituto de Biología Marina, Universidad de Austral de Chile, Chile. 1 2
The upwelling system of the eastern South Pacific (ESP) is one of the most productive systems in the global ocean. In addition to the upwelling events, different advective and turbulent processes play an important role in the spatial and temporal variability of the primary production, spatial redistribution of the nutrients and planctonic biomass. Among them we can remark the mesoscale eddies and upwelling filaments. These processes modulate the biogeochemistry of the superficial ocean through horizontal and vertical transport of dissolved and particulated materials, particularly in a direction which is perpendicular to the coast. We analyse seasonal and interannual variability of particulated material fluxes off central Chile using long time series of sediments collected in a sediment trap located at about 2300 m depth in a line moored at about 150 km offshore near 30ºS over 4400 m depth. We relate fluxes variability, particularly organic carbon, carbonate and main planktonic foraminiferal, with changes in the offshore transport. The main hypothesis is that the interannual variability of the vertical fluxes of particulated material in the study region are modulated by changes in the offshore transport associated to mesoescale eddies and upwelling filament that reach the mooring site. Eddies and upwelling filaments were analysed using high resolution satellite images of TSM and Chl a, together with satellite altimetry and winds. Current meter data from two moorings were used to validate satellite information and directly evaluate the impact of current variability on vertical fluxes. Sediment trap and current time series expand from 1993 to 2004 including several El Niño and la Niña events. This work complements previous studies based on shorter records.
Poster: P8 P18
Does ETS activity follow Kleiber’s Law? M. Gómez, I. Martinez, and T. Packard Biological Oceanography Laboratory, Facultad de Ciencias del Mar. Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira. 35017 Las Palmas de Gran Canaria, Canary Islands, Spain. Email:
[email protected],es
Kleiber’s Law which relates organisms’ biomass (M) with metabolic rates (R) has been shown to follow the allometric equations: R=aM.0.75. This law has been found over a 20 order of magnitude of biomass for respiration and productivity, and over smaller ranges of magnitude for many other physiological processes. This law has gained increasing importance in recent years, because it serves as the basis for the Metabolic Theory of Ecology. Here we investigated whether or not Kleiber’s Law holds for potential respiration in marine zooplankton. Because the potential respiration is the Vmax of respiration, one would assume that like respiration, the potential respiration would also follow Kleiber’s Law. In a recent analysis, working with 5 phyla of marine zooplankton, both respiration and ETS activity did follow Kleiber’s Law. The allometric equation for respiration was R=1.5M0.76 and the equivalent equation for a potential respiration was Φ =3.3M0.79 indicating that the potential respiration is actually more closely related to biomass than respiration. But it is not known whether potential respiration follows Kleiber’s Law in natural zooplankton assemblages. To investigate this question samples of ETS activity and protein in the zooplankton from the northwest African upwelling systems were taken in Marzo of 2006 (CONAFRICA 0603). These samples included both offshore oceanic zooplankton, nearshore upwelling zooplankton and zooplankton from ten different depths to 200 m. These samples will be analysed by depth, for the two different regions, and for the complete samples agreement with Kleiber’s Law. 186
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Poster: P8 P19
Mesozooplankton biomass and enzymatic metabolic activities increases in the boundaries of island-generated eddies M. Gómez, S. Hernández-León, C. Almeida and S. Torres Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain. Email:
[email protected],es
Zooplankton biomass (as protein content), electron transport system (ETS) and glutamate dehydrogenase (GDH) activities have been studied around the island of Gran Canaria during the trade wind season. Four size classes (100-200, 200-500, 500-1000 and >1000 µm) were studied in order to know the contribution of each size fraction to the zooplankton distribution around the island. The highest zooplankton biomass values appeared to be related to the island shelf and also to the presence of an anticyclonic eddy southeast of the island. The smaller fractions (100-200 µm and 200-500 µm) showed maximum values on the shelf area while the higher values for the large fraction (>1000 µm) appeared related to the anticyclonic eddy. A common feature of all the fractions considered was the low biomass values at the center of the cyclonic eddy and an increase to their boundaries. Specific ETS and GDH activities showed two maxima at both the east and west sides of the island in the 100-200 µm fraction. Likewise, high values were observed in the cyclonic eddy boundaries. In the other size fractions, a maximum in the middle of the anticyclonic eddy was observed in addition to high values at the cyclonic eddy boundaries. The enhancement of biomass at the island shelf and the influence of the outward and inward effects of cyclonic and anticyclonic eddies observed in previous works were confirmed as a very important enrichment phenomenon affecting zooplankton accumulation and therefore the transport of organic carbon in the water column near the islands.
Poster: P8 P20
The role of the `biological pump´ in the Humboldt Current system off Chile: the significance of upwelling versus fjord systems H. González1,2,3, G. Daneri2,3, J. Iriarte3,4, E. Menschel1,2, R. Torres3, C. Vargas3,5 and R. Vera1,2 Institute of Marine Biology, Universidad Austral de Chile P. O. Box 567, Valdivia, Chile. Email:
[email protected] Center for Oceanographic Research in the Eastern South-Pacific (COPAS) Universidad de Concepción, Chile. 3 Patagonia Ecosystems Research Center (CIEP), Chile. 4 Institute of Aquaculture, Universidad Austral de Chile, Chile. 5 Aquatic Research Unit, EULA-Chile, Universidad de Concepción, Chile. 1 2
The vertical flux of particulate organic carbon (POC) with simultaneous estimations of primary production (PP) have been studied during the last 10 years by using free-drifting and anchored sediment traps in coastal and oceanic areas of the Humboldt Current System (HCS) off Chile. Euphausiids seems to be the key group as drivers of the biological pump due to the production of large, fast sinking faecal strings, accounting on average for 50% and 33% of total POC collected at shallow (100 m depth) and deep (2300 m depth) sediment traps along the HCS. In general, only a minor fraction of the produced zooplankton faecal pellets are exported below the productive layer of the ocean, this is mainly due to mineralization and utilisation processes exerted by bacteria and metazoans. However, the faecal material that exits the productive layer of the ocean before being recycled might constitute the main fuel of the POC pump in the HCS off Chile. Along the HCS off Chile the information on vertical fluxes of POC and PP in warm and temperate upwelling systems (range of 100-1000 and 100-10.000 mgC m-2 d-1, respectively) and cold fjord areas (range 119 – 477 and 100-4500 mgC m-2 d-1) showed a remarkable annual variability with higher values concentrated during the productive period (spring and summer). Preliminary information on ocean-atmosphere CO2 exchange and trophic carbon fluxes along the HCS off Chile suggests that during the productive period (1) the upwelling areas behave as a source and the Patagonia fjord region as a regional sink of atmospheric CO2, and (2) despite the POC flux and PP ratios not being substantially different in both areas, the higher relevance of the microbial loop in upwelling systems (than in cold fjord systems) seems to be one of the reasons for the reduced efficiency of the biological pump in this area.
187
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Poster: P8 P21
Condition of young Cape hakes M. capensis and M. paradoxus in the southern Benguela upwelling system off South Africa B. Grote1, W. Ekau2, W. Hagen1 and H. Verheye3 Marine Zoology, University of Bremen, Leobenerstr. NW2 Marine Zoology FB2, Postfach 330440, Bremen, 28359, Germany. Email:
[email protected] 2 Center for Tropical Marine Ecology (ZMT), Germany. 3 Marine and Coastal Management, South Africa. 1
Hake (Merluccidae) is one of the dominant fishes in upwelling regions in the Atlantic and Pacific Ocean. There are two species of hake off South Africa in the southern Benguela upwelling system. The shallow-water hake, Merluccius capensis, lives in inshore waters down to 380 m depth, whereas the deep-water hake, Merluccius paradoxus, inhabits waters from approximately 150 m down to 500 m depth. The commercial fishery of M. capensis and M. paradoxus is the largest sector of the South African fishing industry. Since 2000, there is evidence of a decline in the M. paradoxus stock and to a lesser extent in the M. capensis stock. The primary reason for decreasing stock size appears to be low recruitment in the late 1990s and too high fishing pressure on M. capensis. So far studies on recruitment of fish in the southern Benguela Current were concentrated on clupeoid species, whereas little is known about the early life history strategies of M. capensis and M. paradoxus. Fluctuations in recruitment have been shown to be due to high mortality during the early life stages of fish. Larval mortality by starvation is often highest during the critical life stage of first feeding. Therefore it is essential for a proper management of the resource to gain more information on the early life history of both hake species and to identify their ecological role in the southern Benguela ecosystem. Samples for this study have been collected on transects along the west coast of South Africa in the southern Benguela system, extending from southern Namibia around the Cape to the Agulhas Bank. On three cruises with the R/V Fritdjof Nansen samples were taken with a multiple opening/closing net (450 µm) and deep frozen for further biochemical analyses. Lipid content and the ratio of ribonucleic acid (RNA) to deoxyribonucleic acid (DNA) of single larvae were analysed as an indicator of larval condition. The lipid content reflects the quantity of energy reserves in larval fish. The RNA/DNA ratio functions as an index for the efficiency of protein synthesis within a cell. The nucleic acids were extracted and measured fluorometrically. Results will be discussed with emphasis on larval condition.
Poster: P8 P22
Phytoplankton community structure and its response to Chinese subtropical coastal upwelling using diagnostic pigments B. Huang, J. Hu, J. Chen and H. Hong State Key Laboratory of Marine Environmental Science, Environmental Science Research Center, Xiamen University, Xiamen, Fujian 361005, China. Email:
[email protected]
In order to understand the temporal (inter-annual) and spatial variations of phytoplankton (Chl a and assemblage) to the upwelling events in Chinese subtropical coastal upwelling (Taiwan Strait), field cruises were carried out during the summer of 2004 and 2007. Using field and remote sensing data, significantly inter-annual variations of summer upwelling and phytoplankton biomass (Chl a) were observed, which were the result of wind stress and current. Results also showed that diatoms dominated overall in the Taiwan Strait, however, phytoplankton assemblage varied with different water masses. Diatoms dominated in the upwelled water (>60%), whereas prochlorophytes (18%) and cyanobacteria (19%) showed the highest contribution in the upper warm water and coastal diluted water, respectively. Diatoms contributed almost 50% of Chl a in the subsurface water, whereas, diatoms (40%) and chlorophytes (19%) dominated in the mixed water. During the development and decline of upwelling event, phytoplankton community varied significantly, diatoms decreased gradually while cyanobacteria increased, and finally formed cyanobacteriadominance assemblage during decline process; diatoms increased while cyanobateria and chlorophytes decreased, formed diatom-dominance assemblage during the development process. Variation of nutrient inputs (nitrate and phosphate) was responsible for such succession of phytoplankton assemblages. Further study showed that nutrient stress of large phytoplankton (e.g. diatoms) got stronger and stronger with decline of the upwelling. All these results indicated that both phytoplankton biomass and community structure were quick to respond to nutrient inputs induced by upwelling in the study area. 188
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P8 P23
Size-fractionated biomass and productivity of phytoplankton in two areas of the Humboldt Current system off Chile: the role of diatoms in coastal upwelling and fjord systems J. Iriarte1,2, H. González2,3,4, G. Daneri2,4, C. Vargas2,5, M. Sobarzo6 and C. Valenzuela1 Institute of Aquaculture, Universidad Austral de Chile, P. O. Box 567, Puerto Montt, Chile. Email:
[email protected] Patagonia Ecosystems Research Center (CIEP), Chile. 3 Institute of Marine Biology, Universidad Austral de Chile, Chile. 4 Center for Oceanographic Research in the East South Pacific (COPAS) Universidad de Concepción, Chile. 5 Aquatic Research Unit, EULA-Chile, Universidad de Concepción, Chile. 6 Department of Oceanography, Universidad de Concepción, Chile. 1 2
Size fractionated biomass and primary productivity, the composition of the dominant species and their relationship with environmental factors in the upwelling area off Concepción and the southern chilean fjords system were studied during the 2005-2007 period. These areas are characterised by horizontal buoyancy input of freshwater from river run-off which had important ecological-oceanographic implications. Total phytoplankton biomass and total primary productivity from the upwelling and fjord areas varied greatly in magnitude (Concepción area: 100-10.000 mg C m-2 d-1; fjords: 100-4500 mg C m-2 d-1). Although microplankton (>20 µm) and nanophytoplankton (2 – 20 µm) contributed more (50 – 70%) to primary production and biomass in the upwelling area and the fjords region during spring seasons, picoplankton (<2 µm) was important (20 – 30%) during winter periods. Among the three fractions, microplankton accounted for most of the winter-spring variability in both systems, where large and chain-forming diatoms were important contributors to phytoplankton assemblages. The high autotrophic biomass and primary productivity estimates at both areas were associated to higher stability of the water column, being favourable to growth of cold water phytoplankton.
Poster: P8 P24
Respiration physiology of fish larvae and krill from the Benguela system A. Kunzmann and F. Buchholz ZMT Bremen, AWI Bremerhaven, Fahrenheitstr. 6, Bremen, 28359, Germany. Email:
[email protected]
Studies on metabolism provide insight into energy requirements of animals. The common method to estimate metabolism is to measure or calculate a Standard or Routine Oxygen Consumption (SOC or ROC). Areas with variable oxygen concentrations, such as the Benguela Current system, are a challenge for fish and crustacean zooplankton. Numerous experimental studies have demonstrated that pelagic fish larvae respond negatively to low oxygen concentrations in terms of their behaviour and/or survival. On the other hand it has been demonstrated that both krill and benthic fish occur in low oxygen areas of 1 ml/l and less. Little is known about the oxygen tolerance of fish larvae of different species and at which levels oxygen becomes critical for their survival. During a cruise to the western Benguela region in February 2007, oxygen consumption experiments with fish larvae and krill have been performed. Both intermittent flow respirometer and closed bottle respirometer with different oxygen probes have been used. Larvae of flat fish (Soleidae), Leptocephalus (Anguilliformes), sardines (Clupeidae) and krill (Euphausia hanseni) were measured and subsequently frozen at -80 °C for later taxonomic identification and for biochemical analysis. Preliminary results indicate that krill tolerate low oxygen levels down to 30% saturation. Some individuals even survive after several hours of exposure down to 10% saturation. 5% oxygen seems to be the final limit. This is in contrast to Leptocephalus larvae, which easily tolerate oxygen saturation levels of 5%. Two individuals were kept for more than three hours at almost zero oxygen without any harm. Also the flatfish larvae tolerated low oxygen saturation. At levels of 10% they responded with increased ventilation rates, which at 5% turned to fast pumping. All individuals recovered within minutes after oxygen levels were raised again to 50% and more. Long-term experiments, also using fish larvae and juveniles of different size classes and krill groups of 15-20 individuals with gradually and controlled oxygen levels of are planned for future measurements. 189
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Poster: P8 P25
Phytoplankton photosynthesis in the southern Benguela T. Lamont1, R. Barlow1, M. Kyewalyanga2 and H. Sessions1 Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay, Cape Town, 8012, South Africa. Email:
[email protected] 2 Institute of Marine Sciences, University of Dar-es-Salaam, Zanzibar, Tanzania. 1
Photo-physiological studies of phytoplankton photosynthesis were conducted in the southern Benguela (29oS-34.5oS) in October 2006 and May 2007, utilising 14C photosynthesis-irradiance (P-E) experiments, fast repetition rate fluorometry, phytoplankton absorption, PAR and pigments analysed by HPLC. Broadband P-E parameters, (i.e. PsB (mg C [mg Chl a]-1 h-1), αB (mg C [mg Chl a]-1 h-1 [µmol m-2 s-1]-1) were estimated by fitting the chlorophyll a normalized hourly production rates to the continuous exponential model of Platt et al. (1980). The 14C P-E parameters for October 2006 showed that αB values ranged from 0.0174 to 0.4035 mg C [mg Chl a]-1 h-1 [µmol m-2 s-1]-1. The corresponding PsB values ranged from 0.5750 to 12.8100 mg C [mg Chl a]-1 h-1. During May 2007, the αB values ranged from 0.0091 to 0.4757 mg C [mg Chl a]-1 h-1 [µmol m-2 s-1]-1, while the corresponding PsB values ranged from 0.1753 to 35.9500 mg C [mg Chl a]-1 h-1. These parameters were used together with HPLC chlorophyll a concentrations and in situ PAR to estimate primary production. Integrated primary production was generally higher during October 2006, varying from 0.850 to 8.611 g C m-2 d-1, and lower during May 2007, varying from 0.690 to 3.330 g C m-2 d-1. Variability in primary production in October 2006 was more closely associated with changes in phytoplankton biomass than with P-E parameters. During May 2007, primary production variability appeared to be explained by differences in photo-physiological parameters and selected examples are presented to illustrate these differences.
Poster: P8 P26
Spatial variability of invertebrate larvae around Gran Canaria Island J. Landeira1, F. Lozano Soldevilla2, S. Hernández-León1 and E.D. Barton3 Universidad de Las Palmas de Gran Canaria, C/Cantillo Abajo, 25,1, Los Realejos, Santa Cruz De Tenerife, 38419, Spain. Email:
[email protected] 2 University of la Laguna, Santa Cruz de Tenerife, Spain 3 Departamento de Oceanografía, Instituto Investigaciones Marinas, Spain. 1
In October 1991, invertebrate larvae were studied in the waters surrounding the island of Gran Canaria (Canary Islands). The cruise was typified by the presence of three recurrent mesoscale hydrological structures: a cyclonic eddy, southwest of the island, a warm lee region downstream of the island and the offshore boundary of an upwelling filament from the African coast reaching the southeast of the island. Decapod larvae were the most abundant group. In general, a rather high spatial variability was found. The horizontal distribution of the different invertebrate larvae groups showed that highest values of abundance occurred in the band near the island oriented with the overall direction of flow and the lowest values occurred in the north and the flanks of the islands. On the other hand, stomatopoda and mollusca larvae presented a distribution associated with the boundary of the upwelling filament and decapod larvae of pelagic species distributed around the eddy structure. Our results suggest specific retention mechanisms for the larvae of neritic invertebrate populations around Gran Canaria related to the particular physical oceanography of the area.
Poster: P8 P27
The influence of upwelling filaments and island-induced eddies on the decapod larvae distribution in the Canaries Coastal Transition Zone J. Landeira1, F. Lozano Soldevilla2, S. Hernández-León1 and E.D. Barton3 Universidad de Las Palmas de Gran Canaria, C/Cantillo Abajo, 25,1, Los Realejos, Santa Cruz De Tenerife, 38419, Spain. Email:
[email protected] 2 University of la Laguna, Santa Cruz de Tenerife, Spain. 3 Departamento de Oceanografía, Instituto Investigaciones Marinas, Spain. 1
The distribution and transport of decapod larvae were studied along a filament-eddy system located in the transition zone between the NW Africa upwelling and Canary Islands waters during the summer of 1999. Two independent filaments were developed between Cape Juby and Cape Bojador to merge at 100 km 190
Eastern Boundary Upwelling Ecosystems Symposium offshore during the cruise. The merged filament interacted with transient cyclonic and anticyclonic eddies shed from the island of Gran Canaria. Mesoscale oceanographic features strongly influenced the horizontal distribution of decapod larvae. Benthic larvae were mainly associated with upwelling filament structures, while oceanic larvae were related with eddies structures. In this sense, eddies acted as a mechanism of concentration, while upwelling filaments were dispersive, transporting larvae from the African neritic zone into oceanic areas and towards the Canary archipelago. This study suggests that there are clear evidences of connectivity between marine populations of African and Canaries coast.
Poster: P8 P28
Microplankton role in the carbon flux of a coastal upwelling area off northern Baja California, Mexico L. Linacre1, R. Lara-Lara2, J.M. Hernández-Ayón3 and M. Landry4 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Apartado Postal 453, Ensenada, Baja California, 22800, Mexico. Email:
[email protected] 2 Departamento de Oceanografía Biológica, CICESE, Mexico. 3 Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Mexico. 4 Integrative Oceanography Division, Scripps Institution of Oceanography, USA. 1
CO2 dynamics in coastal areas is very complex, especially in upwelling systems. Seasonal variability in carbon atmosphere-ocean fluxes depends not only on chemical and physical processes, but also on biological parameters, like trophic and plankton community structures and microplankton grazing impact on primary production. In this work, we evaluate the role of microplankton communities within the euphotic layer on organic and inorganic carbon fluxes associated with seasonal upwelling events in northern Baja California (Mexico). Specifically, we seek to estimate the seasonal variability of growth and mortality (grazing) rates of autotrophic organisms consumed by microzooplankton. This work is part of a Mexican project called FLUCAR (Carbon Flux: Sources and Sinks in Continental Margins of Pacific Mexican Waters). Historical analysis of hydrographic data (CalCOFI period 1950-1978 and IMECOCAL period 1997-2006) shows that the study area is characterised by a seasonal variability in physical and chemical conditions associated with upwelling events, which are strongest during the spring-summer season. The data also shows that this region is part of a “Coastal Upwelling System” (CUS) that spans a narrow coastal band (100 km) from Ensenada (31.7oN) to Bahía San Quintín (30.5oN), Mexico. Thus, seasonal variability of the biological processes and community structure is expected to be associated with upwelling and nonupwelling periods. We will present initial field and laboratory results of this project with an emphasis on seasonal variability in the phytoplankton growth and grazing balance. These results will contribute to future carbon budgets for this coastal upwelling area.
Poster: P8 P29
The size-structured community of mesozooplankton off central Chile (36°S) in the eastern boundary Humboldt Current as assessed by ZooImage analysis K. Manríquez1, R. Escribano1,2 and P. Hidalgo2,3 Department of Oceanography, Universidad de Concepción, P.O. Box 160 C, Concepción, Chile. Email:
[email protected] COPAS Center, Universidad de Concepción, Chile. 3 Instituto de Biología Marina, Universidad Austral de Chile, Chile. 1 2
The highly productive upwelling zone off Central/southern Chile contains a rich community of zooplankton dominated by calanoid copepods and euphausiids. A zooplankton time series study over the continental shelf (2002-2005) and a spring survey in 2004 allowed us to examine temporal and spatial variability of these two components, on the basis of digital analysis of samples using the ZooImage software (http:// www. Sciviens.org). Using this approach, we assessed zooplankton biomass, and the size-structured community in association with oceanographic variability. Over the cross-shelf axis there are not significant changes in the size spectra when comparing the upwelling vs the non-upwelling (offshore region). Over the temporal scale, there are significant year-to-year changes in the size spectra during the upwelling season 191
Eastern Boundary Upwelling Ecosystems Symposium (August-March). Size-categorised groups from ZooImage analysis showed much consistency with our previous standard zooplankton analysis of copepod and euphausiids species. Oceanographic conditions commanded by seasonal upwelling appeared to exert a strong influence on the zooplankton community. ZooImage proved as a useful tool to assess the patterns of spatial and temporal variation of biomass and size-structured numerical abundance. Interannual variation seems highly relevant in such context. However, observed changes in size categories and biomass distribution are clearly better understood when considering the actual species involved. Species phenology and their life-cycles may be key components driving changes in the community in response to upwelling variation.
Poster: P8 P30
Temporal and spatial variation in the distribution of adult and juvenile Euphausia pacifica and Thysanoessa spinifera in the northern California Current for the years 1998 through 2006 J. Menkel1 and W. Peterson2 Cooperative Institute for Marine Resources Studies, Hatfield Marine Science Center, 2030 S. Marine Science Drive, Newport, OR 97365, USA. Email:
[email protected] 2 Northwest Fisheries Science Center, Hatfield Marine Science Center, USA. 1
The euphausiids Euphausia pacifica and Thysanoessa spinifera are an essential food web link between primary production in the ocean and commercially harvested fish species, as well as marine mammals, and seabirds. We have analysed adult and juvenile euphausiids from hundreds of vertical net samples taken at night in the Northern California Current, 1998-2006. Understanding the distribution and the inter-annual and seasonal variability in abundances of Euphausia pacifica and Thysanoessa spinifera, and how these species respond to climatic changes, is necessary in order to understand ocean productivity and food web dynamics. We have identified the Cape Blanco area and Heceta Bank area as geographical hot spots in euphausiid abundance for both species. We hypothesise that these hot spots occur due to topography, circulation patterns, and the strong upwelling conditions that tend to concentrate euphausiids in these areas. We will explore the seasonal differences in the location of the population centers as well as the yearly changes in biomass due to inter-annual differences in ocean conditions.
Poster: P8 P31 Micro and mesozooplankton biomass during the late winter bloom in the Canary Islands waters C. Schmoker and S. Hernández-León Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain. Email:
[email protected]
Micro and mesozooplankton biomass were measured in the Canary Islands waters in order to study the characteristic late winter bloom of subtropical waters. Weekly sampling was performed between January and August 2005 in 6 stations around Gran Canaria Island. Microplankton size fractions (2-200µm) were measured using a Flowcam. Mesozooplanktonic biomass was estimated measuring the dry weight in two size fractions (smaller and larger than 1 mm). Different peaks of micro and mesozooplankton biomass were observed from March to May. Mesozooplankton and small microplankton (<50 µm) showed similar trends during the late winter bloom, whereas microzooplankton in the size range of 50-200µm showed an inverse pattern. The observed bloom in mesozooplankton followed the lunar cycle recently described as the effect of predation by diel vertical migrants in epipelagic waters. Our results suggest the existence of a top-down control of mesozooplankton on microzooplankton releasing the biomass of microplankton (<50 µm). The trophic interactions in subtropical oceanic waters seem rather complex and the effect of diel vertical migrants on epipelagic mesozooplankton suggests cascade effects of unknown consequences for fish larvae and the ocean biogeochemistry. 192
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Poster: P8 P32
Euphausiid population dynamics in the coastal upwelling zone off the Oregon Coast, USA C. Shaw1, L. Feinberg1 and W. Peterson2 Cooperative Institute for Marine Resources Studies, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365, USA. Email:
[email protected] 2 Northwest Fisheries Science Center, NOAA Fisheries, USA. 1
Adult and juvenile euphausiids have been sampled along a transect off Newport, Oregon, USA, twice per month since 2001. The dominant euphausiid species in this system are Euphausia pacifica and Thysanoessa spinifera. The euphausiid data set includes information on species composition, length, sex, growth rate, and brood size. Surface Chl a is also measured at each station. Physical data are available in this area to determine the onset, duration, and intensity of the upwelling season. The time period of this data set (2001-2007) has encompassed warm and cold years (positive vs. negative PDO) as well as differences in upwelling conditions (strong, weak, late onset, etc.). E. pacifica were present during most sampling attempts, while T. spinifera were more variable and were rare or absent during much of 2005-06. E. pacifica biomass was usually 10-50 mg C m-3, with occasional higher values from 150-300 mg C m-3 near the shelf break. T. spinifera biomass was generally <5 mg C m-3, with occasional higher values from 11-25 mg C m-3 at mid- to outer-shelf stations. Average summer (July-Sept) E. pacifica biomass showed a marked increase from inshore (3 mg C m-3) to offshore (22 mg C m-3) while T. spinifera biomass was from 1-5 mg C m-3 at all stations. As a comparison, overall copepod biomass decreased from 15 mg C m-3 inshore to 7 mg C m-3 offshore. We will examine the relationship between biomass and upwelling to determine how specific upwelling conditions affect the biomass of euphausiids. Euphausiid growth rates were highly variable and were not noticeably affected by inter-annual differences in temperature or upwelling conditions. However, euphausiid egg production was strongly affected, as euphausiids did not spawn until the upwelling season was initiated and phytoplankton blooms were established. The timing of spawning by euphausiids seems to be closely tied to upwelling, therefore changes in the timing or strength of upwelling are likely to result in changes in the reproductive behavior of euphausiids in our study area.
Poster: P8 P33
Relative distribution of phytoplankton and mesozooplankton in the upwelling system off NW Portugal L. Sobrinho-Gonçalves, T. Moita and E. Cunha IPIMAR, Av. de Brasília, 1449-006 Lisbon, Portugal. Email:
[email protected]
The biological and physical oceanographic conditions of the NW coast of Portugal were surveyed along a cross-shelf transect in 2002 (spring and summer) and 2003 (winter and late summer). Fifty-one stations were sampled for hydrographic information, phytoplankton (six depth levels) and mesozooplankton (five depth strata of 25m). Phytoplankton presented a temperate region seasonal pattern, with a minimum in winter and maximum concentrations in spring and late summer. Spatial distribution of phytoplankton (namely across the shelf) was forced by environmental parameters, with offshore transport due to north winds stress and onshore transport related to wind relaxation or south winds. Phytoplankton showed a seasonal succession of species, with diatoms dominating mixed and upwelled waters whereas dinoflagellates prevailed in thermally stratified conditions. Mesozooplankton abundance accompanied the seasonal pattern of phytoplankton biomass nearshore, confirming its trophic dependence on diatoms and dinoflagellates, while offshore (shelf edge) the same pattern was not observed. Mesozooplankton was distributed close to the phytoplankton patches (especially at inner/mid-shelf) but was less influenced by wind forcing. Copepods dominated the mesozooplankton, with only seven taxa accounting for half the community. The seasonal succession in mesozooplankton was less clear than for phytoplankton due to a change in the community structure from 2002 to 2003, with replacement of dominant species. The relative composition of mesozooplankton showed no differentiation with depth, while across the section we identified a nearshore cluster of taxa and a widespread cluster (that included some offshore elements). Localised deepenings of surface water, associated with upwelling events, may have forced a decrease of phytoplankton and mesozooplankton that was repeatedly observed at the outer-shelf during spring and 193
Eastern Boundary Upwelling Ecosystems Symposium summer. The temporal/spatial variability of interactions between mesozooplankton taxa assemblages and phytoplankton groups was considered, resulting in the detection of a grazing “hot spot” (affecting larger microalgae) at mid-shelf, under strong thermal stratification, and also indicating that several widespread abundant copepods can alter their herbivorous regimes off the continental shelf.
Poster: P8 P34
The microbial food web in the coastal upwelling system of the Ría de Vigo (NW Iberia) I. Teixeira, B. Crespo, S. Piedracoba and F. Figueiras Instituto de Investigacións Mariñas (CSIC), Eduardo Cabello, 6, Vigo 36208, Spain. Email:
[email protected]
The impact of microzooplankton (phagotrophic organisms <200 µm) on the planktonic community has been estimated in the Ría de Vigo, a coastal embayment on the NW Iberian peninsula which is affected by upwelling events. A total of 8 dilution experiments were performed during 2002, in which changes in the several components of the plankton community <200µm have been determined through microscopic counts. This allowed us to estimate the impact of microzooplankton on both autotrophic and heterotrophic organisms during different seasons. On average, around 40% of the total standing stock and 60% of all production of the plankton community <200µm were consumed daily by microzooplankton, although all production could be consumed during certain periods. Heterotrophic bacteria and heterotrophic picoflagellates were consumed all through the year, which suggests that large fractions of their standing stock and production were channelled through the microbial food web. Small phytoplankton also grazed all through the year, but microzooplankton impact on these organisms was lower when compared with that on the small heterotrophs. Grazing on diatoms was higher during summer upwelling events, when chain-forming species were grazed by the large heterotrophic dinoflagellates found in the microzooplankton community in that period. Even though microzooplankton impact was very important through out the year, mainly on small organisms, it was during the July upwelling events when microzooplankton consumed the highest quantities of carbon and had the highest impact on the standing stock of the plankton community <200µm. This work provides additional evidence as to the important role that microzooplankton can have in coastal and upwelling systems as consumers of several groups of the plankton community <200µm. It also suggests that the microbial food web in these systems must increase the quantities of carbon available for larger consumers, if only the classical food web was present.
Poster: P8 P35
Comparing the dynamics of the nearshore and the offshore Humboldt Current system trophic webs: the role of fisheries, environmental drivers and trophic relationships M. Wolff1, M. Taylor2, J. Mendo3, J. Tam4 and C. Yamashiro4 Fundacion Charles Darwin, Pto. Ayora, Santa Cruz, Ecuador. Email:
[email protected] Center for Tropical Marine Ecology, Germany. 3 Universidad Agraria La Molinal, Peru. 4 Instituto del Mar del Peru, Peru. 1 2
Steady-state models of Tam et al. (in press) for the northern Humboldt Current ecosystem (NHCE) and for two bay systems at the Peruvian central coast (Independencia, 12.30°S) and at the northern border (Sechura, 5.6°S) were subjected to simulations with IMARPE time-series data for the period 1995-2004 using the program Ecopath with Ecosim (EwE). Results showed that changes in phytoplankton quantity and quality (i.e. contribution of diatoms and dino- and silicoflagellates), as affected by upwelling intensity, was the most important driver in reproducing ecosystem dynamics associated with the El Niño event of 1997/98. Simulated longer-term dynamics from 1995-2003 were improved through a combination of all three drivers (Phytoplankton – PP, Fishing – F, Immigrants – I), with fishing rates being the most important. Internal control settings show a mix of interactions; however a “wasp-waist” configuration around small pelagic fish was not supported. Changes observed over the El Niño cycle in two nearshore systems were mainly caused by environmentally driven, non-trophic, and non-fishery induced population responses (temperature dependent increase in scallop recruitment, and mortality of crabs and macrophytes during the El Niño warming in Independencia Bay, and temperature and river discharge related growth and mortalities of scallops in Sechura bay). Trophic interactions could explain some of the observed changes 194
Eastern Boundary Upwelling Ecosystems Symposium in Independencia bay (decrease in the groups benthic detritivores, miscellaneous filter feeders, herbivorous gastropods and polychaetes, and an increase in the groups pred. gastropods, small carnivores, sea stars and octopus) but less so in Sechura bay, where neither trophic drivers, nor fishing rates did significantly increase the fit between observed and simulated changes. We conclude from our studies that within the large Humboldt Current system, subsystems subjected to strong outside influences or bordering variable water masses (such as the Sechura system in the transition zone between the cold Humboldt current of the Peruvian province and the warm topical water masses of the Panamian province) may be less predictable from a trophic modelling perspective than others, more closed and of a central position within the current system (such as the Independencia system). We stress the importance of spatial scale considerations if system features are to be compared between different upwelling systems or between subsystems of the same larger system.
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P9
Small pelagic fishes and the functioning of EBUS
3 June, 15:15 (P9 KNS)
The role of small pelagic fishes in the functioning of eastern boundary upwelling systems C. van der Lingen1,2, J-P. Roux3 and L. Shannon1 Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa. Email:
[email protected] 2 Marine Biology Research Institute, Zoology Department, University of Cape Town, South Africa. 3 Ministry of Fisheries and Marine Resources, Namibia. 1
Small pelagic fishes (primarily anchovies of the genus Engraulis and the sardines Sardina pilchardus and Sardinops sagax) are a defining feature of the world’s four eastern boundary upwelling systems, where they often comprise the bulk of fish biomass and support large fisheries. These species are characterised by rapid growth, high fecundity, a short lifespan, marked interannual variability in recruitment strength, and high and variable natural mortality, all of which contribute to a high degree of variability in population size. Whilst interannual variability in population size is characteristic of small pelagic fishes these species also show decadal-scale variability in population size, and species alternations between small pelagic fish at decadal scales have been reported for all of the eastern boundary systems. Small pelagic fishes feed on both phytoplankton and zooplankton and are typically the principal forage fish in eastern boundary upwelling systems, being the dominant prey of a variety of fish, marine mammal and seabird predators. Hence they occupy a mid-trophic-level position and mediate the transfer of energy from lower to higher trophic levels. Their central position in these “wasp-waist” systems (so-called because of the small number of species that occupy this mid-trophic-level position), and their control of flows to trophic levels both above and below, means that small pelagic fishes are key determinants in the ecological functioning of eastern boundary upwelling systems. Because of this, changes in the abundance, relative species dominance, and distribution of small pelagic species within an ecosystem will have significant and substantial impacts on ecosystem structure and functioning.
The ecological role of small pelagic fishes in eastern boundary upwelling systems is illustrated using examples of interactions between these species and their predators and prey. The effects on upwelling systems of changes in the abundance of small pelagic fish, or changes in their distributions within an ecosystem, are also described. Whereas examples are taken primarily from the Benguela Current system off southern Africa, examples from the other eastern boundary upwelling systems are also described. Top-down control of zooplankton by small pelagic fishes has been reported, with inverse relationships between zooplankton abundance and pelagic fish abundance observed over decadal scales. Changes in zooplankton community and size structure may also be a consequence of top-down control due to differential size-selective predation on zooplankton by different small pelagic fish species. However, zooplankton composition in upwelling systems may itself be subject to bottom-up control arising from changes in phytoplankton community and size structure, and prevailing oceanographic conditions, and small pelagic fish are themselves sensitive to environmental perturbation. Small pelagic fishes also exert bottom-up control on their predators, with changes in the abundance of predators of small pelagic fish being linked to fluctuations in the biomass of their prey. Declines in predatory fish abundance rapidly follow declines in small pelagic abundance, whilst predator recovery after prey recovery can be either immediate or delayed. Predatory fish, particularly large pelagic species, have large foraging ranges and hence are less affected by changes in the distribution of small pelagic fishes than are other predators such as some marine mammal and seabird species that either have limited foraging ranges or are constrained to foraging in particular areas because of breeding site fidelity. For these latter predators, changes in prey distribution may be as detrimental as a reduction in prey abundance, and predators may have to switch to alternate prey, if available, that may be insufficient (e.g. in terms of energetic content) for their needs. Fluctuations in breeding success in the short term, and population size in the long term of several seabird species in eastern boundary upwelling systems have been related to changes in either the abundance of the availability (or both) of their prey. 196
Eastern Boundary Upwelling Ecosystems Symposium In addition to examining interactions between small pelagic fishes and their predators and prey, insights into the role that small pelagic fish play in eastern boundary upwelling systems may be gained from examining ecosystem functioning in a system where these fish have virtually disappeared. This is presently the case in the northern part of the Benguela Current system, where sardine biomass during recent decades has been <2% of peak biomass levels observed some 50 years ago, and sardine have not been replaced by anchovy. The northern Benguela is therefore essentially without typical small pelagic fish species (although they appear to have been partially replaced by a pelagic goby) and has lost its wasp-waist configuration. This change in food web structure appears to have drastically reduced the efficiency of energy transfer from lower to upper trophic levels and has resulted in a changed ecosystem. The underutilisation of phytoplankton arising from the collapse of the sardine population is likely to have increased detritus loads, resulting in a greater portion of the primary production now being used by benthic organisms and/or entering the bacterial loop than was the case when sardine was abundant. The increased detritus load has been hypothesized as contributing to increased anoxic conditions, and an increased incidence of sulphur eruptions, on the Namibian shelf. Hence the loss of small pelagic fish from the northern Benguela has resulted in substantial, and possibly irreversible, changes to ecosystem functioning, emphasizing the crucial role that these fish play in this and other eastern boundary upwelling ecosystems.
3 June, 15:45 (P9 OP1)
Spatio-temporal variability in fatty acid trophic biomarkers in stomach contents and muscle of Iberian sardine (Sardina pilchardus) and its relationship with upwelling and spawning S. Garrido1, R. Rosa2, R. Ben-Hamadou3, E. Cunha4, A. Chícharo3 and C. van der Lingen5 Univ. Lisbon/IPIMAR/ICM-CSIC, Av. Brasilia s/n, Lisbon 1449-006, Portugal. Email:
[email protected] Department of Technological Innovation and Upgrading of Fishery Products (DITVPP), Inst. de Investigação das Pescas e do Mar, Portugal. 3 CCMAR, Universidade do Algarve, Portugal. 4 CRIP-Sul, Inst. de Investigação das Pescas e do Mar, Portugal. 5 Marine and Coastal Management, South Africa. 1 2
Temporal variation in the fatty acid (FA) composition of stomach contents of Iberian sardines was compared to the relative contribution to dietary carbon made by different prey types for fish from two areas off Portugal. These areas are characterised by different feeding environments: the west coast of Portugal where stronger and more frequent seasonal upwelling events occur, and the south coast of Portugal, where these events are rarer and weaker. The effect of the FA content of the diet on sardine muscle fatty acid composition was also studied, aiming at 1) analysing if FA biomarkers can be used as a complementary technique for the study of sardine diet and 2) to relate spatial and temporal variations of prey FA content with sardine condition and reproduction. Significant spatial differences in the FA composition of sardine diet occurred with concentrations of n-3 polyunsaturated FA, namely eicosapentaenoic acid (EPA, 20:5n-3) and linolenic acid 18:3n-3, being significantly higher in the diet of sardines from the west coast, whilst the diet of sardines from the south coast was richer in monounsaturated fatty acids (MUFA), namely the carnivory biomarker oleic acid 18:1n-9. These results are in agreement with the higher contribution made by diatoms and dinoflagellates to the diet of sardines off the west coast. Spatial variation in sardine dietary FA was also detected in their muscle composition, specifically for EPA, and the EPA/DHA and (n-3)/(n-6) ratios, which were higher in sardines from the west coast. No difference in FA composition was detected between sexes, and the seasonal variability in sardine total FA concentration was primarily related to the seasonality of spawning. Sardines accumulate high concentrations of fatty acids during the resting stage of reproduction when the feeding intensity is similar or lower to that observed during the spawning season. Additionally, sardines show a high selective retention of MUFA and polyunsaturated FA (PUFA) throughout the year except at the beginning of the spawning season, when these FAs are largely invested in the formation of the gonads. Therefore, temporal and regional differences of prey environments are strong enough to be reflected in fish body composition, namely on the accumulation of essential fatty acids, which can have a strong impact on reproduction success for this species and apparently those living in regions with enhanced productivity related to the occurrence of upwelling events might have advantage. 197
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3 June, 16:00 (P9 OP2)
Trophic ecology of the sardine Sardinops sagax in the northern Humboldt Current system: filling the gap for a comparison between small pelagic fish from eastern boundary upwelling systems P. Espinoza1, A. Bertrand1,2, C. van der Lingen3 and B. Rojas de Mendiola1 Instituto del Mar del Peru, Esquina Gamarra y Gral. Valle s/n, Apartado 22, Callao, Lima, Peru. Email:
[email protected]. IRD, Peru. 3 Marine and Coastal Management, South Africa. 1 2
Sardine Sardinops sagax and anchoveta Engraulis ringens are the main small pelagic fish resources in the Humboldt Current system (HCS), and sardine and anchovy are also important in other eastern boundary upwelling systems where they play important ecological roles as predators of plankton and prey of top predators. However, despite the importance of sardine in the HCS knowledge on the trophic ecology of this species is scarce. Recently, Espinoza and Bertrand (2008) applied an analytical method to describe the diet of anchoveta off Peru by estimating prey carbon content and determining relative contribution to dietary carbon. Those results showed that anchoveta derive the majority of their dietary carbon from euphausiids and calanoid copepods, in contrast to previous perceptions of HCS functioning that considered phytoplankton to be anchoveta’s major dietary component and hypothesised a 2-step trophic chain between diatoms and fish. In this study we describe sardine diet in the northern HCS by applying the same analytical method used to characterize anchoveta diet to 651 sardine stomachs collected during seven surveys performed by IMARPE (Instituto del Mar del Peru) from 1996-98. Our results showed that the diet of sardine off Peru is based primarily on zooplankton and hence is similar to that of anchoveta, but with several important differences. Firstly, sardine feed on smaller zooplankters than does anchoveta, with sardine diet composed of smaller copepods and less euphausiids than anchoveta diet. Secondly, whilst phytoplankton represents <2% of sardine dietary carbon this fraction is dominated by dinoflagellates, whereas diatoms are the dominant phytoplankton consumed by anchoveta. Thirdly, sardine diet is more diverse than that of anchoveta. This new information we provide on sardine diet off Peru enables a comprehensive comparison of the trophic dynamics of small pelagic fish in the northern HCS - trophic competition between sardine and anchovy in this system is minimized by (i) their spatial segregation, with sardine associated with oceanic and frontal waters compared to anchoveta which is restricted to the productive cold coastal waters, and (ii) the partitioning of their zooplankton food resource based on prey size. These trophic differences between sardine and anchovy in the northern HCS have been reported in other upwelling systems (e.g. Benguela, California, and Kuroshio systems), and may be partially responsible for the long-term changes observed in the relative abundance of these species in eastern boundary upwelling systems (EBUS) as synthesised by van der Lingen et al. (2008).
3 June, 16:15 (P9 OP3)
Small pelagic fish reproductive strategies in upwelling systems: a homing evolutionary model to study environmental constraints T. Brochier1, F. Colas2, V. Echevin3, X. Capet4, C. Lett5, C. Mullon1 and P. Fréon1 IRD, UR ECO-UP, Centre de Recherche Halieutique Méditerranéenne et Tropicale, avenue Jean Monnet, BP 171 34203 Sète Cedex, France. Email:
[email protected] 2 Institute of Geophysics and Planetary Physics (IGPP), University of California, USA. 3 LOCEAN, Université Pierre et Marie Curie, France. 4 Instituto Oceanografico, University of Sao Paulo, Brazil. 5 IRD, UR Geodes, Institut des Systèmes Complexes, Ecole Normale Supérieure de Lyon, France. 1
Small pelagic fish populations in upwelling systems have a reproductive strategy resulting from past natural selection pressure that made them adapted to the constant structural instability of the area where they persist. Although little is known about the individual-level mechanisms of reproductive strategy, it has been shown that the observed anchovy spawning patterns in the southern Benguela Current system off South Africa could be reproduced well by simulating a natal homing reproductive strategy, i.e., individuals spawning at their natal date and place. Here we used a similar method, i.e. a natal homing evolutionary individual-based model (IBM), and applied it to other upwelling systems: the northern and 198
Eastern Boundary Upwelling Ecosystems Symposium southern Humboldt off Peru (off Peruand off Chile respectively) and the northern African Canary off Morocco. This allowed us to investigate and compare the selective constraints, during early life, leading to the observed spawning patterns of the species of sardine and anchovy living in the respective areas. In the evolutionary IBM, two processes were implemented: (1) an evolutionary-based reproductive strategy for adult fish, the natal homing, in which all adults spawned at their natal date and place; (2) a passive transport phase for eggs and larvae, leading to their recruitment provided the environment (temperature and food availability) they encountered was favourable. Recruited individuals were the spawners of the next simulated generation, which was confronted with different environmental conditions, and so on. This loop was repeated several times, allowing a spatio-temporal spawning pattern to emerge. Environmental conditions were provided by simulations of a three-dimensional hydrodynamic model (ROMS) of the different areas, previously generated with climatological and/or interannual forcing. The selective environmental constraints tested were: (1) lethal temperature; (2) retention in the areas with large food availability; (3) avoidance of dispersive structures (that may prevent food concentration, and enhance individual straying. These criteria were the subject of a detailed study in the Peruand Canary upwelling systems. Preliminary results showed that the retention and non-dispersion constraints were sufficient to reproduce the observed spawning areas well in the northern Humboldt and northern African Canary, while lethal temperature had only a limited impact, in contrast with the results obtained in the southern Benguela. Acknowlegements: This work was supported by EUR-OCEANS, a European Network of Excellence co-funded by the European Commission (6th Framework Programme, contract n°511106).
3 June, 16:30 (P9 OP4)
Does the behaviour and life history strategy of Maurolicus muelleri reflect local adaptations to environmental conditions? A comparison between the oceanic northern Benguela and fjordic Masfjorden A. Staby, A. Gro Vea Salvanes and A. Fernø Department of Biology, University of Bergen, P O Box 7803, Bergen, 5020, Norway. Email:
[email protected]
The pearlside Maurolicus muelleri is common worldwide, but how the species adapts to different environments it is not clear. Here we review current literature on behaviour and life history strategies in the very productive northern Benguela current region and the well studied Norwegian fjord Masfjorden. In both environments fish are exposed to diurnal changes in light levels, gradients in salinity, temperature, and oxygen, currents and predation. Large areas of hypoxic waters and severe episodes of sulphide eruptions are additional challenges fish in the northern Benguela have to face. Differences in several aspects of the life history are indicated from the available data. The M. muelleri in the northern Benguela region has a shorter lifespan, but a higher growth rate and size related batch fecundity, larger eggs and a longer spawning season than in Masfjorden. Higher overall system productivity and higher temperatures may explain the rapid growth in the Benguela. The higher reproductive effort could be an adaptation to the higher unpredictability of the northern Benguela region with a higher total loss of all life stages. There is a higher predation risk and also a risk during upwelling events of advective transport of early life stages to unsuitable environments. The various life stages may in addition be exposed to sulphurous and hypoxic water masses, representing an additional mortality risk. In both locations M. muelleri makes diel vertical migrations and at least in Masfjorden these vary during the ontogeny of the fish and time of year. When ascending during dusk into shallower waters and descending during dawn into deeper waters fish encounter layers with different temperatures, salinities, oxygen concentrations and currents varying in direction, and the implications on the behaviour and life history strategy are discussed. We argue that the pearlside cope with the environmental conditions in the northern Benguela region both by adaptive reactions in response to severe environmental events and adapted life history traits. We suggest further field studies aiming at resolving how hypoxia and sulphurous water masses influence the physiology and behaviour of all life stages of M. muelleri.
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3 June, 16:45 (P9 OP5)
A 9-year periodicity in small pelagic fish recruitment from upwelling areas S. Hernández-León Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain. Email:
[email protected]
Recent findings in the development of zooplankton with the lunar cycle in subtropical waters explained a common observation in the literature related to the influence of the lunar cycle on fish maturation and spawning. The observed changes in zooplankton promote periods of enhanced feeding of adult fish and lower mortality in the early planktonic stages of fish. A recently published analysis of the fish catch in the four major upwelling areas showed a pattern of ~9-year periodicity in mortality of sardine and anchovy fish coinciding with the long-term variability in moon illumination. The development of fisheries was related to a 9-year period of low and high mortality and therefore, recruitment should also show a pattern of enhanced values during the lower predatory scenario. Our search through the four main upwelling areas showed periods of increased recruitment for that year during the low predation period in both groups of species. When the standardised data for each group of species was pooled by standardising the date of the longterm lunar cycle, it was observed that sardine and anchovy species showed higher values during the period of low mortality. Thus, a natural variability in recruitment of fish is envisaged and should be considered in order to study the effect of climate on fisheries.
3 June, 17:30 (P9 OP6)
Comparing the influence of oceanographic fronts on interannual changes in the distribution and relative abundance of sardine in the California and southern Benguela Current systems R. Rodríguez-Sánchez1, C. van der Lingen2, M. Manzano3, L. Hutchings2 and H. Villalobos1 1 2 3
Centro Interdisciplinario de Ciencias Marinas (CICIMAR - I.P.N.) La Paz, B.C.S., Mexico. Email:
[email protected] Marine and Coastal Management, Cape Town, South Africa. Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Mexico.
Marked changes in the distribution and relative abundance of sardine Sardinops sagax populations in the California and Southern Benguela Current systems have been reported, with these changes occurring over recent decades during periods of steadily increasing population size in both systems. Such distributional changes may be environmentally-mediated, and this paper assess whether mesoscale frontal activity could be a mechanism underlying latitudinal and longitudinal shifts in sardine distribution in the California and Southern Benguela Current systems, respectively. That the location and occurrence of oceanographic fronts may affect sardine distribution patterns is based on preliminary results from the California Current system (CCS), where the latitudinal distribution of monthly abundance indices of young California sardine seems to follow seasonal changes in advection, suggesting that recruitment is related to the location of the frontal zone where the California Current (CalC) and the inshore California Countercurrent (CcC) converge. Over the period 1980 to 1997 sardine in the CCS showed a progressive northward shift in the location of highest relative abundance, suggesting northward changes in the location of favourable conditions for young sardines along the frontal zone between Baja California and California. We proxied interannual variability along the frontal zone by developing monthly time-series of the frequency of SST fronts in different areas along the California–Baja California coast using the single-image, edge-detection method applied to monthly satellite data from the AVHRR Pathfinder v5, and the relationship between sardine abundance and SST front frequency indices suggests that recruitment increases where optimal front-frequency levels are found and declines where they are suboptimal. Interannual changes in the distribution of sardine along the frontal zone suggest a progressive, interannual increase in northward advection of the CcC following the 1976–1977 regime shift, whereas southward advection via the CalC weakened. We use a similar approach to assess whether the eastward shift in the distribution of Southern Benguela sardine was also environmentally mediated by examining frontal activity data from different areas of the Agulhas Bank, where seasonal and interannual variation in interactions between a major surface boundary current (the westward-flowing Agulhas Current) and an eastward-moving, coastal counter-current also occur. 200
Eastern Boundary Upwelling Ecosystems Symposium
3 June, 17:45 (P9 OP7)
Habitat expansion and contraction in anchovy and sardine populations in EBC and WBC M. Barange1, J. Coetzee2, M. Gutierrez3, K. Hill4, Y. Oozeki5, A. Takasuka5, C. van der Lingen2 and V. Agostini6 GLOBEC IPO, Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, United Kingdom. Email:
[email protected] Marine and Coastal Management, South Africa. 3 Tecnologia de Alimentos (TASA), Peru. 4 NOAA SWFSC, USA. 5 National Research Institute for Fisheries Science, Fisheries Research Agency, Japan. 6 Global Marine Initiative, The Nature Conservancy, USA. 1 2
Small pelagic fish species are economically and ecologically important components of upwelling ecosystems, and contribute approximately a third of the global fish catch. Small pelagic fish species are short lived and fast growing and are characterised by marked fluctuations in their stock size because of their high dependence on highly variable, environmentally-driven, annual recruitment pulses. There is evidence to suggest that these species also display low frequency, multi-decadal productivity cycles, and it has been argued that the productivity cycles of anchovy (Engraulis spp.) and sardine (Sardina spp. and Sardinops spp) alternate. Clarifying the existence of such out-of-phase production cycles has important consequences for sustainable management. Several hypotheses have been proposed to explain out-ofphase abundance fluctuations of these species. Chavez et al. (2003) concluded that the Pacific had a regime oscillation periodicity influencing from atmospheric pressure and ocean climate to alternative food web dynamics, favouring one or another species. Takasuka et al. (2007) proposed a simple "optimal growth temperature" hypothesis, in which anchovy and sardine regime shifts are caused by differential optimal temperatures for growth rates during the early life stages. An alternative hypothesis establishes that such fluctuations must be trophodynamically mediated, caused by competition and adaptation to specific food resources. These hypotheses imply that anchovy and sardine respond in a similar (albeit opposite) manner to physical forcing and thus that they have similar preferred habitat and habitat selection mechanisms. Habitat selection by marine fish is hypothesised to be based on the “ideal free distribution”, according to which habitat choice is based on suitability and geared towards maximising individual fitness. Three basic models have been proposed to describe the relationship between stock size, distributional area and local density under the ideal free distribution: (i) constant density model, where density stays constant and the area covered by the stock varies with abundance; (ii) proportional model, where the area occupied stays constant and local density varies proportionally to abundance; and (iii) basin model, where density and area vary with abundance. If anchovy and sardine are equivalent species demonstrating synchronic abundance fluctuations, their habitat selection should also be equivalent. In this contribution we will investigate the relationship between stock size, density and distributional area for anchovy and sardine stocks in three eastern boundary regions (Humboldt, California and Benguela), and one western boundary region (Japan), looking for density-dependent as well as density-independent patterns in the occupation of space that would provide arguments for and against the possibility of them developing synchronic, alternating biomass fluctuations. Preliminary results suggest that the strategies vary between regions and between species in different regions, but some clear patterns emerge regarding contraction/expansion strategies following fluctuations in stock size.
3 June, 18:00 (P9 OP8)
Does the vertical extent of suitable physical habitat constrain small pelagic fish populations in the Humboldt and Benguela Current upwelling systems? A. Bertrand1,4, A. Chaigneau1, J. Coetzee2, J. Habasque1,4, L. Hutchings2, J. Ledesma3, S. Peraltilla3 and C. van der Lingen2 IRD, Teruel 357, Casilla Postal 18-1209, Miraflores, Lima 18, Peru. Email:
[email protected] Marine and Coastal Management, South Africa. 3 Instituto del Mar del Peru, Peru. 4 IRD, UR097, France. 1 2
Abiotic characteristics such as low dissolved oxygen levels and cold temperatures at the bottom of the upper mixed layer can constrain the habitat (particularly in the vertical domain) of small pelagic fish species in eastern boundary upwelling systems. Data on the abundance and the vertical and horizontal 201
Eastern Boundary Upwelling Ecosystems Symposium distributions of anchovy (Engraulis spp.) and sardine (Sardinops sagax) collected during hydroacoustic surveys over the past 25 years in the Humboldt and Benguela Current systems were compared with vertical profiles of dissolved oxygen and temperature to determine lower tolerance threshold levels of anchovy and sardine to these abiotic parameters. We completed these data with results from laboratory experiments performed to examine the effect of swimming speed and feeding behaviour on sardine and anchovy respiration. Finally we also took into account species-related differences in the vertical extension of the fish schools and/or fish behaviour. The determined thresholds on oxygen and temperature were then applied to available historical profiles (1960-2005) in order to investigate the spatiotemporal variability of the physically-suitable habitat within the two upwelling systems. Temporal changes in the volume of physically suitable habitat are compared to the long term dynamics of anchovy and sardine populations, highlighting the similarities and discrepancies between the Humboldt and Benguela regions. This will enable an assessment of whether alternations between these two small pelagic species may be partly linked to physical habitat constraints.
3 June, 18:15 (P9 OP9)
Why the Peruvian anchovy collapsed and why it recovered again O. Morón1, M. Ñiquen1 and J. Alheit2 1 2
Instituto del Mar del Peru, Esq. Gamarra y Valle s/n, Chucuito,Callao, Callao, Lima, P.O. Box 22, Peru. Email:
[email protected] Leibniz Institute for Baltic Sea Research, Germany.
The Peruvian anchovy (Engraulis ringens), the basis of the largest single species fishery of the world, collapsed around 1971 and recovered again in the mid-1980s. The causes of collapse and recovery have been an enigma since and subject to many speculations. Usually, a combination of overfishing and adverse effects of the 1972/73 El Ñino are made responsible for the failure of the anchoveta fishery. However, anchovy recruitment clearly failed in 1971, before the onset of El Ñino. Based on a suite of longterm hydrographic time series compiled recently, we forward an alternative hypothesis and argue that the anchovy collapse was brought about by a lasting approach of oceanic Subtropical Surface Waters (SSW) towards the Peruvian coast changing substantially the structure of the coastal realm and diminishing to a large extent the typical cold upwelling habitat of the anchovy, the Cold Coastal Waters (CCW). The coastward movement of the SSW was indicated by a slackening of the trade winds, deepening of the thermocline, differential warming of the El Ñino regions and, most importantly, increasing salinity of coastal waters. From the timing of all these physical processes it emerges, that the waters off Peru, and probably off Chile, were dominated by CCW from the beginning of regular oceanographic measurements in the 1960s, a period of cooler SSTs and a shallow thermocline. This environment supported a high biomass of meso-zooplankton (>300 micron) and provided excellent recruitment conditions for the anchovy. The intrusion of SSW beginning in the late 1960s resulted in warmer SSTs and a deeper thermocline. This new “more oceanic” environment caused an entire suite of adverse conditions for the anchovy. Predation on all life stages increased whereas the abundance of one of its most important food sources, large calanoid copepods, decreased, so finally leading to the decline of meso-zooplankton biomass and the crash of the Peruvian anchovy stock in 1971, a combined result of the changing environment and, probably, of the heavy fishing pressure. The now “more oceanic” environment with different “more oceanic” plankton communities, which appears to have been more favourable for sardine recruitment and survival, gave rise to a lasting increase of the sardine (Sardinops sagax) population from about 1970 to the mid-1980s when it started to decrease again to the negligible biomass observed in recent years. In the mid-1980s, trade winds seem to have strengthened again, the thermocline shoaled and salinity in the coastal regions decreased indicating the offshore retreat of SSW. Within a very short period of two years, the anchovy biomass increased to several million metric tons biomass and has supported a large fishery since. Apparently, dynamics of anchovy and sardine in the Humboldt Current ecosystem are governed by long-term physical processes which are very likely associated with basin-wide circulation changes. This new hypothesis to explain the alternation of anchovy and sardine in the Humboldt system will be discussed in the light of alternative hypotheses. 202
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3 June, 18:30 (P9 OP10)
What is driving Cape Hake recruitment in Namibia? How the collapse of small pelagics can affect a demersal stock in a degraded upwelling system J-P. Roux Ministry of Fisheries and Marine Resources, PO Box 394, Luderitz, Namibia. Email:
[email protected]
The trophic web of upwelling ecosystems is characterised by the key position of small pelagic fish in high abundance at mid trophic level. Since the collapse of the small pelagic stocks in the late 1960s and early 1970s, the northern Benguela ecosystem structure has been altered and represents a trophically degraded upwelling system. The Cape hake (Merluccius capensis) recruitment dynamics were studied for the past 14 years using information derived from top predators. This study, together with information on diet composition, comparisons with the same species in a “small-pelagic-rich” system (the southern Benguela) and a simple model reveals that in the absence of small pelagics and subsequent changes in the food web, cannibalistic interactions between successive cohorts of juvenile Cape hakes have been enhanced off Namibia and could be the dominant driving factor of Cape hake recruitment dynamics. Patterns of variability in age-class strengths at about 2 years of age suggest a strong top-down effect between successive hake cohorts resulting in a lower productivity of the hake stock and an amplification of the variability induced by environmental anomalies (e.g. Benguela Niño events). Modelling results suggest that a recovery of the small pelagic stocks off Namibia (sardine and anchovy) is likely to benefit the Cape hake stock in different ways, including an improvement of the hake stock productivity, an increase in average recruitment level, a decrease in recruitment variability and a dampening of the negative effects of environmental anomalies. These results demonstrate a possible strong interaction between the management of small pelagic fish and the dynamics of an important demersal species through alteration of the trophic pathways and highlight the central role of small pelagics in the functioning of an upwelling system like the Benguela. The monitoring and quantification of trophic interactions and process studies to understand the ecological linkages such as the ones suggested above are essential in the development of the scientific basis of an Ecosystem Approach to Fisheries Management.
3 June, 18:45 (P9 OP11)
Fishing effort spatial analysis and its relation to the resources distribution: case of the seiners fleet fishing in the Moroccan Atlantic Sea, between Cap Cantin and Cap Blanc R. Houssa1, A. Lakhnigue1, A. Marhoum1, H.Chfiri2, K.Oakka3, H.Gourich3 and H.Elwazzani4 Institut National de Recherche Halieutique, 2 rue de Tiznit, Casablanca, Morocco. Email:
[email protected] Centre régional de l’INRH à Agadir, Morocco. 3 Centre régional de l’INRH à Laâyoune, Morocco. 4 Centre régional de L’INRH à Dakhla, Morocco. 1 2
The small pelagic fishing activity is very important in Morocco. Nearly 1 million of fish product have been reached in 2006. More than 90% of this production has been realised in the area between Cap Cantin (32°30’N) and Cap Blanc (20°46’N). These resources are exploited by three types of fleet: traditional coastal seiners, modern coastal seiners (RSW: Refrigerated sea water) and pelagic trawlers. 369 active seiners (statistics, 2006) have produced 70% of the total catches unloaded in 8 ports located along a coastline of 1600 km and which are from the North to the south: Safi, Essaouira, Agadir, Sidi Ifni, Tan-tan, Tarfaya, Laâyoune and Dakhla. These seiners are an important dynamic fleet, about 65% have operated from more than one port. This dynamic is expressed by a spatial variability of the exploited area which could be explained, among others, by the spatial distribution of target species. The model FAST (Fishing Activity Simulation Tool) is used, in this study, to chart and quantify by simulation the zones of activity of the fishing fleet. As data input, three variables: depth, distance to fishing area and nominal effort, expressed in hours spent to fish were used (data collected from fishermen in 2006). The small pelagic resources distribution was mapped using abundance index recorded during surveys (R/V DR. Fridjof Nansen, 2005/2006). The overlapping of these zones with those of the spatial distribution of the fishing effort allowed identification ofspatial indexes which were exploited to understand the seiners’ spatial dynamic. The relationship between fishing effort and resources spatial distribution is an important element to understand the fleet mobility. But, the knowledge of fishing strategies and the relation to socio-economic factors would be necessary to complete this analysis and lead to a good management of the fishery. 203
Eastern Boundary Upwelling Ecosystems Symposium
P9 Posters Poster: P9 P1
Population dynamics of the anchovy Engraulis encrasicolus around Larache (NW of Morocco) M. Aksissou and B. El Yazidi Department of Biology, Faculty of Science, PO Box 2121, Tetouan 93002, Morocco. Email:
[email protected]
This work concerns the study of certain characteristics of the dynamics of the populations the anchovy Engraulis encrasicolus in the area of Larache, The sampling was carried out from November 2006 to June 2007. The structure of age was given to leave the reading the otolithes of a sample made up of 516 individuals. The population is dominated by the 3rd-year-class (35,15%) and the 2nd-year-class (32.82%). The size of the anchovy population varies from 9.50 to 16.20 cm and the weight from 5,16 to 29.53 g. The length-weight relationship of anchovy was described by the expression: PT=0,0039 LT3,219 The relationships between total length-standard length is: LS= - 0,4398 + 0,904 LT and that between total Length-fork length is : LF= - 0,3176 + 0,9427 LT The general average of the sex-ratio was slightly in favour of the males with 53.92% during the period of study. Size at first maturity is reached at 13.7 cm for males and 13.8 cm for females. The reproductive period is spread out Mars at June coinciding with the stages of massive development of the gonades. The condition factor reaches a maximum in summer with a means of 0.68 ± 0.06 g/cm3. These data are very interesting in the Moroccan Atlantic fisheries of anchovy in so far as they make it possible to know the biological period of rest and also the minimal sizes of capture for a durable management of this halieutic stock.
Poster: P9 P2
ICES - Working Group on Acoustic and Egg Surveys for Sardine and Anchovy (WGACEGG): fish stock estimation and pelagic habitat characterisation in the European North Eastern Atlantic M. Angélico1, M. Bernal2, Y. Stratoudakis1, P. Beillois3, G. Boyra4, G. Costas5, C. Franco6, D. Garabana5, L. Ibaibarriaga4, M. Iglesias7, M. Jiménez2, A. Lago de Lanzós6, V. Marques1, J. Massé3, M. Millán2, E. Nogueira8, C. Nunes1, J. Pérez5, P. Petitgas3, F. Ramos2, B. Santos5, M. Santos4, A. Silva1, A. Uriarte4 and J. Zwolinski1 INRB/IPIMAR (Instituto de Investigação das Pesca e do Mar), Av. Brasília, Lisboa, 1449-006, Portugal. Email:
[email protected] IEO, Unidad de Cádiz, Universidad de Cádiz, Spain. 3 Institut Français de recherche pour l'exploitation de la mer (IFREMER), Nantes, France. 4 AZTI, Tecnalia - Instituto Tecnológico Pesquero Y Alimentario, Spain. 5 IEO, Centro Oceanográfico de Vigo, Spain. 6 IEO, Madrid, Spain. 7 IEO, Centro Oceanográfico de Baleares, Spain. 8 IEO, Centro Oceanográfico de Gíjon, Spain 1 2
The ICES Working Group on Acoustic and Egg Surveys (WGACEGG) was created in 2005 to coordinate and standardise fishery independent methods for pelagic fish stock estimation in ICES areas VIII and IXa (Brest to Gibraltar). Biotic and environmental characterisations of the pelagic habitat are parallel objectives. The Group joins researchers from fisheries institutes in France (IFREMER), Spain (AZTI, IEO) and Portugal (IPIMAR), in annual meetings and develops research and monitoring related to small pelagic fish and their environment. The Group coordinates Daily Egg Production Method (DEPM) and acoustic surveys directed to the assessment of sardine and anchovy stocks. DEPM surveys for sardine are conducted in the Iberian Peninsula every 3 years in winter/early spring. Anchovy DEPM surveys take place annually in the Bay of Biscay (BB), in late spring, and started recently in the Gulf of Cadiz (GC), in summer. Acoustic 204
Eastern Boundary Upwelling Ecosystems Symposium surveying is carried out each year across the whole area in spring for sardine and in BB and GC in spring/ summer for anchovy. Research surveys for sardine and anchovy juveniles take place in autumn in the main recruitment areas. During the campaigns pelagic community structure and biological information are collected. Plankton sampling is carried out using nets and CUFES and oceanographic parameters are registered in situ (CTF and CTDF), census of marine seabirds and mammals are also conducted. The present poster highlights the major results obtained in the 2007 surveys and discussed in the latest WG meeting. The spring acoustic surveys showed a high diversity of pelagic species; mackerel occupied mainly the northern part of the area, chub mackerel the southern part, horse mackerel and sardine occurred across the whole area and anchovy was located in the BB and in the GC. Acoustically estimated biomass of sardine was within the range for other years in the Iberian waters but one of the lowest in the BB. The population was dominated by the strong 2004 year-class and the age/size composition is also indicative of poor recruitment in the last two years. Anchovy in the BB showed some signals of improvement from the situation in 2005, when the population reached the minimum spawning stock biomass (SSB) value of the time series since the 1980s; i) a slight increase in SSB, ii) an increase in the distribution area and an increase in the proportion of age 1 individuals. Nevertheless, SSB values are still among the lowest of the time series and therefore the population is not yet regarded as recovered.
Poster: P9 P3
Feeding modes switches of Trachurus trachurus to respond to heterogeneity of prey size and density T. Antezana Departamento de Oceanografía, Universidad de Concepción, P.O.Box 4010, Concepción, Chile. Email:
[email protected]
The diet of most Trachurus species is dominated by euphausiids, followed by fish and by a wide variety of planktonic organisms. The rank order of prey may result from an active selection of prey among co-occurring prey, or from an opportunistic behavior of fish, feeding sequentially as prey are encountered. Testing plasticity in prey capture was the main aim of this work. A repertoire of feeding modes, feeding stages and shifts between modes were observed and video recorded in feeding experiments on T. trachurus. Feeding modes fell into three groups: suction feeding, ram feeding and biting which were displayed at distinct conditions of density and size of prey. The most unexpected modes among particle suction were pump filtration and basal filtration. Feeding stages of pre-feeding, feeding and post feeding were characterised by individual’s fish movements and their mouth activity. Switching modes occurred in several directions between feeding modes and as a function of particle size and density. The main trend when decreasing prey size and increasing density: biting……1-particle suction…..basal filtration. The first implication is that an individual fish has the ability to choose from an ample repertoire, the most appropriate feeding mode according to size, density (and probably behavior) of prey to respond to sudden changes in prey availability, as in patchy and transient environments. A second implication is that daily ration and diet composition represent to a great extent the composition and abundance of prey in the environment and its natural changes, rather than prey selectivity.
Poster: P9 P4
Ichthyoplankton transport from the African coast to the Canary Islands: a case study using a high-resolution hydrodynamic model T. Brochier1, E. Mason2, P. Sangrà2 and C. Lett3 1
2 3
IRD, UR ECO-UP, Centre de Recherche Halieutique méditerranéenne et Tropicale, Avenue Jean Monnet, BP 171, 34203 Sète cedex, France. Email:
[email protected] Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain. IRD, UR Geodes, Institut des Systèmes Complexes, France.
The Canary Upwelling system (CUS), located along the northwestern coast of Africa, is one of the four major eastern boundary current systems of the world ocean. One of the particularities of this system is the presence of the Canary Island archipelago, which lies close enough to the continental coast to permit exchange of biological material between the islands and coastal areas. The perturbation by the Canary 205
Eastern Boundary Upwelling Ecosystems Symposium Islands of the southward flowing Canary Current generates turbulence downstream of the archipelago, that acts as a mechanism of ichthyoplankton concentration. Large filaments of upwelled water transport ichthyoplankton from the African neritic zone towards the Canary archipelago. The interaction of these coastal filaments with island-generated cyclonic eddies may constitute a favourable fundamental triad (enrichment, concentration, retention) for a reproductive habitat. In this poster we seek to test and explore these ideas in this complex region, by using an ichthyoplankton transport model in combination with highresolution hydrodynamic model results. We generate a 1.5 km Regional Ocean Modelling System (ROMS) solution of the circulation over an area covering the Canary archipelago and the coastal upwelling, from 23°to 32°N. The simulation is climatologically forced at the surface (heat fluxes, precipitation and wind stress), but reproduces mesoscale features, mainly filaments and eddies and their interactions, which have good qualitative agreement with observations. Boundary forcing (temperature, salinity and velocity) was provided from a parent ROMS simulation, itself forced by a monthly climatology. The simulation lasts two years, providing ample output (velocity fields) for use within the ichthyoplankton transport model. A Lagragian individual based model (IBM), Ichthyop, is used to track the advection of virtual ichthyoplankton, from known anchovy and sardine spawning areas within the coastal upwelling to the Canary Islands. We designed numerical experiments to measure the frequency of particle transport from the African shelf to the coastal waters around the island of Gran Canaria, and compare it with the signal of filament presence. Moreover, we calculate the journey time for particles released over the continental shelf to reach the island of Gran Canaria, as well as the residence time of the particles along their trajectories. Finally, we discuss our results in the light of field observations of fish eggs and larvae in CUS waters.
Poster: P9 P5
The recruitment rate in anchoveta (Engraulis ringens) and climatic regimes off Peru S.M. Cahuin1, L. Cubillos2 and R. Escribano3 Programa de Doctorado en Oceanografía, Universidad de Concepción, Barrio Universitario s/n, Concepción, 8340422, Chile. Email:
[email protected] 2 Laboratorio de Evaluación de Poblaciones Marinas (EPOMAR), Universidad de Concepción, Chile. 3 FONDAP-COPAS, Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Chile. 1
The reproductive rate of anchoveta off Peru was used to identify regimes by considering that reproductive success responds faster to environmental changes. Three regimes were identified: 1) unfavourable, for the periods 1975-1979, 1981-1983, 1987, and 1991;2) transitional, for the periods 1972-1974, 1980, 19841986, 1989-1990, and 1997; and 3) favorable, for the periods 1963-1971, 1988, 1992-1996, and 19981999. These regimes were characterised by a common intercept and significantly different slopes in the recruitment rate when plotted against the spawning stock biomass, which suggest the hypothesis that these different regimes are affecting the density-dependent effects on recruitment of the Peruvian anchoveta. The favourable (unfavourable) regime was characterised by higher (lower) zooplankton volumes and cold (warm) waters, while the transitional regime was either warm or cold. Zooplankton volume and sea surface temperature do not explained the interannual fluctuations in recruitment. However, a significant non linear relationship between recruitment rate, spawning stock biomass and zooplankton volume was detected with Generalized Additive Model. It is concluded that climatic regimes are affecting the density-dependent effects on recruitment of anchoveta rather than recruitment itself. Probably, the mechanisms involved are associated to changes in the carrying capacity of the spawning habitat of anchoveta.
Poster: P9 P6
Annual cycle of pelagic fish off Gran Canaria Island P. Caldentey, A. Barrera and S. Hernández-León Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017. Las Palmas de Gran Canaria, Spain. Email:
[email protected]
Length, weight and the gonodosomatic index of pelagic fish were studied from samples (2,341 specimens) collected on board commercial purse-seiners during the annual cycle (from February 2006 to February 2007) in the vicinity of Arguineguín, Gran Canaria. The species studied were Scomber colias (atlantic chub mackerel), Trachurus picturatus (blue jack mackerel), Sardinella aurita (round sardinella) and Sardina 206
Eastern Boundary Upwelling Ecosystems Symposium pilchardus (pilchard, sardine). Total length of chub mackerel ranged between 12 and 37 cm. The breeding season was observed during the winter months, especially in January and February. For the blue jack mackerel, total length ranged between 13 and 30 cm and its reproductive period could not be established. The total length of round sardinella ranged between 9 and 30 cm and its reproductive period was observed throughout the year. The pilchard was found very scarce during the annual cycle and only juvenile specimens were captured. Total length ranged between 10 and 13 cm and its reproductive period was impossible to establish because of the shortage of specimens collected. The presence of young specimens of S. pilchardus and the transport of fish larvae of this species from the upwelling are will be discussed.
Poster: P9 P7
Relationship between genetic structure and ichthyologic aspect on Sardina pilchardus populations in the north western Africa coasts M. Chlaida1, O. Ettahiri1, S. Planes2, H. Jaziri3, S. Kifani1 and S. Ben cherifi1 Institut National de Recherche Halieutique, 2 Rue de Tiznit, Casablanca, 20000, Morocco. Email:
[email protected] EPHE (Ecole Pratique des Hautes Etudes), C.R.I.O.B.E, UMS 2978 CNRS- EPHE, Université de Perpignan, France. 3 Faculté des Sciences de Rabat, Morocco. 1 2
To study the genetic structure of sardine population, we analysed by allozymic markers fourteen samples of sardina pilchardus collected in the Moroccan coasts during the species spawning season (Winter 2004). The results show in the area an important genetic break and a significant genetic difference between two large sardine populations (Fst= 0.205). The first population is located at the south of Agadir bay (30°48’N) and extending till Cadis Golf (36°43.2'N). The second population is distributed from Sidi Ifni (29°12’N) till the southern limit of the species distribution in Mauritania (19°03’N). The same genetic method was applied to analyse another batch of samples gathered during the species feeding season (summer 2006). The results show that the species structuring in two groups is globally respected (Fst= 0.132) and that the difference between the tow seasons relates to only the position of the barrier between the tow populations .Indeed, this barrier occurring in winter between Sidi Ifni and Agadir, moves in the north of Tarfaya (28°08’10”N) in summer. This displacement of the barrier between the two populations would be consequent of a genetic migration during the winter season; this was confirmed here by the confrontation of the results in the sardine reproduction strategy along the Moroccan coasts. In fact, the sardine reproduction in winter extends from Agadir area till Lagouira ( 20°50‘00N); this would testify to a possible reproduction of sardine along the coast (Agadir -Lagouira), and would induce a spreading out of southern stock towards the south. On the other hand the situation changed in summer when the reproduction potential was maintained in the south of Tarfaya–Boujdor (28°13'N- 25°59’N) region; this very weak potential and even absent in the north of this border may generated a concentration of the stock in the south of Tarfaya. However, the genetic migration cannot solely explain this situation. The North South migration, called trophic migration, carried out during the summer can also bring some information: the spreading out towards the south of the northern stock during the summer would be the consequence of a trophic richness which is generated by the upwelling phenomenon which intensifies during this period between Safi and Tarfaya (32°28'N-28°13'N).
Poster: P9 P8
Spawning and daily egg production for common sardine (Strangomera bentincki) and anchovy (Engraulis ringens) off central southern Chile L. Cubillos1, G. Claramunt3, K. Riquelme1, C. Castillo-Jordán1 and L. Castro2 Laboratorio de Evaluación de Poblaciones Marinas (EPOMAR), Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. Email:
[email protected] 2 Laboratorio de Oceanografía Pesquera y Ecología Larval (LOPEL), Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Chile. 3 Departamento de Ciencias del Mar, Universidad Arturo Prat, Chile. 1
Annual changes in the spawning patterns and in the daily egg production are analysed for the common sardine and anchovy stocks distributed in the central-south area off Chile (33ºS-41º30S). The objective was to study the main effects of geographic (latitude, longitude), bottom depth and sea surface semperature 207
Eastern Boundary Upwelling Ecosystems Symposium on the realised spawning habitat and daily egg production of common sardine and anchovy on the basis of four surveys carried out during the main spawning peak (August-September) off central-southern Chile. Staged egg frequencies data were used to compute daily cohort densities by using an ageing method based on a multinomial model fitted to incubation experiment data and on a prior probability density function of spawning time. Daily cohort egg numbers were fitted by means of a generalised additive model (GAM) with negative binomial error distribution, in which the daily egg production were fitted as smooth functions of spatial and physical variables (bottom depth and sea surface temperature). Recurrent sites of spawning were observed during the study period, with the bulk of the spawning of both species characterised by a coastal distribution within the first 20 nautical miles, and following the inner zone delimited by the 100 m bottom depth. The daily egg production rate (P0) based on a spatial model was similar to those estimated on the basis of a single mortality curve, and fluctuated between 4.1 to 79.4 x 1011 eggs in anchovy, and between 7.5 and 28 x1011 eggs for common sardine. Sea surface temperature and bottom depth, along with geographic location, explained the total egg density as well as the daily egg production. The coastal distribution of the spawning can be related to the oceanographic conditions occurring during the transition from winter to spring (southern hemisphere), which are characterised by the alternation between northerly and southerly winds, the coastal shape, and the bottom depth. It is concluded that these factors are interacting to produce enrichment, concentration and retention of eggs in coastal zones in the study area.
Poster: P9 P9
Spatio-temporal variability in the realised spawning habitat of anchovy (Engraulis ringens) off northern Chile L. Cubillos1, G. Claramunt2, C. Castillo-Jordán1, R. Serra3 and M. Braun3 Laboratorio de Evaluación de Poblaciones Marinas (EPOMAR), Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. Email:
[email protected] 2 Departamento de Ciencias del Mar, Universidad Arturo Prat, Chile. 3 Instituto de Fomento Pesquero, Valparaíso, Chile. 1
The realised spawning habitat of anchovy (Engraulis ringens) off northern Chile, defined as the region where fish actually spawn in a given year at a given time, display larger year-to-year fluctuations. In this paper, we describe the interannual changes in the spatial distribution of spawning of anchovy during 12 surveys carried out during 1992–2006. The objective was to identify recurrent (or refuge) sites where spawning is observed each year with low variability from alternative sites where the probability of spawning varies greatly from year to year. We used presence-absence data to avoid the influence of egg density. Presence (coded one) was considered when egg density was greater than 1 egg/0.05 m2, otherwise the data were coded zero for absence. Experimental variograms were computed on binary-transformed data, and the exponential model was satisfactory to explain the annual changes in the spatial structure and the extent of the spawning by kriging. The result of kriging is a map of the probability of egg presence for each year. In spite of the high interannual variability observed in the realised spawning habitat, an average map of probability of egg presence revealed that the spawning habitat of anchovy is confined to the coastal waters (probability higher than 60%). Indeed, four coastal zones reached the higher average probabilities (> 60%): a) off Arica (18°20’S), b) south of Iquique or nearby the Loa river mouth (from 21°S to 22°S), c) Mejillones bay and d) Antofagasta. Also, one zone of importance was located offshore (22°S to 22°30’S), but with great variability from year to year. The sill of the variograms was explained by an index of patchiness, which was based on the dispersion parameter of the negative binomial distribution of egg density. The lowest range of the variograms occurred in 1997, which was characterised to be the warmest year of the time-series and associated to the El Niño event of 1997-98. Nevertheless, it is probable that the observed spatial variability in the realised spawning habitat of anchovy off northern Chile can be related to adult population size and structure as well as density-dependent processes. 208
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Poster: P9 P10
The Effect of environmental changes on the recruitment success of Moroccan sardine (Central Atlantic area) H. EL Ouizgani and Y. Snaiki Laboratoire d’océanographie et Limnologie, Université IBN ZOHR, Faculté des sciences, B.P 8106, Agadir, Morocco. Email:
[email protected]
The aim of this study was to determine how climatic (NAO, December through March), oceanographic (upwelling intensity, turbulence and SST) and biotic (adult abundance) factors affect recruitment success of Sardina pilchardus off the central coast of Morocco. Catch per unit effort at age 0+1 from 1983 to 2001 were used as an indicator of sardine recruitment success. In the recent past, it has been put forward that recruitment of the North Atlantic sardine could be related to the North Atlantic Oscillation (NAO). In this document, the biological processes behind the NAO/recruitment relationship are further investigated. Then, the possible relationship between the central Moroccan sardine recruitment was investigated. The linear relationship appeared to be only due to the low frequency signal. The highest catches of the sardine (Sardina pilchardus. Walb 1782) were taken from the southern part of the Moroccan Atlantic coast (Zone C) and Central part (zone A and B). Recent catches from the central coast have shown an important decline. Given the dependence of the fishery in this area on the strength of the recruitment, this paper analyses the relationship between recruitment and both meso-scale (local) and large-scale processes. The meso-scale processes include indices of coastal upwelling, sea surface temperature and turbulence, while large-scale physical forcing includes indices of the North Atlantic Oscillation (NAO).
Poster: P9 P11
Length-weight relationships and reproduction of small and medium pelagic fish species in the Canary Island Waters I. Herrera Rivero1, A. Barrera Luján2 and S. Hernández-León1 Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, Facultad Ciencias del Mar, Laboratorio Oceanografía Biológica, 35017, Las Palmas de Gran Canaria, Spain. Email:
[email protected] 2 Instituto Canario de Ciencias Marinas, Spain. 1
The annual cycle of pelagic fishes Scomber colias, Trachurus picturatus, Sardinella aurita and Sardina pilchardus around the island of Gran Canaria (Canary Islands) was studied from February 2005 to January 2006. We analysed 1952 specimens of Atlantic chub mackerel (Scomber colias) ranging from 8-40.2 cm in total length (TL) and 8.5-641 grams in weight (W). Its reproductive period was short and extended from January to February. The length/weight relationships for every species showed a positive allometry. A total of 398 specimens of T. picturatus (blue jack mackerel) in the size range of 8-30 cm TL, 5-234 grams in weight, were also studied. Its reproductive period extended through the winter months with a peak in March. S. aurita (round sardinella) showed a size range of 6-31 cm TL, 2-254 grams in weight (401 specimens). This species showed a small variability in the gonadosomatic index (IGS), which was constant from December to July, decreasing from August to November. S. pilchardus (European pilchard) appeared in a very low number (only 33 individuals captured) in the size range of 8.5-20.5 cm TL, 5.5-76 grams in weight. It is remarkable that Sardina pilchardus did not show clear evidence of reproducing in the Canary Archipelago, since during the annual cycle studied low numbers of specimens were caught and those always showed the gonads not developed. The other species seemed to be positively reproducing around the islands. Compared to previous studies during the 80s and 90s our results suggest a replacement of S. pilchardus by S. aurita.
Poster: P9 P12
Spatio-temporal variability analysis of two fish stocks: sardine and sardinella in the eastern central Atlantic, from Cape Juby to Cape Blanc R. Houssa, S. Kifani and A. Lakhnigue Institut National de Recherche Halieutique, 2 Rue de Tiznit, Casablanca, Morocco. Email:
[email protected]
Based on a series of historical spatial observations (1971 - 2005) from commercial fishing and acoustic surveys of small pelagic resources in the eastern central Atlantic area, from Cape Juby to Cape Blanc, this work is trying to discover patterns of geographic variation of two species: sardine (Sardina pilchardus) 209
Eastern Boundary Upwelling Ecosystems Symposium and sardinella (Sardinella spp.). Using GIS technologies, particulary the centres of gravity, we will identify specifically the change over time in the position of the centre of gravity of the abundance areas of these two species whose boundaries distribution fluctuate around Cape Blanc. The results show trends in movement of the abundance areas, to the south for the northern species: sardine and to the north for the southern species: sardinella.
Poster: P9 P13
Synthesis on early life history of pelagic fish species (Sardinops sagax, Engraulis encrasicolus, Trachurus capensis) in the northern Benguela during the early 2000s A. Kreiner1, E. Stenevik2 and S. Sundby2 1 2
NatMIRC, P.O. Box 912, Swakopmund, Namibia. Email:
[email protected] Institute of Marine Research, Norway.
Early life history studies of pelagic fish in the northern Benguela upwelling system were mainly conducted during the 1970s and 1980s, when the system was in a high upwelling regime and stocks were in a much healthier condition than in the 2000s. Studies done during the 1990s suggested that early life history strategies of some pelagic fish in the northern Benguela have changed. Under the BENEFIT programme, annual ichthyoplankton surveys were conducted onboard the Norwegian research vessel “Dr. Fridtjof Nansen” from 2002 to 2005. During these surveys eggs and larvae of pelagic fish were collected using a Hydrobios® Multinet and environmental data was sampled using a Seabird 911 CTD. Although high interannual variability in temperature and dissolved oxygen concentration in the survey area was observed, no major environmental anomaly (e.g. Benguela Niño) was observed. Temperatures measured at 10 m depth were lowest in 2005 and warmest during 2003. During 2002, 2003 and 2004 the central areas of the Namibian coast were well ventilated. In 2002 areas with low oxygenated waters were observed in the north, while in 2005 water with oxygen concentrations of less than 3ml l-1 at 10m depth were distributed far offshore in the area off Walvis Bay (23°S), limiting the area of suitable spawning habitat for pelagic fish for at least some time during the spawning season. During all years under study, eggs and larvae of anchovy (Engraulis encrasicolus) were found in low number and exclusively north of 20°30’S. In 2002 horse mackerel (Trachurus capensis) eggs were distributed north of 20°30’S while in 2004 and 2005 horse mackerel eggs were found along the entire central Namibian coast. Horse mackerel larvae were found mainly north of 21°S except in 2003 when larvae were found from 23°S northwards. The main areas of sardine (Sardinops sagax) egg distribution were between 22°S and 23°S and between 20°S and 21°S. During 2004 and 2005 smaller amounts of eggs were also found further north of these areas. Sardine larvae were generally distributed slightly further north than the eggs, with no larvae found in the area off Walvis Bay in 2005. The vertical migration pattern was also investigated. Both anchovy and sardine larvae had a type II vertical migration pattern being higher up in the water column during daytime than during night time. This means that the larvae spend at least some of their time below the offshore moving Ekman layer which in this area is about 20 m thick. Most anchovy larvae had a filled swimbladder during night time and empty swimbladders during daytime. Spawning and successful hatching and development of larvae of all three species seems to be partly dependent on favourable concentrations of dissolved oxygen in spawning areas during time of spawning. The spawning season during early 2005, was characterised by low oxygenated waters and despite a large number of sardine and horse mackerel eggs found in that area few larvae were found, suggesting high mortality rates. Recruitment into the fishery from the 2004/2005 spawning season was poor for both species.
Poster: P9 P14
Ekman transport influence on the spatial distribution of anchovy catch off northern Chile (18º-32ºS) during 2006 J. Letelier, F. Espíndola and M. Braun Instituto de Fomento Pesquero, Av. Blanco Encalada 839, Valparaiso, V region, 2340000, Chile. Email:
[email protected]
The bio-oceanographic conditions from the I to IV regions of Chile were used to explain the geographic location of the industrial anchovy catch (Engraulis ringens) off northern Chile (18°-32°S). Weekly satellite information of the wind, (Quikscat) to get the oceanographic variability in a range of 20 km from the shore 210
Eastern Boundary Upwelling Ecosystems Symposium was used. The Ekman transport from the wind component along the coast was used. The results showed a variable distribution of the catches, decreasing at high latitudes, reaching a minimum (< 500 ton) between 23°S and 24°S. From 24.2°S to 26°S the industrial activity disappears, but the fishing activity starts again at the 26°S increasing between the 29.2°S and 30.5°S, where the catches exceeded 3000 ton. Otherwise, the perpendicular transport to the shore conducted by the wind, enhances with latitude, reaching a maximum (>1250 m3/s) between the 28°S and 31°S. This event is interrupted by a decrease of the transport between the 29°S and 30°S. Another relative minimum at the 26.2°S and the 20.5°S was observed. The Ekman transport minimum coincides with an increase of industrial anchovy catch. The maximum perpendicular transport to the shore is associated with the decrease and even with the disappearance of the industrial fishing activity. The spatial distribution of the catches and the Ekman transport show a spatial coincidence between the minimum transport values and the anchovy catch locations, concentrated from January to July and from October to December. Even though part of the fishing activity was made around the 27° S and the 29°S, the highest percentage of tow was located northwards 24°S. The Ekman transport shows a meridional variability related to the wind regional pattern and to the coastline shape in the north of Chile. This transport average intensity pattern shows a spatial distribution inverse to 2006 catches.
Poster: P9 P15
Upwelling and upwelling front influence on the spatial distribution of jack mackerel and anchovy off northern of Chile (18º-24ºS) J. Letelier1, J. Cordova1, H. Reyes1, N. Ramirez2 and V. Valenzuela1 1 2
Instituto de Fomento Pesquero, Av. Blanco Encalada 839, Valparaiso, V region, 2340000, Chile. Email:
[email protected] Escuela de Oceanografía, Pontificia universidad Católica de Valparaíso, Chile.
From November to December of 2006 a hydroacoustic survey “Evaluacion Hidroacustica de Jurel en la región oceanica de la I y II region de Chile (FIP 2006-08) was carried out. Its objective was to make the hydroacoustic prospection of jack mackerel (Trachurus murphy) and other pelagic species such anchovy (Engraulis ringens) off northern Chile (18°S-24°S). The area was covered by 14 oceanographic transects perpendicular to the shore, where 139 stations were distributed. Temperature and salinity in the water column from the surface to the 600 m of depth were recorded. The results show a low temperature water coastal band (<19°C) limited by a front defined by an intense gradient of temperature (0.08° a 0.1° C/km) and density (0.01° [kg/m3]/km). The cold and thicker water band showed a good spatial coincidence with the anchovy distribution, which was limited by the front, especially westward. The front also restricts the spatial distribution of the eufausidos westward, whereas the jack mackerel was located westward from the adjacent area to the front. The anchovy was found concentrated in just one point on the oceanic zone located in the 72°W off Mejillones. At this point a thermal gradient was also found, even weaker than the coastal gradient. The frontal zone, which involves from the coast to the isotherm location of 19.5° C, was characterised by a sudden temperature decrease and also by higher water densities than the oceanic area. This was produced by the coastal upwelling, because the coldest superficial water replaced the superficial waters, displaced to the west because of the wind effect, which predominated during the survey. The results of this project, as well as in previous experiments, show that the upwelling coastal band and the upwelling front along the coast are very important in the history of life of both species, and in the interaction of the anchovy and the jack mackerel in the north of Chile.
Poster: P9 P16
Environment effects on the dynamics of exploitation of the coastal pelagic resources for the north west Africa (between 12° and 26°N) E. Mohamed Mahmoud, B. Hamady and M. Sidi Cheikh PNBA AV. Gamal Abdel Nasser, BP: 5355, Nouakchott, Town Center, 1234, Mauritania. Email:
[email protected]
The fishery of pelagic resources in the coastal areas of north west Africa is multispecific with national fleets and predominant foreign fleets at long-range action. The biomass and catch of coastal pelagic resources of high seasonal, interannual and interdecennial fluctuations due to changes in the ways of access of fishing fleets to the coastal countries EEZs, but also to changes in the area's hydroclimatic conditions. For each 211
Eastern Boundary Upwelling Ecosystems Symposium area, hydroclimatic indicators (average temperature, wind average, the average index of upwelling) were correlated with the indicators of coastal pelagic resource distribution (center of gravity, inertia, catches and biomass). A multivariate analysis of type GLM has shown that the temperature was the most significant factor in determing the distribution of these resources.
Poster: P9 P17
Growth and reproduction of Engraulis encrasicolus at the bay of Agadir, Morocco M. El hafa Université Ibn Zohr Faculté des Sciences Agadir, Departement de Biologie Faculté des Sciences, B.P. 8106 Cité Dakhla Agadir, Agadir, 80000, Morocco. Email:
[email protected]
The study treats some aspects of the biology of the anchovy Engraulis encrasicolus L 1758 landed from Agadir bay. Age and growth was studied by a direct method, based on the estimates of both age and growth from counting annual otolith rings. The indirect method named ELFAN1 (electronic analysis of frequency length) is based on the analysis of size distribution frequencies. The growth’s model used for adjustment of the anchovy parameters is the Van Bertalanffy’s model, written as follows: Males L (T) = 163,5 [1 - exp (- 1,02 (t+1,32))] Females L (T) = 168,25 [1-exp (- 0,88 (t+1,35))] All combined Sex is equal to L (T) = 165,40 [1 - exp (- 1,14 (t+1,01)) ] The (Phi)’ test (Munro and Pauly, 1984) is used to compare our parameters with other studies results. The relative growth was expressed by the relation size-weight (W = a.L B) and a, B coefficients were respectively estimated as a=0.0078 and B=2.942. This result shows an isometric growth. The study of the sex-ratio highlighted the predominance of the females (54, 46%) for the big sizes. The Gonadosomatic index shows a spawning period which is spreading from early spring to the end of the summer, with a maximum in mid July.
Poster: P9 P18
Nycthemeral behavior of Pacific sardine (Sardinops sagax) and consequences on industrial fishery fleet strategy in the Gulf of California M. Nevárez Martínez1, J. Levenez2 and J. Santos Molina1 Instituto Nacional de la Pesca – Unidad Guaymas, Calle 20 Sur No. 605, Col. Centro, CP 85400, Guaymas, Sonora, Mexico. Email:
[email protected] 2 Researcher of the US004, IRD, in retreat from 01/07/2007. 1
The Gulf of California is extremely rich ecological area, supporting an industrial fishery of Pacific sardine (Sardinops sagax) landing more than 250,000 ton per year. The abundance of sardine is closely related to the variability of the upwelling index. A poor upwelling in the early 90th induce a severe collapse for the sardine fishery industry of the State of Sonora. The particularity of the fishery activity (purse seiners) was to maintain a height percentage of overall catches during the night, meaning that the sardines stayed in dense schools during this period. Using data obtained in December 2007 during day and night in the middle of the purse seiners activity area, we can have morphological and energetical characteristics of the same schools of sardines during an nycthemeral period. The results showed that the original behavior of pacific sardines produces a high degree of capturability during the night period. A possible bias due to greater escapement behaviour in the front of the research vessel is discussed. 212
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Poster: P9 P19
Biological interactions between anchovies and sardines in Peruvian waters M. Ñiquen, C. García and C. Peña Department of Pelagic Resources, IMARPE, Esq. Gamarra y Valle s/n, Chucuito – Callao, Callao, Lima, P.O. Box 22 Peru. Email:
[email protected]
In Peruvian waters, the presence of cold water masses and important upwelling areas allow the development of large populations of anchovy (Engraulis ringens) and sardine (Sardinops sagax). These species show biological interactions, mainly in their distribution and abundance, but most authors concentrate on the total biomass and do not discriminated fish size or age groups when studying these interactions. Data used in this work came from the monitoring program based on observers onboard (Log book Program) of the pelagic resources performed by the Instituto del Mar del Peru (IMARPE) since 1996. In particular we used size structure and spatial distribution of anchovy and sardines in the northern-central area off Peru. The analysis of catch per set (or throw) of the net of the purse-seine fisheries between 1996 and 2007 shows that there was a direct interaction between the two species only in 1998, when they were caught in the same set. Based on the 1998 data, three cases were considered: a) b) c)
sets with anchoveta only sets with both anchoveta and sardine sets with only sardine
In situation a) the size frequency distribution of total fish length was unimodal around 14 cm. In b) the distribution range of the two species was located between 10 and 20 cm, with a common modal size around 13-14 cm. In c) the size distribution of sardine was bimodal, with the main mode around 20 cm and the secondary mode around 15 cm. Refining this analysis by latitudinal sub-division shows that the modal sizes of the two species were closer from each other (13-15 cm) in mixed-species set from the Northen region than in mixed sets from the Central region (13-17 cm). Furthermore, the sets with sardine only display a gradient of size according to the distance from the cost, with larger fish size offshore than inshore. From these results we infer that the direct interaction between anchoveta and sardine occur only in a given size range interval. We suppose that at this stage the competition between the two species is a key factor for the abundance of the species during the following years. After this period of intense competition the two species live separately and their abundance will depend on other factors.
Poster: P9 P20
Substitution of Sardine (Sardina pilchardus) for Round sardinella (Sardinella aurita) in the Canary Islands waters M. Santamaría1, J. González1, L. J. López Abellán1, A. Barrera2 and E. Balguerías1 IEO, Centro Oceanográfico de Canarias, Avenida 3 de mayo – Edificio Sanahuja, 38005 Santa Cruz de Tenerife, Canary Islands, Spain. Email:
[email protected] 2 Instituto Canario de Ciencias Marinas, Canary Islands, Spain. 1
Traditionally, sardine (Sardina pilchardus) has been the second most important small pelagic species caught around the Canary Islands while round sardinella (Sardinella aurita) was an accessory species. However, since the 90s this situation has changed and sardine is currently less abundant than round sardinella, and is very scarce in some islands (e.g. 3 092 kg of sardine and 106 133 kg of round Sardinella were caught in Gran Canaria during 2005-2006). Satellite–derived sea–surface temperature (SST) and oscillations of SST anomalies data from 1982 to 2006 were used to detect changes in the oceanographic conditions. In 1995 a temperature increase was observed coinciding with a shift of the upwelling regime intensity off the northwest African coast, reaching a maximum in 1997 that was probably more favourable for round sardinella than for sardine. The monthly evolution of catches in the north and south zones of Tenerife and Gran Canaria during 2005 and 2006 were analysed. It was observed that temperature stability could be more favourable for both sardine and round sardinella than for the other small pelagic species. The S. aurita / S. pilchardus catches in NW Africa and the estimated biomass (1990-2006) do not point to the African connection as the origin of this situation, at least as a direct cause. Some considerations concerning the species substitution process are presented. 213
Eastern Boundary Upwelling Ecosystems Symposium
Poster: P9 P21
Maturity and spawning of some small pelagic fishes in the Canary Islands related to SST conditions M. Santamaría1, J. González1, L.J. López Abellán1, A. Barrera2, E. Balguerías1, M.E. Quintero1, J. Díaz Cordero1, C. López1, C. Presas1 and V. Duque1 IEO, Centro Oceanográfico de Canarias, Avenida 3 de mayo – Edificio Sanahuja, 38005 Santa Cruz de Tenerife, Canary Islands, Spain. Email:
[email protected] 2 Instituto Canario de Ciencias Marinas, Canary Islands, Spain. 1
In order to detect the maturity and spawning season, qualitative (% maturity stages) and quantitative (Gonadosomatic Index) analyses on mackerel (Scomber japonicus), round sardinella (Sardinella aurita) and sardine (Sardina pilchardus) off Tenerife and Gran Canaria (Canary Islands) were made (2005 and 2006). This information was analysed with monthly mean value of satellite–derived sea–surface temperature (SST) and oscillations of SST anomalies data for 2005 and 2006. The spawning of mackerel occured in the first quarter of the year when monthly values of SST were less than 20ºC but most of the individuals were in post-spawning and resting stages. The reproduction season of round sardinella extends throughout the year with the exception of the third quarter. In this spatial-temporal analysis no seasonal spawning peaks were found. In relation to the sardine, only a small proportion of individuals showed developing and spawning stage in the first quarter of the year. On the other hand, only in April 2005 were some sardines greater than 19 cm total length (size at massive maturation) observed. The increase of SST values in the Canary waters in the last years in relation to the optimum spawning temperatures determined for all northwest African regions (16ºC-18ºC) could have induced the migration of that species towards colder waters for spawning. In general, the spawning of these small pelagic species around the Canary Islands showed very low intensity during that period. It is likely that spawning migration towards the NW African coast related to optimal oceanographic conditions could occur.
Poster: P9 P22
Characterising and comparing the spawning habitats of sardine and anchovy in the Northern Benguela region B. Tjizoo1, C. Van der Lingen2, L. Drapeau3, C. Moloney4 and A. Kreiner1 National Marine Information and Research Center, Swakopmund, Namibia. Email:
[email protected] Offshore Resources, Marine and coastal Management, South Africa. 3 IRD, France. 4 Zoology Department and Marine Research Institute, University of Cape Town, South Africa. 1 2
Spawning habitats of sardine and anchovy in eastern boundary current systems are characterised in an attempt to understand the fluctuations observed in their abundance. Spawning habitats in northern Benguela, as in other eastern boundary systems, were characterised by investigating the relation between egg abundance and environmental data collected through two different survey programmes; SWAPEL (1978 – 1985) Nansen (1999 – 2004) surveys, using single factor quotient analysis and temperature-salinity (T-S) plots. Anchovy was found to be less specific than sardine with respect to SST, salinity and oxygen, whereas sardine was less specific than anchovy with respect to bottom depth during the SWAPEL surveys. During the Nansen surveys, sardine was found to be less specific than anchovy with respect to all the environmental variables. Temperature-salinity diagrams showed that anchovy was distributed over a broader range of water masses than sardine during the SWAPEL surveys, whereas the reverse was found during the Nansen surveys. Sardine appears to be better adapted than anchovy because it is better able to vary its spawning habitats. Anchovy might maximise spawning success by timing spawning activities to limit detrimental environmental effects on developmental stages. The spatial structure in egg distributions and variability in the location of spawning centers were explored with experimental variograms to assess spawning behaviour within the spawning habitats of the two species. No coherent spatial structure in egg distributions was found for either of the two species during the SWAPEL surveys (1978 - 1985). This could be a result of the survey sampling strategies, which resulted in increased variability at short distance and reduced variability over long distances. The spawning centers for both species occurred in the area north of 220S during the two surveys periods when centroids were computed. The current low biomass of anchovy and sardine requires adaptive management strategy that permits populations growth, in order to take advantage of vast volume of suitable spawning habitats and allow the quantification of spatial distribution. 214
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P11
The role of top predators and their use as ecosystems indicators
4 June, 10:15 (P11 KNS)
Perception vs reality: the importance of top predators in a seasonal upwelling system J. Parrish University of Washington, Box 355020, 1122 NE Boat St. Seattle, WA, 98195-5020, USA. Email:
[email protected]
Marine birds are highly abundant top predators in coastal communities, and particularly in eastern boundary current upwelling systems. As long-lived, delayed maturity, low fecundity piscivores, seabirds possess both life history and natural history characteristics allowing them to buffer bottom-up changes telescoped through the ecosystem. Studies across the major upwelling systems indicate that seabirds respond to both synoptic and local scales, ranging from interdecadal, basinwide forcing to event scale (3-5 day), centralplace shifts in realised production. As indicators of change, both fluctuating and chronic, seabirds provide a ready platform, in part because of their relative visibility and high numbers, as well as because across the diversity of species most habitats and prey types are represented. However, the degree to which shifts in system production translate into either demographic (i.e., survival, fecundity) or distribution and abundance, is a complex interaction between ecological thresholds presented by shifting environmental factors, and the behavioral response of the birds in attempting to accommodate those shifts. Evidence from across these systems suggests that the within-system diversity of seabirds (an evolutionary and ecological response) mirrors the frequency of environmental perturbations. Increases in prey diversity, evident – for instance – along a north-south gradient in the California Current system, may also correspond to increased ability to buffer change, as seabirds switch across multiple prey types (an ecological and behavioral response).
4 June, 10:45 (P11 OP1)
Composition and at-sea distribution of the seabird community in the Peruvian Humboldt Current system, 1998 – 2006 L. Alza1, G. Swartzman2 and L. Vásquez1 1 2
Instituto del Mar del Peru, Esq. Gamarra y Gral. Valle s/n. Chucuito, Callao. Peru. Email:
[email protected] University of Washington, School of Aquatic and Fisheries Science, USA.
The Peruvian Humboldt Current system supports a large number of seabird species that congregate to feed. In seabirds, foraging behaviour is the most important process determining their presence and distribution at sea. The intensity of the Peruvian upwelling system varies seasonally, being weak during the austral summer and strongest in winter. As a strategy to avoid a decrease in food availability, seabirds may change certain foraging parameters, such as range and aggregation behaviour. However, some environmental variables that affect their distribution and reproduction can not be compensated for, such as El Niño events. The objective of this study was to describe the composition and distribution of the seabird community within 321 km off the coast of Peruin relation to season, physical variables (latitude and water depth) and distance to the coast. Seabirds were classified according to resident (endemic and non-endemic) or migrant (northern or southern) groups. Feeding method, foraging strategy, diet and breeding habits were also considered. Data were collected during 14 pelagic cruises, summer-spring, from 1998-2006. Transect lengths ranged from 3 to 178 km (summer) and 3 at 321 km (spring). To analyse the relationship between seabird groups and independent variables, classification and regression decision trees (CART) were used. 82 species from 13 families of birds were identified: 21 residents (12 endemic to Peru) and 61 migratory species (22 from the North and Central Pacific, 3 from the Galapagos Islands and 36 from the Southern Pacific). Depending on the season, Humboldt penguin, Peruvian diving petrel, Guanay cormorant (endemic diving species), and Peruvian booby, gulls, terns (flying resident species), showed a negative association between numbers and distance from the coast. This association could be explained by restrictions on their flight capacity. For other groups like the tropical boobies and frigate birds, latitude was the most important 215
Eastern Boundary Upwelling Ecosystems Symposium variable that characterised their distribution. Storm-petrel distributions were related most strongly to water depth as they also use islands and headlands for breeding. Among migratory birds, Antarctic species were only present during the spring whereas other migrants were present all year, changing seasonally only by density. The distributions of albatrosses, large petrels, shearwaters, jaegers and skuas were determined mainly by extreme environmental changes (warming or cooling). In summary, these results suggest that the distribution of seabirds in the Peruvian upwelling system are the result of bird behaviour, oceanographic characteristics and the extreme environmental changes that might arise in the system. This research supports other studies on the at-sea distribution of seabirds in coastal upwelling systems and can be used to identify or define conservation areas, to evaluate the use of species and families as indicators of change in the environment, and to understand the interactions with anthropogenic activities.
4 June, 11:00 (P11 OP2)
Great white pelican predation on seabirds – an endemic behaviour to the Benguela Current ecosystem? M. De Ponte Machado Animal Demography Unit, University of Cape Town, Private Bag, Cape Town, 7701, South Africa. Email:
[email protected]
Opportunity could play an important role for the expression of an unusual predatory behavior by Great White Pelicans (Pelecanus onocrotalus, GWP). An otherwise fresh-water fish eating species, GWP of the West Coast of southern Africa are the only population of this species that consume large numbers of seabird chicks. The nutrient-rich Benguela waters and associated islands are the only place within their range of distribution that sustains large colonies of ground-nesting seabird species. From the early 90s pelican predation has been responsible for the breeding failure of extensive colonies of Cape and Crown Cormorants (P. capensis and P. coronatus), Kelp Gulls, Swift Terns and Cape Gannets (Morus capensis) in the islands of the West Coast of South Africa. GWP are unique amongst seven species of pelicans of the world at displaying this behaviour. Humboldt’s and California’s are the other eastern boundary upwelling ecosystems where pelicans occur. Californian Brown Pelicans (P. occidentalis californicus, CBP) have been observed eating seabird chicks and eggs. The scale and extent of CBP predation is considerably smaller, despite opportunity -large numbers of locally breeding seabirds- and need -they suffer starvation and breeding failures due to El Niño’s effect on pelagic fish. GWP population has increased drastically in the last decades in the Western Cape. It recovered from a minimum of 20-30 pairs in the mid 50s, after years of persecution and disrupted breeding. By the late 70s they had reached a steady population of about 250 pairs. From the mid 80s agricultural offal was available in large quantities to the pelicans, which fuelled a further 3-fold population increase, reaching a historical ceiling of 700 breeding pairs in 2003. Following an interruption in the availability of offal, pelican predation on seabirds intensified as they searched for alternative sources of food, reaching worrisome levels in 2005. Brown Pelicans on the other hand have also experienced large population fluctuations. They were classified as endangered following a sharp population decline in the 60s and 70s due to the widespread use of DDT. Following DDT’s ban most populations recovered. However, they experience varying food conditions caused by cyclical oceanographic phenomena, such as El Niño/Southern Oscillation (ENSO), which often cause reduced breeding and high juvenile mortality. In a few infrequent episodes they have been observed to predate on eggs and chicks of ardeids and Murres (Uria aalge) in Mexico and California. However, mass predation events, of the scale occurring in South Africa are not known to this species. No other incidents of predation are known from other areas of distribution of Brown Pelicans, including the Caribbean, Atlantic coast, and Humboldt systems. GWP and BP have different feeding and breeding habits. Although we cannot compare both species in terms of their ecological equivalence we can contrast their response to demographic fluctuations and predatory behaviour. A drastic reduction in the subsidised sources of food for an artificially increased GWP population could explain the difference in seabird predation scales. GWP predation events previous to large-scale human 216
Eastern Boundary Upwelling Ecosystems Symposium subsidisation are scarce and anecdotal, similar to records from BP. Human interference could once more have produced unforeseen cascading effects throughout the ecosystem. The visible benefit attained by subsidising a top predator such as the pelican can unleash complex conservation and management problems.
4 June, 11:15 (P11 OP3)
Fishers and marine birds competing for the same fish: foraging strategies and interactions S. Bertrand1,2, J.Carlos Marquez2 and H. Weimerskirch3 IRD, CRHMT, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France. Email:
[email protected] Instituto del Mar del Peru, Peru. 3 Centre d’Etudes Biologiques de Chizé, CNRS, France. 1 2
In Peru, the main fish resource, anchovy (Engraulis ringens), is foraged mostly by fishers, marine birds and marine mammals. The industrial fishery, about 1200 purse seiners, extracts from 5 to 10 million tons of anchovy each year. The fishery is managed among other ways by long fishing bans, covering up to 10 months a year recently. The main marine bird populations are the three guano producing species: the Peruvian booby (Sula variegata), the guanay cormorant (Phalacrocorax bougainvillii) and the Peruvian pelican (Pelecanus thagus). There is clearly a global competition for the resources at the top predator populations' levels, as shown by the global decline of bird populations since the fishery was developed in the fifties. However, it is still unclear how these two groups of top predators exactly behave and interact while foraging for the same anchovy concentrations. For instance at a regional spatial scale, two types of interactions may develop: (1) a positive one by mutual local enhancement between birds and fishers for detecting anchovy aggregations; (2) a negative one on birds from fishers owing to their dramatic extracting power (up to 150 000 tonnes.day-1) and their capacity to generate regional depletion of anchovy. To address these general questions, we propose here as a first step to analyse and compare the foraging strategies adopted by fishers and birds exploiting the same concentration of fish. In November 2007, we conducted a 12 day field experiment on a breeding colony of Peruvian boobies on a guano Island (Gañape Sur, -08º33 latitude, -78º57 longitude) off one of the main fishing port of the Peruvian coast, Chimbote. We fitted 59 birds with GPS loggers, most of them programmed for 1sfrequency fixes. Foraging trips during this breeding season last usually less than one day and birds have then to rely on relatively close fish aggregations. The fishery was opened for a 10-day period the second day of our experiment and the important fleet from Chimbote (about 300 units) deployed its effort in our study area. The entire industrial fishing fleet in Peru is fitted with Vessel Monitoring System (VMS), providing fixes for each vessel approximately every half hour. Fishing trips usually last from 20 to 30 hours. Here we contrast these two sources of data to compare fishers and birds foraging strategies while foraging on the same fish concentration: the characteristic scales of the foraging trips, the average number of fishing events by foraging trips, the searching effort (path sinuosity and scale-invariance). We then investigate for interaction between birds and fishers, studying the overlapping of their foraging areas and the evolution of the bird average heading in relation to the fishing fleet deployment.
4 June, 11:30 (P11 OP4)
Behavioural resilience of Benguela avian predators facing global change and their value as ecological indicators D. Grémillet1 and P. Ryan2 Centre National de la Recherche Scientifique, Centre d’Ecologie Fonctionnelle et Evolutive, 1919 Route de Mende, F-34 293 Montpellier Cedex 5, France. Email:
[email protected] 2 Percy Fitz Patrick Institute, DST/NRF Centre of Excellence, University of Cape Town, South Africa. 1
Most marine ecosystems are controlled by bottom-up dynamics. As a result, marine top-predators have been proposed to be useful indicators of ecological processes occurring at lower trophic levels. A prerequisite for this approach is a sound understanding of how top-predators react to environmental 217
Eastern Boundary Upwelling Ecosystems Symposium change that occur at a range of spatial and temporal scales. Seabirds are convenient indicators because they are easy to study at their breeding colonies, but strong philopatry to breeding colony can render them especially sensitive to spatial resource shifts. Population studies of seabirds from the Benguela upwelling zone revealed correlations between population size, breeding parameters, and some important components of the Benguela ecosystem e.g. pelagic fish stocks. A drawback of this method is that it only reveals trends a posteriori. As an alternative we propose to use the foraging efficiency of seabirds as a short-term indicator of the availability of pelagic fish in the southern Benguela. Recent improvements in biotelemetry techniques, in particular GPS tracking, enable the study of foraging movements and foraging efficiency of avian predators. Using results from recent tracking studies, and from the literature, we compare the foraging ecologies of the three main Benguela seabirds, Cape gannet Morus capensis, African penguin Spheniscus demersus, and Cape cormorant Phalacrocorax capensis, as well as the social structure of their populations. Using these data we demonstrate that these three species respond differently to environmental changes currently occurring in the Benguela, in particular to spatial shifts in food abundance. Cape gannets and African penguins demonstrate strong philopatry to breeding site, and thus are powerful ecological indicators of local change, whereas Cape cormorants exhibit greater behavioural plasticity and thus are less sensitive to local resource shifts. All three species provide useful insights into long-term, system-wide changes in food abundance.
4 June, 11:45 (P11 OP5)
Spatial and temporal variability in the cephalopod component of the diet of Cape fur seals along the Namibian coast P.J.N. de Bruyn1, M.N. Bester1, S. Kirkman2,3, S. Mecenero3 and J-P. Roux4 Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. Email:
[email protected] 2 Marine and Coastal Management, South Africa. 3 Avian Demography Unit, Department of Statistical Sciences, University of Cape Town, South Africa. 4 Ministry of Fisheries and Marine Resources, Namibia. 1
Scats of the Cape fur seal Arctocephalus pusillus pusillus were sampled at four mainland colonies, Cape Cross, Atlas Bay, Wolf Bay and Van Reenen Bay, along the Namibian coast over a period of eight years (1994-2001) to assess the diversity and, spatial - and temporal variation in the cephalopod component of the seal diet. Adequate temporal data was limited to Atlas and Wolf bay rookeries. Additional scat samples were collected from Possession Island seal colony (1999-2000) to gain a broader perspective of spatial variation. A uniform and low diversity of cephalopods, only six species amongst all colonies, was identified, indicating that independently the scat sampling method is unsatisfactory for determining species diversity within the diet. Given the ease of scat collection, this method does, however, provide valuable insight into the variability of the most important species in the diet. Ommastrephids dominated the cephalopod component of the diet of seals from Atlas/Wolf Bay and Cape Cross both in terms of wet weight and numbers. Sepia australis proved to be numerically the most important cephalopod in the diet of seals from Possession Island and Van Reenen Bay, while Octopus magnificus dominated at these colonies in terms of wet weight. Contrary to previous findings it is suggested that seals from Van Reenen Bay and Possession Island forage south of the upwelling cell at Lüderitz (in the southern Benguela ecosystem), while previous evidence of Atlas/Wolf Bay and Cape Cross seals foraging north of this upwelling cell (in the northern Benguela ecosystem) is supported. Clear seasonal patterns, both numerically and in wet weight terms, are identified for the Atlas/Wolf bay seals. The most important cephalopod prey species for seals from these rookeries, Todarodes angolensis illustrate proportional decline in weight contribution to the seals’ diet during winter, coinciding with a greater diversity of other cephalopod species in the diet at this time. Prey specimen size differences, within species between colonies, were identified, but lack of cephalopod life history and movement data, and scat sampling biases preclude adequate explanation of these findings, indicating the necessity for further studies. 218
Eastern Boundary Upwelling Ecosystems Symposium
4 June, 12:00 (P11 OP6)
Are the changes in the latitudinal distribution of fur seals influenced by the abundance, availability and distribution of Peruvian anchovy or by environment predictability? G. Yataco, J.C. Márquez and L. Alza Instituto del Mar del Peru, Esq Gamarra y Gral. Valle s/n. Chuchito, Callao, Peru. Email:
[email protected]
The South American fur seal is the only fur seal species that inhabits and breeds in the Peruvian coast. In Peru, the distribution of south American fur seals have been reported between Isla Mazorca and surrounding islets (11º21’S) and Punta Coles (17º41’S). Since an exploitation ban was established in 1976, population fluctuations were mainly determined by food availability and density-dependent factors of habitat. During the last 10 years, after a dramatic decrease due to “El Niño 97-98” event, the population is recovering slowly, at an average rate of 10% per year. Even though decrements were registered in 2001 (19%) and 2007 (12%), coinciding with the presence of La Niña event of moderate intensity, recovery has occurred. Until 1996, higher abundances of fur seals were concentrated in 15º-16ºS. After El Niño event 97-98, changes in latitudinal distribution were observed. In the first place, the distribution of this species has been restricted between Chincha Islands (13ºS) to Punta Coles (17ºS), hauling out and/or breeding at more than 12 sites. Since 2000 there has been no presence of individuals between 11ºS-13ºS. Secondly, the largest concentration of individuals is now between 17º-18ºS, which includes Punta Coles, the most important colony in abundance (51%) and pup production (61%) in the Peruvian coast. This greatly increases the degree of vulnerability of the species. In this study, we aim to explain how changes in the marine environment, abundance, distribution and availability of its principal prey, the Peruvian anchovy, affects the population structure and size of a specialist top predator like the South American fur seal along its distribution range. We analyse environmental changes from two approaches. First, we explore month and annual changes in distribution, abundance and prey availability. With the second approach we assess the magnitude and velocity of changes through rates and variances of variables as a measure of environment predictability. Population values were obtained from fur seal census data, using direct counts (total and age categories) of fur seals during the reproductive season (1996-2007), when it is most likely to find most individuals on land. Peruvian anchovy biomass, obtained from summer pelagic cruises between 11º-18ºS conducted by IMARPE from 1996 to 2007, is used as an abundance index and to define prey distribution. Prey availability is assessed from catch per unit effort (CPUE) data on latitudinal scale, obtained from IMARPE’s Logbook and On-board Observer Program, as well as anchovy landings of central (10º-15º59’59’’) and southern (15º59’59’’-southern limit) regions (1997-2007). Percentage of anchovy occurrence in fur seals diet will be used to contrast changes in the ecosystem and populations.
4 June, 12:15 (P11 OP7)
The impact of climate change on land-breeding predators in the Benguela ecosystem and its mitigation R. Crawford1, R. Altwegg2, T. Fairweather1, S. Kirkman1 and A. Makhado1 Department of Environmental Affairs and Tourism, Marine and Coastal Management, Private Bag X2, Rogge Bay, Cape Town, Western Cape, 8012, South Africa. Email:
[email protected] 2 Avian Demography Unit, University of Cape Town, South Africa. 1
Large changes in the numbers or distributions of several land-breeding predators in the Benguela ecosystem are well related to an altered abundance or distribution of their prey. Following the collapse of sardine Sardinops sagax in Namibia, numbers of African penguins Spheniscus demersus and Cape gannets Morus capensis there decreased by 90% and 95%, respectively. From the late 1960s, there was a sustained displacement south and east of Cape gannets and their epipelagic fish prey. Off South Africa, an eastward shift in the distribution of prey brought substantial mismatch in the distributions of the breeding localities and prey of seabirds, and led to severe decreases in seabird populations. In the Western Cape, penguins decreased by 45% between 2004 and 2006 and gannets by 40% between 2001/02 and 2005/06. The proportions of birds breeding, their reproductive success and their survival all decreased. The contribution of sardine to the diet of gannets fell from an average of 40% during 1987–2003 to 5–7% in 2005–2006. 219
Eastern Boundary Upwelling Ecosystems Symposium However, sardine has increased in the diet of gannets in the Eastern Cape, where the colony at Bird Island has grown rapidly. Off Namibia, there has been a northward shift in the distributions of Cape fur seals Arctocephalus pusillus and Cape cormorants Phalacrocorax capensis, which have established new breeding colonies in southern Angola. Although changes in the abundance of prey species are likely to be partly influenced by fishing, their altered distributions are most plausibly attributed to climate change. Evidence to support this contention includes recent large eastward expansions off South Africa in the breeding distributions of two seabirds that do not feed on commercially-exploited prey, southward movements of other seabirds and an increased frequency of disease outbreaks at seabird colonies. Farther south at South Africa’s Prince Edward Islands, there have also been large decreases in the populations of several seabirds that do not feed on commerciallyexploited prey. For rockhopper penguins Eudyptes chrysocome, which leave the islands for six months to over-winter, there has been a sustained decrease in their mass at arrival for breeding, suggesting poorer or more distant feeding at winter grounds. Climate-driven mismatch in the distributions of the breeding localities and prey of land-breeding marine predators requires novel interventions, if decreases of threatened predators are to be arrested. For species able to colonise new areas, e.g. seals and cormorants, the provision of suitable breeding habitat where prey is abundant, e.g. through fencing off headlands, may mitigate decreases. Species, such as penguins and gannets, which show strong site fidelity and natal philopatry, present a greater challenge. Their conservation is likely to require the spatial management of fisheries competing for prey, e.g. through precluding fishing around colonies. Limitation of mortality, e.g. controlling outbreaks of disease, will also be important.
4 June, 12:30 (P11 OP8)
Variation in the foraging behavior of marine mammals and seabirds in the north eastern Pacific Ocean D. Costa1, S. Shaffer1, M. Weise1, C. Kuhn2, P. Robinson1, S. Simmons1, M. Kappes1, J. Hassrick1 Y. Tremblay1 and W. Henry1 Presented by: L. Huckstadt1 Ecology & Evolutionary Biology, University of California, Center for Ocean Health, 100 Shaffer Rd, Santa Cruz, CA, 95060, USA. Email:
[email protected] 2 National Marine Mammal Laboratory, National Marine Fisheries Service, USA. 1
In an effort to understand climate driven variation in the foraging behavior and habitat use of top predators in the North Pacific Ocean, the Tagging of Pacific Pelagics (TOPP) program is using biologging technology to simultaneously map the location of marine vertebrates including sharks, tuna, albatrosses, seals and whales. This talk will focus on variations in the foraging behavior and habitat utilisation of Laysan and Black Footed Albatross, northern elephant seals, and California sea lions that have been examined using satellite tags attached to each species over a 4 year period from 2003-2007. The different life history patterns of these groups results in greater (sea lions) or lesser (albatross & elephant seals) susceptibility to environment variation. While Albatross and elephant seals have a life history pattern and breeding biology that allows them to forge over the North Pacific Transition Zone, California sea lions are restricted to the California Current. As a result we observed profound changes in the diet and foraging behavior of male and female California sea lions during the anomalously warm water events of 2005 and 2006. For sea lions these changes primarily included longer foraging trips that were farther from the breeding sites (females) or further offshore (males). In contrast albatross and elephant seals showed minimal changes in their foraging behavior, or changes that were harder to detect as the animals foraged over a wider region that was less affected by the 2005-2006 warm water event that was more restricted primarily to the California current.
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4 June, 12:45 (P11 OP9)
Comparing top predators abundances (seabirds and pinnipeds) in the Humboldt and Benguela systems E. Goya1 and R. Crawford2 Top Predator Research Unit, Instituto del Mar del Peru, Esq. Gamarra y Gral, Valle s/n, Chucuito, Callao, Peru. Email: egoya@ imarpe.gob.pe 2 Marine and Coastal Management, Department of Environmental Affairs and Tourism, South Africa. 1
By definition, top predators are downstream, in terms of energy flow, of changes within an ecosystem. This means that changes in ecosystem structure that also affect the energy flows through the system are likely to be reflected in changes at the top food chains. What are the most important factors affecting top predators population sizes in an ecosystem? Are the population sizes of top predators proportional to their productivity? What determines the final top predator abundance in a system? In order to address these questions, we compare top predators abundance (seabirds and pinnipeds) in the Humboldt and Benguela Systems, considering primary production, variability, trophic relationships, fisheries catches, fleet size and distribution, fisheries management and predators diet. Similar species groups are present within the Humboldt and Benguela systems, and they have been compared in terms of quantitative ecosystem indicators derived from inter-calibrated models, seabird assemblages and foraging aggregation and some life-history traits, among others. Both systems support large populations of seabirds and pinnipeds. Seabirds and seals have proved to be both valuable indicators of ecosystem functioning and susceptible to human impacts. There are 20 and 15 seabird species breeding in the Humboldt and Benguela upwelling systems, respectively. Several long-term trends of seabird populations in both systems have been similar, e.g. persistent decreases of Humboldt and African Penguins; Peruvian guano producing-seabirds and Cape Gannet and Cape Cormorant. These trends often reflect the impact of human activities, such as fishing. There are two pinnipeds in the Humboldt system, but just one in the Benguela. However, there are much lower numbers of seals in the Humboldt system despite a higher biomass of pelagic fish, the numbers differ dramatically in the order of magnitude, varying from thousands to millions. The higher inter-annual variability in the Humboldt system and a low availability of suitable breeding space are thought to contribute to the lower numbers in that system. Also, the large numbers of seals in the Benguela system feed substantially on mesopelagic fish in addition to epipelagics. Our results suggest that an in depth comparison of the long-term dynamics of the seabird and pinnipeds populations in relation to environmental perturbations and fishing will facilitate accounting for their needs in management of the respective fisheries. As Fowler (1999) mentioned, commercial fisheries should be regulated to mimic the allocation of consumption among the prey species by natural predators. Comparative studies will improve the understanding of the long-term dynamics of the two systems, and providing information to contribute with better criteria for a whole-system approach in the management of marine ecosystems.
4 June, 13:00 (P11 OP10)
Patterns of response of sharks to global change: an ecosystem based approach F. Arreguin-Sanchez, V.H. Cruz-Escalona, L. Salcido-Guevara, R. Ronzon-Rodriguez, M. Zetina-Rejón, I. Loeza and P. Del Monte-Luna Centro Interdisciplinario de Ciencias Marinas del IPN, Instituto Politécnico Nacional s/n, Col. Palo de Santa Rita, La Paz, Baja California Sur, 23090, Mexico. Email:
[email protected]
Sharks are characterised as vulnerable species because their life history, being stocks with a low turnover rate. Many shark species typically occupy high trophic levels and, under any ecosystem stress, it is expected they present symptoms of perturbation. However, we do not know if, under a similar impact, they respond following similar pattern, independently of the ecosystem they belong. Global change is a worldwide stress factor for ecosystems that follows a similar pattern. In this contribution we used trophic models for ecosystems representing different marine regions of the world to explore response of shark stocks to global change. Ecosim model is used to simulate global change effects on shark stocks. We represent global change patterns as the forcing factor impacting primary production, and response of sharks’ stocks 221
Eastern Boundary Upwelling Ecosystems Symposium were computed. Some ecosystem attributes were computed, such as changes in respiration, production, and turnover rates over trophic levels, and we discussed the ecosystem and stock processes behind shark responses, and particularly those explaining how signal of global change is propagated through the food web from the primary producers to higher trophic levels. Finn cycling and resilience are relevant process followed by flows to detritus, climate and biodiversity indices.
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P11 Posters Poster: P11 P1
Sympatric seals feeding behaviour adaptation to dramatic environmental changes in the Humboldt Current M. Arias Schreiber and J.C. Márquez Unidad de Depredaores Superiores, Instituto del Mar del Peru, Fahrenheitstrasse 6, Bremen, 28359, Germany. Email:
[email protected]
Feeding behaviour of sympatric South American fur seals (Arctocephalus australis) and sea lions (Otaria flavescens) at Punta Coles (18°S) in the Humboldt Current were determined from the analysis of faecal samples. Monthly faecal samples of both seals species were collected between April 1997 and December 2000, covering the period in which the occurrence of the strong El Niño 1997-98 was registered in the East Pacific Ocean. Sixtyone species of fish, one species of crustacean Pleuroncodes monodon, and at least one species of cephalopod were identified in the faecal samples. Fish was the most important prey, always exceeding the relative contribution of crustacean and cephalopods. The most important fish species according to percentages of occurrence for A. australis were the Peruvian anchovy Engraulis ringens (75%), the mote sculpin Normanichtys crockeri (18%), “barracuda” Sphyraena ensis (14%), the laternfish Lampanictus parvicauda (13%) and “agujilla” Scomberesox saurus (12%). For O. flavescens important fish species were N. crockeri (64%), E. ringens (60%), the Peruvian hake Merluccius gayi (11%), the “fraile” Aphos porosus (10%) and the silverside Odontesthes regia regia (8%). Both seals showed specialist feeding behaviour during normal conditions and higher fish diversity consumption during El Niño periods. A. australis was forced to introduce myctophids and bathipelagics as part of its diet during El Niño conditions, while O. flavescens introduced mostly demersal species like juveniles of Peruvian hakes. Multidimensional scaling plots of annual similarities between feeding behaviour of both seals showed that the amount of anchovy in the environment was playing an important role in the diet overlap of seals. Diet overlap was minimal in years with plenty of anchovy in the environment but also when anchovy biomass was extremely reduced due to El Niño. We discuss the adaptation of sympatric seals to dramatic environmental changes in the Humboldt Current based on our diet overlap results.
Poster: P11 P2
Rate predation on the nesting of Caretta caretta because of Ocypode cursor in Calheta de Pau beach, Boa Vista Island (Cape Verde rep.) A. Eiroa, M. Aguilera-Rodà, N. Varo, O. López and L.F. López-Jurado Department of Biology, University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain. Email:
[email protected]
Located in the Cape Verde Archipelago is one of the most important nesting population of Caretta caretta, Boa Vista Island being the principal nesting area. This population has been subject of research since 1998. During the 2004 nesting season, loggerhead nests in the beach of Calheta de Pau we monitored and an incubation period for the eggs of 57 days (n=193) was observed. The hatching success calculated was 47.2 % (n=30). The crab ghost (Ocypode cursor) is the principal predator of eggs and hatchlings on the beaches of Boa Vista. In this study, the rate of predation was also calculated at Calheta de Pau, and so the impact of this predator versus other factors that affect viability of the nest during the incubation (e.g. the tide).
Poster: P11 P3
The Columbus crab (Planes minutus) and loggerhead (Caretta caretta) relationship in the Canary Islands: parasitism or symbiosis? A. Liria Loza, P. Calabuig Miranda and L.F. López-Jurado Universidad de Las Palmas de Gran Canaria, c/ Lomo la Plana Nº 40, P3 - 1º A, Las Palmas de Gran Canaria, 35019, Spain. Email:
[email protected]
The Columbus crab (Planes minutus) is usually observed living on juvenile loggerhead turtles around the Canary Island. Both species are pelagic and can be commonly found along the Gulf Stream and the Canary Current. Only a few authors have studied the relationship between the two species, although there are many
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Eastern Boundary Upwelling Ecosystems Symposium comments and legends that are made by people not involved into the scientific research. This study aims to understand the relationship between the Columbus crab and loggerhead turtles on their way through the Canary Islands, trying to determine whether it is a relationship of symbiosis or parasitism.
Poster: P11 P4
Seabird breeding performance as an indicator of immediate ecosystem changes in a small scale J.C. Márquez1, M. Valverde1, C. Barriga1 and H. Weismerskirch2 1 2
Instituto del Mar del Peru, Esquina Gamarra y General Valle s/n Chuchito, Callao, Peru. Email:
[email protected] Centre d’Etudes Biologiques de Chizé, CNRS, France.
Seabirds may be useful indicators of change in marine ecosystems when aspects of their biology or behavior respond in a predictable manner to changes in food availability. The form of the relationship between a measurable behavioral or demographic parameter and local food supply largely determines the sensitivity and utility of that parameter as an indicator of marine ecosystem change. The Peruvian booby (Sula variegata) is a plunge diver, specialist feeder on anchovy (prefers adult sizes), presents low breeding synchronicity and biparental nest attendance. It lays 3 eggs on average and has the capability of laying eggs at the first sign of good feeding conditions as well as it could abandon the clutch if local food supply decreases. This Booby is currently the most abundant endemic seabird of the Humboldt Current system and feeds primarily on Peruvian anchovies (Engraulis ringens), the most abundant pelagic fish of the system. Its population has shown great fluctuations during the last two centuries, due to different factors that have affected its population dynamics. The most current important factors are on one hand oceanographic perturbations like El Niño and La Niña events, which may cause breeding failures and high mortality and on the other the industrial fishery targeting Peruvian anchovy. How the fishery affects breeding performance is still unknown. The aim of this study is to examine immediate effects of changes in local food supply produced by Anchovy fishery on Booby breeding performance and foraging behavior, as well as to determine their sensitivity and utility as an indicator of marine ecosystem change. Our study was carried out in November 2007 at Guañape Sur island (78º57’W, 8º33’S), a guano island localised 4.6 nautical miles off the Peruvian coast, supporting a large colony of Peruvian boobies (77 500 pairs). We investigated Booby breeding performance through nest attendance monitored hourly of 68 incubating and chick-rearing pairs during 9 days from 06:00 h to 18:00 h. Foraging behavior was assessed calculating the maximum daily foraging distance of 49 boobies obtained from GPS loggers during 12 days and measuring prey lengths regurgitated by 47 birds in 1 day. These behavioral aspects are contrasted with fishing effort and biological information (fish school depth and fish length) recorded by the IMARPE’s Logbook and On-board Observer Program from 141 anchovy Purse-Seiners sets within 70 nautical miles around the island during the same study period. We also compared Booby behavior with anchovy catches (5 144 vessels) and fish length distributions (617 vessels), which landed on three ports near the island (Chicama, Chimbote and Samanco). It is important to note that the fishery was opened for a 10-day period on the second day of our evaluation.
Poster: P11 P5
Overturning capacity in newly hatched common turtle (Caretta caretta) in captivity M. Medina Suárez, S. Jiménez Bordón, A. Liria Loza and L.F. López-Jurado Universidad de Las Palmas de Gran Canaria, c/ Severo Ochoa 16, 5º A, Las Palmas de Gran Canaria, 35015, Spain. Email:
[email protected]
The newly hatched loggerhead sea turtle (Caretta caretta) lose their capacity to overturn themselves with time after hatching. During the stage of “swimming frenzy” all individuals were able to overturn themselves, but this ability decreased with age. The bigger and stronger turtles did the overturn test with a major success, so the body weight at hatching was determinant to overturn, and probably increased the possibility of survival of the individuals. 224
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Poster: P11 P6
Seabirds response to a prey distributional change in South Africa P. Sabarros1, J. Durant1, R. Crawford2,3 and N.C. Stenseth1,4 Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway. Email:
[email protected] 2 Department of Environmental Affairs and Tourism, Marine and Coastal Management, South Africa. 3 Avian Demography Unit, Department of Statistical Sciences, University of Cape Town, South Africa. 4 Institute of Marine Research, Flødevigen Marine Research Station, Norway. 1
During the past two decades, the small pelagic fish previously strongly associated with the southern Benguela have progressively shifted eastward toward the Indian Ocean and have varied in abundance. This shift may reflect a habitat switch in response to global environmental change and/or may be a consequence of the intensive fishing in the western part. Sardine (Sardinops sagax) and anchovy (Engraulis encrasicolus) are known to be the key species in the wasp-waist food chain of the Benguela system and constitute the main food items for seabirds breeding along South African coast such as African penguin (Spheniscus demersus), Cape gannet (Morus capensis), Cape cormorant (Phalacrocorax capensis) and swift tern (Sterna bergii). The proportion of mature birds that decide to breed a given year and their breeding success depend on food availability (i.e. distribution and abundance of the prey). That context of prey distributional and abundance change gives the opportunity to investigate the effect of such perturbation on endemic and threatened seabirds breeding in South Africa.
Poster: P11 P7
Inter-annual occurrences of small cetaceans in purse-seine fishery operations in relation to environmental variables, 2001-2003 F. van Oordt and L. Alza Instituto del Mar del Peru, Esq. Gamarra y Gral Valle, Callao, Peru. Email:
[email protected]
The Humboldt Current System (HCS) is an important habitat for several predator species, among these 15 small cetaceans which are present in both inshore and offshore waters along the coast. Due to its high productivity, this system it subject to extensive fisheries mostly targeting Peruvian Anchovy, its key species, supporting an industrial purse seine fleet of about 1200 vessels. These results in events where small cetaceans occur during Peruvian Anchovy fishing operations; that are foraging on this prey, an important component of their diet, as has been described in previous works. The goal of the present study is to understand the circumstances in which small cetaceans are present during fishing operations in relation to environmental variables, fish school features and the fishing operation, identifying inter-annual differences. We analysed data from on board observations of fishing operations by the Logbook and Onboard Observer Program developed by IMARPE on the Anchovy Industrial Purse Seine Fishery, for 2001-2003. Each year was previously classified as cold, warm, and average, and were considered from April to November (irregular months were excluded). Occurrences are considered when any species of small cetaceans or dolphins are present during a fishing set, as they are associated to the school being fished. Average school depth, school size (referred to school height and total catch on the set), and prey length for occurrences are contrasted against those sets where small cetaceans were absent. Time of day, month, and geographic distribution, and SST were also analysed. Composition of small cetacean species occurring in fishing operations is also assessed for each period. Influence of fishing effort is assessed considering the effect of number of sets on the probability of occurrence. These relations are compared within each and between periods. In general, occurrences happen in larger schools and higher temperature range. Spatial distribution of fishing sets and occurrences seem to be more disperse during the cold period, and occurrences tend to happen in lower latitudes. Also, smaller prey was found in occurrences in the warm year. Small cetacean species composition shows no apparent difference within years. Preliminary results suggest that certain variables characterise the encounters of small cetaceans and fishing operations. Furthermore, apparent differences in prey length are observed between periods. Small cetacean species composition may de affecting these results. We consider that this information could be taken into account in the management of this fishery and the establishment of temporal or spatial bans to avoid interactions with this predator species, some of which present some level of vulnerability or endangered status. 225
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Poster: P11 P8
Climatic variability and the swordfish fishery in the eastern South Pacific Ocean: hypothesis and a conceptual model E. Yáñez, C. Silva and R. Vega Pontificia Universidad Católica de Valparaíso, venida Altamirano 1480, Valparaiso, 1020, Chile. Email:
[email protected]
The conceptual model of the system inhabited by the swordfish assumes that the fish’s life cycle includes the following different stages: a) larval, b) juvenile, and c) adult. The model also assumes that each phase of the life cycle is carried out in a different, geographically separated area: a) spawning zone (around Easter Island), b) rearing zone (mountains of Nazca), and c) feeding zone (Eastern South Pacific; 24ºS-40ºS). The general hypothesis of the model indicates that “environmental phenomena on diverse scales (interannual, seasonal, intraseasonal) that develops in the Pacific Ocean affect the basic biological processes of the swordfish in its different developmental stages and associated zones”. Moreover, a series of hypotheses were formulated for these temporal scales. Then, considering the climatologicaloceanographic information from the Pacific Ocean basin, and the biological and ecological data on swordfish reported and available in the international literature, along with the environmental and bio-fishery information from the Chilean swordfish fishery, an integrated conceptual model was proposed to address the link between the distribution and abundance of swordfish in the different stages of its life cycle, and the different spatio-temporal phenomena that affect the marine environment in the Pacific Ocean and the Eastern South Pacific. The model considers the variability in swordfish vulnerability and catchability (q), to be associated with fluctuations in the environmental conditions (environmental forcing). The integrated conceptual scheme implies, for example, that variations in the catch rates (fishery plane) are influenced by physical variability (physical environment plane) through the biological responses of the species and the pelagic community, which occur on similar spatial-temporal scales. Likewise, if the scale of these dynamics changes, the impact of the forcing could be reflected in human elements such as the economy, fishery administration, and employment.
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P12
Advances in ecosystem modelling of Eastern Boundary Upwelling Systems
4 June 10:15 (P12 KNS)
Modelling multi-trophic level marine ecosystems using the NEMURO family models: Scientific potential for eastern boundary current upwelling ecosystems S-I. Ito1, T. Okunishi1, F. Shido2, T. Hashioka3,4, M. Aita3, K. Rose5, M. Kishi3,6, B. Megrey7, Y. Yamanaka2,3,4 and F. Werner8 Tohoku National Fisheries Research Institute, FRA, 3-27-5, Shinhamacho, Shiogama, Miyagi 985-0001, Japan. Email:
[email protected] Graduate School of Environmental Science, Hokkaido University, Japan. 3 Frontier Research Center for Global Change, JAMSTEC, Japan. 4 Core Research for Evolutional Science and Technology, JSTA, Japan. 5 Department of Oceanography and Coastal Sciences, Louisiana State University, USA. 6 Faculty of Fisheries Sciences, Hokkaido University, Japan. 7 National Marine Fisheries Service, Alaska Fisheries Science Center, USA. 8 Department of Marine Sciences, University of North Carolina, USA. 1 2
NEMURO (North Pacific Ecosystem Model for Understanding Regional Oceanography) is a lower trophic level (LTL) ecosystem model applied to the North Pacific. NEMURO was extended to a multi-trophic level model NEMURO.FISH (NEMURO for Including Saury and Herring) by coupling a fish bioenergetics model to the LTL. Prey densities at specific points derived from NEMURO embedded in a global ocean general circulation model were used to predict saury and herring growth using NEMURO.FISH in a 50 year simulation. Results showed changes in fish growth coincided with the 1977-78, 1988-89, and 1998-99 regime shifts. However, growth responses were complex and included time lags in the modeled growth responses in comparison to observations. Also the fish growth response strongly depended on species and location. Of particular note were east-west differences within Pacific Basin. Three NEMURO.FISH models, which include more realistic fish migration, are in development. One was applied to Pacific saury and the feeding migration is assumed to be controlled by local optimal growth while the spawning migration optimizes the growth of hatched larvae. The model successfully reproduced both realistic seasonal migration and growth of Pacific saury. Another model was applied to Pacific sardine and the spawning migration mechanism was optimized by an artificial neural network (ANN) with local environmental factors. A genetic algorithm was used to adjust the ANN parameters to reproduce realistic migration of Japanese sardine. Although the above two models are single species models, the third one (NEMURO.SAN: NEMURO for Sardines and ANchovies) is a multi-species model which includes sardine, anchovy and a predator. The model is spatially-explicit, contains competition for food between fish species and also prey-predator interactions between fish species. NEMURO.SAN is now in development for the California Current ecosystem. In the future, we plan to apply NEMURO.SAN in hindcast scenarios to investigate mechanisms of species alternation, and to extend it to other major eastern and western boundary regions to compare the ecosystem structure between those sites. Finally, building on approaches where NEMURO has been applied to future predictions under IPCC scenarios, we consider the strategies for the implementation of NEMURO.SAN to make predictions of pelagic fish alternations under future climate scenarios.
4 June, 10:45 (P12 OP1)
Cross shelf structure of coastal upwelling: a two dimensional extension of Ekman's theory and a mechanism for inner shelf upwelling shut down P. Estrade1, P. Marchesiello2, A. Colin de Verdiere3 and C. Roy4 University of New South Wales, 3/136 Marine Parade, Maroubra, NSW, 2035, Australia. Email:
[email protected] IRD, Noumea, France. 3 Laboratoire de Physique des Oceans, Brest, France. 4 IRD/Laboratoire de Physique des Oceans, Brest, France. 1 2
Sea surface temperature images of the coastal upwelling regions off north west Africa show that the core of upwelling is sometimes located far from the coast. This has been documented in three regions that share 227
Eastern Boundary Upwelling Ecosystems Symposium a common feature, namely a wide and shallow continental shelf. This upwelling feature plays a key role in the ecology of the Canary Current system. It creates an innerfront which provides retention for biological material, e.g. fish eggs and larvae, in the highly productive nearshore environment. An analytical model has been developed based on a two dimensional extension of Ekman's solution. The linear and steady response of a homogeneous ocean forced by a constant alongshore wind provides a mechanism for the upwelling separation from the coast. The merging of the surface and bottom mixed layers induces a very weak cross shore circulation and a ``kinematic barrier'' for the Ekman transport divergence. The barrier is located near the isobath h=0.4D, where D is the thickness of Ekman layers. This yields an upwelling cell which is essentially concentrated in the region 0.5D
4 June, 11:00 (P12 OP2)
Ichthyop: a Lagrangian tool for modelling ichthyoplankton dynamics P. Verley1,2,4, C. Lett3, C. Mullon2, C. Parada5, T. Brochier2, P. Penven4 and B. Blanke1 Laboratoire de Physique des Océans. UMR 6523 CNRS/IFREMER/UBO, UFR Sciences et Techniques, 6 avenue Le Gorgeu, C.S.93837, 29238 Brest Cedex 3, France. Email:
[email protected] 2 IRD, UR ECOUP, CRHMT, Sète, France. 3 IRD, UR GEODES, Institut des Système Complexes, France. 4 IRD, UR ECOUP, Centre de Bretagne, France. 5 School of Aquatic and Fisheries Sciences, University of Washington, USA. 1
Ichthyop is a free Java tool designed to study the effects of physical and biological factors on ichthyoplankton dynamics. It simulates the main processes involved in fish early life: spawning, movement, growth, mortality and recruitment. The tool is an individual based model that uses as input time series of velocity, temperature and salinity fields archived from ROMS or MARS oceanic models. Ichthyop offers two functioning modes. The first one allows a visualisation of the transport of virtual eggs and larvae in a user-friendly graphic interface. The second mode enables to run series of simulations based on pre-defined sets of parameters, with a minimalist interface. Both modes generate output files that can be post-processed easily using graphic and statistical software. Ichthyop is a generic version of previous modelling experiments investigating the dynamics of anchovy and sardine ichthyoplankton in the Benguela, Humboldt and African Canary Current systems. References these works, information about Ichthyop and access to the download page are provided at http://www.eco-up.ird.fr/projects/ichthyop/.
4 June, 11:15 (P12 OP3)
Study of the wind variation effects in the upwelling system along the Peruvian Coast through data analysis and numerical modelling E. Aguirre University San Marcos Lima, Psje Ortigueras 196, Dpto 202, Villa Jardín, Lima/Lima 30, Peru. Email:
[email protected]
The objective of the present work was to study the effects of variability in the wind due to the El NiñoSouthern Oscillation events in the surface circulation patterns off the Peruvian coast, by means of data analysis and numerical modelling. It is focused the period of 1991-2000, when La Niña (1996-1997, 19982000) and El Niño events (1997-1998) were observed. These events had strong effects worldwide but very little is known about the local impacts on the circulation, thermocline structure and the Ekman dynamics off the Peruvian coast. The data analysed in the present study were collected on transects along 5°S and 15°S. The model used was an implementation of the Princeton Ocean Model (POM). The numerical simulations were forced with wind products relative to the period of interest (1991-2000). The simulations reproduced satisfactorily mean circulation patterns in the study area, confirming that in the nearshore region the wind is the main driving mechanism for coastal upwelling/downwelling. 228
Eastern Boundary Upwelling Ecosystems Symposium
4 June, 11:30 (P12 OP4)
Assessing spatial patterns in the size structure and sources of fish mortality for the fish communities in the southern Benguela ecosystem based on an IBM model: a comparison across three periods D. Ghebrehiwet1, Y. Shin2 and J.G. Field1 1 2
University of Cape Town, Cape Town, Western Cape, 7701, South Africa. Email:
[email protected] IRD/CRH, Sète, France.
Recent interest in ecosystem approach to fisheries necessitates the need to gauge and regulate impacts on the structure and function of ecosystems. To this end various indices of ecosystem status have been proposed; categorised into the following groups, size-based indicator, species-based indicator, trophodynamic indicators etc. Size-based indicators includes: mean size, mean maximum size, attributes of the size-spectra, and each of the indicators can be calculated at different levels of the ecological hierarchy (population, community, and ecosystem). A study, using EwE mass balance approach, compared the structure and function of the Benguela ecosystem between two periods (1980s and 1990s) while another study cross compared output of the EwE model to the output of the Individual Based Model OSMOSE and found reasonable agreement in the findings. Comparison of the ecosystem structure (in terms of size composition) across the three periods (1980s, 1990s, 2000s) has not been done previously. Furthermore there has been substantial change in the distribution pattern of some the modelled species in the later period. Thus patterns in the distribution of the slope of the size spectra are compared for three periods (1980s, 1990s, and 2000s) for the southern Benguela using the IBM OSMOSE output. Similarly the spatial distribution of the various sources of mortality (predation and fishing) was assessed. This modelling study is expected to provide insight into the structure of the ecosystem across the three periods. In addition, the combined result is expected to help characterise the three periods in terms of size composition and relative distribution of different sources of fish mortality.
4 June, 11:45 (P12 OP5)
Simulation of particle aggregation and export in an eastern boundary upwelling system G. Karakaş1, C. Schäfer-Neth1, G. Fischer2, P. Marchesiello3 and R. Schlitzer1 Alfred-Wegener-Institute, Am Alten Hafen 26, Bremerhaven, 27568, Germany. Email:
[email protected] University of Bremen, Germany. 3 IRD, Noumea, France. 1 2
Particle fluxes from the ocean's surface layers to its bottom are important means of carbon export and therefore have a crucial role in the global regulation of atmospheric CO2. A great extent of the particles sinking into deep layers do so in the form of aggregates or the so-called marine snow, which are produced by the coagulation of smaller particles. Eastern boundary upwelling systems retain elevated concentrations of aggregates due to high biological productivity and are distinguished by their enhanced export. We implemented an aggregation model into the biogeochemical model of ROMS (Regional Oceanic Modelling System) to simulate the distribution of particles in the water column and their downward transport in the NW African upwelling region. The model is based on a continuous size spectrum of aggregates, characterised by the prognostic aggregate mass and aggregate number concentration. Aggregates are produced as a result of particle collision due to turbulent shear and differential settling. The resultant biogeochemical model is comprised of 9 compartments: phytoplankton, aggregated phytoplankton, zooplankton, ammonium, nitrate, detritus, chlorophyll to carbon ratio, aggregate number concentration and aggregates. Phytoplankton, detritus and aggregates make up the aggregation pool. While phytoplankton, zooplankton, and detritus have specified sinking velocities, aggregates and aggregated phytoplanton have prognostic size dependent sinking. We present model sensitivity to aggregation parameters related to porosity and stickiness. We also compare the simulated carbon fluxes with those recorded by sediment trap deployments over the last several years as well as with those estimated by the original biogeochemical model. 229
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4 June, 12:00 (P12 OP6)
Modelling summer nutrient and phytoplankton dynamics on the west coast of Vancouver Island A. Peña and M. Foreman Department of Fisheries and Oceans, Institute of Ocean Sciences, 9860 West Saanich Road, PO Box 6000, Sidney, British Columbia, V8L 4B2, Canada. Email:
[email protected]
Large phytoplankton blooms are often found on the continental shelf off Vancouver Island associated with coastal upwelling. Results from a biological/circulation model (ROMS) developed to study factors influencing blooms dynamics will be presented. The biological model includes two size classes of phytoplankton and zooplankton, nitrate, ammonia and silicate. Model results showing the influence of upwelling and fresh water inputs on the growth of phytoplankton and the fate of the organic matter produced will be presented. We will discuss the importance of different sources of nutrients (i.e. wind-driven upwelling, topographically controlled upwelling, and the outflow from the Juan de Fuca Strait) on primary production and biogeochemical cycles. We seek to understand the effect of upwelling on the (i) plankton ecosystem structure and function, and (ii) the macronutrient fields of nitrate and silicate.
4 June, 12:15 (P12 OP7)
Comparing the contribution of vertical migration to onshore transport of anchovy larvae in different upwelling ecosystems: a modelling study C. Parada1, C. Mullon2, T. Brochier3, S. Soto4, L. Castro4 and C. van der Lingen5 School of Aquatic and Fisheries Sciences, University of Washington, 1122 Boat Street NE. Seattle, WA 98105, USA. Email: Carolina.
[email protected] 2 IRD, Paris, France. 3 IRD, UR ECO-UP, CRHMT, Sète, France. 4 Departamento de Oceanografía, Universidad de Concepción, Chile. 5 Marine and Coastal Management, South Africa. 1
Spatially-explicit individual-based models (IBMs) have been developed to examine the importance of diel vertical migration (DVM) of anchovy larvae as a mechanism for (1) enhancing transport from the spawning grounds to the nursery area and (2) transporting larvae to the inshore domain of the nursery area and hence counteracting offshore advection by favouring retention. This study uses these IBMs to examine and compare the importance of anchovy larvae DVM in three upwelling ecosystems, namely the southern Humboldt, northern Humboldt and southern Benguela ecosystems. The IBMs were coupled and forced by the same hydrodynamic model (Regional Ocean Model System; ROMS) using local climatological forcing, with 3D temperature and current fields being simulated with a horizontal resolution of approximately 9 km. The IBMs were configured using biological schemes and parameters that explained a high percentage of the variance in transport success in previous modelling attempts. Initial parameters and processes used include the effect of spawning date, spawning location, the influence of egg buoyancy and the impact of temperature on growth. An explicit diurnal vertical migration of larvae and post-larvae was incorporated to explore the effect of this behaviour on transport to the nursery area and/or retention within nursery area. Transport indices were extracted from each of the IBMs and larval trajectories modelled, and these were compared between ecosystems. Preliminary simulations for the southern Humboldt, without taking into account vertical migration, indicate that larval transport appears to be advective with a large amount of offshore transport. Some retention is observed in the Gulf of Arauco and the Itata River mouth, whereas transport was advective to the north and south of these regions. Some retention is associated with small eddies detached from upwelling filaments formed along the coast. The simulations including DVM are in progress. For the northern Humboldt, the potential nursery area extends very far offshore, but a shallow oxycline limits the vertical migration of larvae to the upper mixed layer. However, vertical migration within this superficial layer appears to be a major factor controlling the offshore advection of larvae in this system. Model results for the southern Benguela show a coarse-scale horizontal distribution pattern of larvae and post-larvae by age/size class that is similar to field observations, but the model does not represent distribution patterns observed for late larvae and pre-recruits. In the southern Benguela, observations show that early, small larvae are located offshore whereas older, larger post-larvae and pre-recruits are found closer to the continental shelf and the inner nursery grounds, possibly indicating that vertical migration is not an important mechanism for the onshore movement of anchovy larvae in this system. Hence this comparative modelling 230
Eastern Boundary Upwelling Ecosystems Symposium study has suggested that DVM by anchovy larvae appears to be important for transport and retention in the Northern Humboldt ecosystem, but not in the Southern Benguela ecosystems, while Southern Humboldt simulations are still in progress. Possible reasons for these results and biological modelling differences are discussed.
4 June, 12:30 (P12 OP8)
Perspectives of modelling cephalopod larval transport in the southern Africa and Canary Current upwelling systems R. Martins1,2, A. Faraj3, C. Lett4, N. Chang5, E. Machu6, M. Roberts1, C. Moloney2 and É. Vidal7 Marine and Coastal Management, Private Bag X2, Rogge Bay 8012, Cape Town, South Africa. Email:
[email protected] Dept. of Zoology, Faculty of Science, University of Cape Town, Private Bag, Rondeboch, 7701, Cape Town, South Africa. 3 Institut National de Recherche Halieutique, Morocco. 4 IRD, UR GEODES, Institut des Systèmes Complexes, Ecole Normale Supérieure de Lyon, France. 5 Dept. of Oceanography, Faculty of Science, University of Cape Town, South Africa. 6 IRD, UR ECO-UP, Institut National de Recherche Halieutique, Morocco. 7 Centro de Estudos do Mar, Universidade Federal do Paraná, Brazil. 1 2
Commercially-important cephalopod species of the African coast, like the chokka squid (Loligo reynaudii) off the southern coast and the common octopus (Octopus vulgaris) off the north-western coast, are associated to upwelling areas. Whereas the former is linked to a small-scale, seasonal coastal upwelling system, the latter is related to a large-scale upwelling system associated to the Canary Current. Loligo reynaudii is regarded as a conspicuous component of the food-web over the Agulhas Bank (South Africa), and average annual landings of up to 7000 tonnes sustain a small-scale but economically important directed fishery. On the other hand, although the role of Octopus vulgaris in the food-web system off Morrocco coast is still not well understood, their importance is clearly established by their abundance and high productivity, which sustain one of the most important octopus fisheries in the world. The recruitment of both species has been linked to inter-annual variability of the upwelling phenomenon. This clearly indicates that changes in the environment may impact the early-life stages (i.e., paralarvae) and, ultimately, the recruitment, of these species. Understanding the process leading the recruitment patterns represent one of the major ecological challenges for these species and has important implications on the fishery management. Despite paralarvae of both species hatching with a developed swimming capability, they are subject to some degree of passive transport by water movements. Passive, Lagrangian transport could be either favourable or detrimental to the recruitment, by retaining the paralarvae in suitable growth environments or carrying them to unfavourable areas. Thus, the role of the currents on the larval transport is paramount for a better understanding of the recruitment of these species. This goal has been pursued by using the Ichthyop Lagrangian tool for modelling ichthyoplankton dynamics. Modelling the transport of chokka squid and of common octopus paralarvae off the eastern South African and the western Moroccan coasts, respectively, is currently under investigation. Preliminary results and perspectives of using this comparative approach are presented and discussed.
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P12 Posters Poster: P12 P1
Modelling of the Moroccan Atlantic coast fisheries K. Elkalay1, K. Khalil2, M. Znari3 and M. Loudiki4 ELmar, Faculté Polydisciplinaire, B.P. 4162, Safi, Morocco. Email:
[email protected] EST, Morocco. 3 Biodiversité & Dynamique Ecosystèmes, Biologie, Faculté Sciences Semlalia, Morocco. 4 ELmar, Faculté Sciences Semlalia, Morocco. 1 2
The Ecopath model presented in this work documents the construction of the model of the Atlantic coast of Morocco. The Ecopath model can be used to; address ecological questions for example to evaluate ecosystem effects of fishing; predict movement and accumulation of contaminants and tracers (Ecotracer); and also model effects of environmental changes. The particular application for the model was to identify the effects of the major fisheries in each of the component systems, and the possible confounding effects of independently developed fisheries management plans. We note that, numerous upwelling cells, mainly between Safi (320 N) and Cape Blanc (200 N) are responsible for high primary production. The stocks of sardines (Sardina pilchardus) and octopus (Octopus vulgaris) are considered among the richest in the world. The model includes several functional groups of which some are fishes, grouped by size and commercial importance. It is by no means a finished model and there are a number of recommendations made that should result in a future model reflecting the ecosystem more accurately. A more informative approach would be to build an Ecopath model of the Moroccan coast which would include time series of catch and biomass estimates.
Poster: P12 P2
Ecosystem-based reference points for fisheries management in upwelling ecosystems S. Neira1,3, C. Moloney1, L. Shannon2, A. Jarre1, K. Watermeyer1 and P. Cury3 Marine Biology Research Centre, University of Cape Town, Rondebosh 7702, Cape Town, South Africa. Email:
[email protected] Marine and Coastal Management, South Africa. 3 Centre de Recherche Halieutique Méditerranéenne et Tropicale, IRD/IFREMER & Université Montpellier, France. 1 2
The global call for an ecosystem approach to fisheries (EAF) has led fishery science to consider not only the status of particular species, but also whole-ecosystem properties as motivation for management decisions. The definition of ecosystem indicators (EIs) and their reference points (ERPs) play a key role in this process. Previous work had proposed and evaluated a series of EIs in the most important upwelling ecosystems in the southern Hemisphere (i.e. the Benguela Current system and the Humboldt Current system). However, the definition of ERPs has not been fully evaluated with ecological thresholds remaining unknown or poorly understood, at least in the Humboldt system. In this paper, empirical data and model results concerning the southern Benguela and southern Humboldt subsystems are used in a comparative approach to propose ecosystem reference points for available EIs (i.e. Mean Trophic level of the catch and of the ecosystem, piscivores/planktivores and pelagic/demersal ratios of fish biomass and catch, and primary production required to sustain catch, among others). Considering that in most of the cases there is no agreement on specific target reference points, we explore two categories of ERPs: i) Baseline reference points (BRPs) describing the values of the corresponding EIs in a pristine or trophically-balanced fished food web, and ii) Ecological thresholds representing Limit reference points (LRPs), i.e. values of the indicators that, once crossed, move the system away from the desired state, sometimes in an irreversible way. BRPs are derived from previously constructed food web models of the Southern Humboldt (SH) and the Southern Benguela (SB) systems that represent the pristine and pre-industrial fishing periods. LRPs are determined by identifying breaking points in time series of available EIs using piecewise regression and other ecological constraints (i.e., PPR available for predators in the system). Later, EIs and their position with respect to their corresponding RPs are used to assess the ecosystem status of the southern Humboldt and southern Benguela ecosystems relative to pristine, ecologically-balanced fishing and undesired ecosystem states. BRPs and TRPs derived for the SH and SB are compared with theoretical and empirical information produced in other marine ecosystems around the world. We conclude the paper by proposing/discussing ecosystem-based control rules related to exceeding identified LRPs. 232
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Poster: P12 P3
A vew conceptual model of zooplankton respiration T. Packard1,2,3 and M. Gómez3 Instituto de Ciencias del Mar, Paseo Marítimo de la Barceloneta 37-49, 08003 Barcelona, Spain. Email:
[email protected] Bigelow Laboratory for Ocean Science, W. Boothbay Harbor, Maine 04575, USA. 3 Biological Oceanography Laboratory, Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira., 35017 Las Palmas de G.C., Canary Islands, Spain. 1 2
Oxygen consumption (R) is caused by the respiratory electron transfer system (ETS), not biomass. ETS is ubiquitous in zooplankton, determines the level of potential respiration (Φ), and is the enzyme system that ultimately oxidizes the products of food digestion, makes ATP, and consumes O2. Current respiration hypotheses are based on allometric relationships between R and biomass. The most accepted version at constant temperature (T) is R = i0M¾, where i0 is a constant. We argue that, for zooplankton, a Φ-based O2 consuming algorithm is more consistent with the cause of respiration. Our point: although biomass is related to respiration, the first-principles-cause of respiration is the ETS because it controls O2 consumption. Biomass, itself, is indirectly related to respiration because it packages the ETS. Consequently we propose bypassing the packaging and modelling respiration from ETS and hence Φ. This Φ is regulated by T according to Arrhenius theory and by specific reactants (S) that sustain the redox reactions of O2 consumption according to Michaelis-Menten kinetics. Our model not only describes respiration over a large range of body sizes but also explains and accurately predicts respiration on the short time scales. At constant temperature our model takes the form: R = Φ S/(Km +S) where Ea is the Arrhenius activation energy; Rg, the gas constant; Km, the Michaelis-Menten constant.
Poster: P12 P4
Forecasting anchovy catches (Engraulis ringens) in northern Chile: non-linear multivariate approach E. Yáñez1, F. Plaza1, J. Carlos Gutiérrez2, I. Pulido2 and N. Rodríguez1 1 2
Pontificia Universidad Católica de Valparaíso, Casilla 1020, Valparaíso, Chile. Email:
[email protected] Universidad de Huelva, Spain.
The performance of artificial neural networks (ANN’s) monthly anchovy (Engraulis ringens) catches forecast models in northern Chile (18º21’S-24ºS), considering ten environmental variables, the fishing effort and the anchovy catches between 1963 and 2005, was analysed. A previous analysis of the data was carried out using principal components analysis and a non-linear cross correlation technique. The model used is a multi layer perceptron architecture trained with the Levenberg-Marquardt algorithm. The results involved ANN’s models having as inputs the sea surface temperature (SST) in Antofagasta, the SST in the Niño3+4 region, the anchovy catches, and the fishing effort. The Antofagasta SST lag (-6, -7, -8 months) could be related to anchovy recruitment; while the SST in the Niño3+4 region lag (-3, -4, -5 months) could be related to coastal trapped waves affecting the anchovy availability. The external validation process shows an explained variance higher than 70%, the standard error of prediction was lower than 25%. The strong correlation among the estimated and observed anchovy catches in the external validation phases suggest that calibrated models captured the general trend of the historical data and therefore these models could be used to carry out an accuracy forecast.
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List of participants Abrantes, Fatima INETInovação Estrada da Portela, Zambujal, Aptdo 7586 Amadora 2721-866 Amadora Portugal
[email protected]
Albert, Aurélie Laboratoire Laboratoire d'Océanographie et du Climat Bureau 427, 4 Place Jussieu, Boite 100 Paris 75005 France
[email protected]
Aguero, Max ICSED Casilla 27016 Las Condes Santiago 6782236 Chile
[email protected]
Alferi Poggio, Natalia Avenida Trinidad 55 - 4º piso - puerta 422 San Cristobal de La Laguna 38204 Spain
[email protected] Alheit, Juergen Leibniz Institute for Baltic Sea Research Seestr. 15 Warnemuende 18119 Germany
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Aguiar González, Miguel Borja Universidad de Las Palmas de Gran Canaria Facultad Ciencias del Mar Campus Universitario de Tafira Las Palmas de Gran Canaria 35017 Spain
[email protected]
Alonso González, Iván Julio Universidad de Las Palmas de Gran Canaria Casillas del Angel nº 42A Puerto del Rosario 35611 Spain
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Aguilera Rodà, Mireia Universidad de Las Palmas de Gran Canaria c/Honduras 84 Agüimes 35260 Spain
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Alvarez, Leonardo Universidad Autónoma de Baja California Sur Km 5.5 Carretera al Sur Colonia El Mezquitito La Paz 23080 Mexico
[email protected]
Aguirre, Enrique University San Marcos Lima Psje Ortigueras 196, Dpto 202, Villa Jardín Lima 30 Peru
[email protected] Agujetas, Julio Heriot-Watt University / STRI 5/8 Waverley Park Edinburgh EH8 8EW United Kingdom
[email protected]
Álvarez Salgado, Xose Anton Instituto de Investigaciones Marinas Eduardo Cabello 6 Vigo 36208 Spain
[email protected]
Aksissou, Mustapha University Abdelmalek Essaadi Faculty of Science, Department of Biology PO Box 2121 Tetouan 93002 Morocco
[email protected]
Alves, Jose IGIDL / FCUL Rua Virgilio Correia n 2 6 ESQ Lisboa 1600-223 Portugal
[email protected]
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Eastern Boundary Upwelling Ecosystems Symposium Alza, Luis Instituto del Mar del Peru Esq. Gamarra y Gral Valle s/n Callao Peru
[email protected]
Aristizabal, Manuela Universidad de Las Palmas de Gran Canaria Parque Central torre 6 piso 7c Las Palmas de Gran Canaria 35013 Spain
[email protected]
Anabalon Molina, Valeria Soledad COPAS Casilla 44 Dichato VIII Chile
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Arreguin-Sanchez, Francisco Centro Interdisciplinario de Ciencias Marinas del IPN Instituto Politécnico Nacional s/n Col. Palo de Santa Rita La Paz 23090 Mexico
[email protected]
Andrade Martinez, María Paz Universidad de Las Palmas de Gran Canaria Av. Mesa y Lopez 88 Las Palmas de Gran Canaria 35010 Spain
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Arteaga, Lionel Universidad Simon Bolivar av Principal El Hatillo. Calle Autocine. Edif Pina apt-8B. La Boyera, El Hatiilo, Edo. Mirandas Caracas 1083 Venezuela
[email protected]
Anfuso, Eleonora University of Cadiz Cayetano del toro 54, 10 N Cadiz 11011 Spain
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Atmani, Hmida Institut National des Ressources Halieutiques 2 Rue Tiznit Casablanca 20000 Morocco
[email protected]
Angélico, Maria Manuel INRB/IPIMAR - Fisheries Research Institute Av. Brasilia Lisbon 1449-006 Portugal
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Auel, Holger University of Bremen P.O. Box 330 440 Bremen D-28334 Germany
[email protected]
Antezana, Tarsicio Universidad de Concepción P.O. Box 4010 Concepción 4089100 Chile
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Baisnée, Pierre-François Institut de Recherche pour le Développement CRH/IRD - Av. Jean Monnet - BP 171 Sète cedex 34203 France
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Arias Schreiber, Milena Instituto del Mar del Peru Fahrenheitstrasse 6 Bremen 28359 Germany
[email protected]
Bakun, Andy Rosenstiel School of Marine and Atmospheric Science University of Miami 4600 Rickenbacker Causeway Miami FL 33149 USA
[email protected]
Arístegui, Javier Universidad de Las Palmas de Gran Canaria Campus de Tafira, Facultad de Ciencias del Mar Las Palmas de Gran Canaria 35300 Spain
[email protected]
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Eastern Boundary Upwelling Ecosystems Symposium Balguerías, Eduardo Instituto Español de Oceanografía Avenida de Brasil, 31 Madrid 28080 Spain
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Barrera, Anna Universidad de Las Palmas de Gran Canaria c/Mare de Deu de Montserrat, 14, bjs L'Hospitalet de Llobregat (Barcelona) 8901 Spain
[email protected]
Ballon Soto, Roberto Michael UR-097, ECO-UP/IRD Teruel 375 Miraflores Lima-18 Peru
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Barth, Jack Oregon State University 104 COAS Admin Bldg Corvallis 97331-5503 United States of America
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Baltar, Federico Universidad de Las Palmas de Gran Canaria Campus Universitario de Tafira Edif. Ciencias Básicas. Ciencias del Mar Las Palmas de Gran Canaria 35017 Spain
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Barton, Eric Instituto de Investigaciones Marinas (CSIC) IIM Eduardo Cabello 6 Vigo 36208 Spain
[email protected] Batteen, Mary Naval Postgraduate School Dept of Oceanography, Code OC/Bv Naval Postgraduate School, 833 Dyer Road Monterey 93943 United States of America
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Bange, Hermann IFM-GEOMAR Duesternbrooker Weg 20 Kiel 24105 Germany
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Bauleth D'Almeida, Graça Ministry of Fisheries and Marine Resources Strand Street Po Box 912 Swakopmund 9000 Namibia
[email protected]
Banks, Stuart Charles Darwin Foundation for the Galapagos Islands Charles Darwin Research Station Puerto Ayora 17/01/3891 Ecuador
[email protected] Barange, Manuel Plymouth Marine Laboratory Prospect Place Plymouth PL1 3DH United Kingdom
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Bel Madani, Ali Institut de Recherche pour le Développement IRD/IMARPE/CIMOBP Esquina Gamarra y General Valle s/n Chucuito Callao Peru
[email protected]
Barlow, Ray Marine & Coastal Management Private Bag X2 Roggebaai Cape Town 8012 South Africa
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Ben Alaya, Hajer University of Tunisia Campus El Manar tunis Tunis 2062 Tunisia
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Eastern Boundary Upwelling Ecosystems Symposium Benazzouz, Aïssa Institut National de Recherche Halieutique 2 Rue Tiznit Casablanca 20100 Morocco
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Blanchette, Carol University of California Marine Science Institute Santa Barbara 93106 United States of America
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Benítez Barrios, Verónica María Universidad de Las Palmas de Gran Canaria Tafira Baja. Campus Universitario. CCM Las Palmas de Gran Canaria 35017 Spain
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Blanke, Bruno Laboratoire de Physique des Océans UFR Sciences et Techniques 6 avenue Le Gorgeu, CS 93837 Brest 29238 France
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Bertrand, Arnaud Institut de Recherche pour le Développement Teruel 357 Casilla Postal 18-1209 Miraflores Lima 18 Peru
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Blasco, Dolors Institut Ciències del Mar, CSIC Passeig Marítim de la Barceloneta 37-49 Barcelona 08003 Spain
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Bertrand, Sophie Institut de Recherche pour le Développement IRD Représentation du Pérou Teruel 357 - Casilla 18-1209 - Miraflores Lima 18 Peru
[email protected]
Bode, Antonio Instituto Español de Oceanografia Apdo. 130 A Coruña 15080 Spain
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Bester, Marthán University of Pretoria Department of Zoology & Entomology Pretoria South Africa
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Bograd, Steven NOAA-NMFS 1352 Lighthouse Avenue Pacific Grove 93950 United States of America
[email protected]
Bianchi, Gabriella FAO Viale delle Terme di Caracalla Roma 100 Italy
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Borges, Maria de Fatima Instituto de Investigação das Pescas e do Mar Avenida de Brasília Lisboa 1449-006 Portugal
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Biccard, Aiden University of Cape Town 11 Ashbury Road Plumstead Cape Town 7800 South Africa
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Boucharel, Julien Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS) 14 Avenue Edouard Belin Toulouse 31400 France
[email protected]
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Eastern Boundary Upwelling Ecosystems Symposium Bouhadad, Rachid USTHB BP, 32, El Alia- Bab ezzouar, 16111 Algiers 213 Algeria
[email protected]
Buchholz, Friedrich Alfred Wegener Institute Ostkaje 1118 Helgoland 27498 Germany
[email protected]
Bouloubassi, Ioanna CNRS & University P. et M. Curie Case 100, 4 Place Jussieu Paris 75252 France
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Cabal Naves, Jesus Instituto Español de Oceanografía Avda. Príncipe de Asturias 70 bis Gijón 33212 Spain
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Branch, George University of Cape Town Zoology Department Rondebosch 7701 South Africa
[email protected]
Caballero-Alfonso, Ángela Las Palmas de Gran Canaria University Campus Universitario de Tafira, s/n Edif. CC Básicas, Ciencias del Mar (B-203) Las Palmas de Gran Canaria 35017 Spain
[email protected]
Bravo, Luis Universidad de Concepción Cabina 5, Barrio Universitario Concepción 4070043 Chile
[email protected]
Cahuin Villanueva, Sandra Marisol Universidad de Concepción Barrio Universitario s/n Concepción 8340422 Chile
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Brochier, Timothée
Caldentey, Paula Universidad de Las Palmas de Gran Canaria Campus de Tafira,Facultad Ciencias del Mar, B201 Las Palmas de Gran Canaria 35017 Spain
[email protected]
IRD (EUR-OCEANS)
Calle hierro, 3 tercer piso Las Palmas de Gran Canaria 35008 Spain
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Camacho-Ibar, Victor Universidad Autónoma de Baja California PO Box 453 Ensenada 22830 Mexico
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Broitman, Bernardo National Center for Ecological Analysis & Synthesis 735 State St. suite 300 Santa Barbara 93117 United States of America
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Capet, Xavier University of Sao Paulo Programa de Engenharia oceanica - UFRJ Centro de Tecnologia - Bloco C - Sala 203 Ilha do Fundao 21949-900 Brazil
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Brunet, Christophe Stazione Zoologica A. Dohrn Villa Comunale Naples 80121 Italy
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Eastern Boundary Upwelling Ecosystems Symposium Castillo, Ruth Instituto del Mar del Peru Jr. Pedro Torres Malarin 141 Pueblo Libre Lima 21 Peru
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Charpentier, Jose Universidad de Concepción Cabina 7, barrio Universitario Concepción 4070386 Chile
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Castillo-Jordan, Claudio Universidad de Concepción Barrio Universitario s/n Cabina 9 Concepción Chile
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Chavez, Francisco Monterey Bay Aquarium Research Institute 7700 Sandholdt Road Moss Landing 95039 United States of America
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Castrillejo, Maxi Universidad de Las Palmas de Gran Canaria Jose Mesa y Lopez 59-13c Las Palmas de Gran Canaria 35010 Spain
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Checkley, David, Jr. Scripps Institution of Oceanography La Jolla, CA 92093-0218 USA
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Castro, José Juan Universidad de Las Palmas de Gran Canaria Campus de Tafira, Edf. Ciencias Básicas (B-203.1) Las Palmas de Gran Canaria 35017 Spain
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Chen, Jixin State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China (Peoples Republic of)
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Castro, Carmen Instituto de Investigaciones Marinas Eduardo Cabello 6 Vigo 36208 Spain
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Chernyshkov, Pavel AtlantNIRO 5, Dmitry Donskoy str. Kaliningrad 236000 Russia
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Cazassus, Fabienne University of Cape Town Marine and Coastal Management Private Bag X2 Rogge Bay 8012 South Africa
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Chlaida, Malika Institut National des Ressources Halieutiques 2 Rue Tiznit, Casablanca 01 20000 Morocco
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Chaigneau, Alexis IRD/IMARPE Esquina general Gamarra y Valle Callao Peru
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Cobas-Garcia, Marcos Instituto Español de Oceanografía Paseo Maritimo Alcalde Francisco Vazquez, 10 A Coruña 15001 Spain
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Chang, Nicolette University of Cape Town Department of Oceanography Rondebosch Cape Town 7701 South Africa
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Codispoti, Louis University of Maryland Centre for Environ. Science P.O. Box 775 Cambridge 21613-0775 United States of America
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Eastern Boundary Upwelling Ecosystems Symposium Colas, Francois University of California, Los Angeles IGPP , UCLA 405 Charles E. Young Dr. Los Angeles 90405 United States of America
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Cruz, Joana INRB-IPIMAR Av. Brasília s/n, 1449-006 Lisboa Lisbon 1449-006 Portugal
[email protected] Cubillos, Andrés Universidad de Concepción Barrio Universitario s/n Concepción Chile
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Comas-Rodríguez, Isis Universidad de Las Palmas de Gran Canaria Campus Universitario de Tafira Departamento de Física (Lab. F-214) Las Palmas de Gran Canaria 35017 Spain
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Cubillos, Luis Universidad de Concepción Barrio Universitario s/n, Casilla 160-C Concepción Chile
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Cornejo-D'Ottone, Marcela Universidad de Concepción Cabina7 Barrio Universitario s/n Casilla 160C Concepción 4070553 Chile
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Currie, Bronwen Ministry of Fisheries and Marine Resources P.O. Box 912, Strand Street Swakopmund 9000 Namibia
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Costa, Daniel University of California Center for Ocean Health 100 Shaffer Rd Santa Cruz 95060 United States of America
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Currie, Jock University of Cape Town 12 Mowen street Swakopmund Namibia
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Crawford, Robert Marine and Coastal Management Private Bag X2 Rogge Bay Cape Town 8012 South Africa
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Cury, Philippe Institut de Recherche pour le Développement Avenue Jean Monnet BP 171 Sète cedex 34203 France
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Criales Hernandez, Maria Isabel Instituto del Mar del Peru Esquina Gamarra y General Valle s/n Chicuito Callao Lima Callao 1 Peru
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Da Silva, Antonio National Institute of Fishery Research Rua Mortala Mohamed Luanda 2601 Angola
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Crosnier, Laurence Mercator-Ocean 8-10 rue Hermes Parc Technologique du Canal Ramonville St Agne 31520 France
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Dadou, Isabelle LEGOS OMP 14 Avenue Edouard BELIN Toulouse 31400 France
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Eastern Boundary Upwelling Ecosystems Symposium Dagorne, Dominique Institut de Recherche pour le Développement IRD Bretagne BP70 Plouzane France
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Dewitte, Boris Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS) 14 Avenue Edouard Belin Toulouse 31400 France
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Davies, Helen Sustainable Fishing Solutions Lt. 2 Oak Court Pennington Close Pennington SO41 8JF United Kingdom
[email protected]
Dias, Joaquim Fund. FCUL - Instituto de Oceanografia Instituto de Oceanografia, Campo Grande Lisboa 1749-016 Portugal
[email protected] Di Lorenzo, Emanuele Georgia Institute of Technology Atlanta, GA 30332 United States of America
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D'Croz, Luis Smithsonian Tropical Research Institute Balboa, Ancon Apartado 0843-03092 Panama
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Dominguez Obregón, Noel Instituto del Mar del Peru Esq. Gamarra y Gral Valle s/n Chucuito - Callao Callao 511 Peru
[email protected]
de Bruyn, Nico University of Pretoria Department of Zoology & Entomology Pretoria South Africa
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Donoso, David University of Concepción Cabina 5, Barrio Universitario s/n Concepción 4070386 Chile
[email protected]
de Ponte Machado, Marta University of Cape Town ADU. University of Cape Town. Private Bag Cape Town 7701 South Africa
[email protected] Demarcq, Hervé Institut de Recherche pour le Développement Avenue Jean Monet Sète 34203 France
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Dopolo, Mbulelo Marine and Coastal Management Private Bag X2 Rogge Bay Cape Town 8012 South Africa
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Devis-Morales, Andrea Universidad de Concepción Casiila 160-C, Cabina 5 Concepción 4070386 Chile
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Doval, Marylo INTECMAR Peirao de Vilaxoan,s/n,36611 Villagarcia, Pontevedra 36611 Spain
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Devol, Allan University of Washington Box 355351 Seattle 98195 United States of America
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Dove, Veronica Eduardo Mondlane University Julius Nherere Ave., Main Campus Maputo P.O. Box 257 Mozambique
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Eastern Boundary Upwelling Ecosystems Symposium du Penhoat, Yves IRD/LEGOS LEGOS/OMP, 14 avenue Edouard Belin Toulouse 31400 France
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Eiroa, Airam Universidad de Las Palmas de Gran Canaria Canalejas 84, 3ºizq Las Palmas de Gran Canaria 35003 Spain
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Dubert, Jesus Univ- Aveiro, Portugal Campus de Santiago, Departamento de Física, Universidade de Aveiro Aveiro 3810-193 Portugal
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Ekau, Werner Center for Tropical Marine Ecology Fahrenheitstr. 6 Bremen 28359 Germany
[email protected] El hafa, Mohamed Université Ibn Zohr Faculté des Sciences Agadir Departement de Biologie Faculté des Sciences B.P. 8106 Cité Dakhla Agadir Agadir 80000 Morocco
[email protected]
Durazo, Reginaldo Universidad Autónoma de Baja California KM 103 Carret Tijuana Ensenada 22860 Mexico
[email protected] Duteil, Olaf Laboratoire d'Océanographie et du Climat Tour 45-55, 4eme etage 4 place Jussieu Paris 75005 France
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El Ouizgani, Hassan Faculté des Sciences Agadir BP 8106 Agadir 80000 Morocco
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Ebaye, Mohamed Mahmoud PNBA Av. Gamal Abdel Nasser BP: 5355 Nouakchott 1234 Mauritania
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Eldin, Gérard Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (CNRS/CNES/IRD/UPS) 14 Avenue Edouard Belin Toulouse 31400 France
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Echevarría, Fidel University of Cádiz Campus Rio San Pedro Puerto Real 11510 Spain
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Eleuterio, Yáñez Pontificia Universidad Católica de Valparaíso Av. Altamirano 1480, Valparaíso, Chile Valparaíso 1020 Chile
[email protected]
Echevin, Vincent IRD/LOCEAN/IPSL LOCEAN, UPMC, Boite 100 4 place Jussieu Paris 75252 France
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Elkalay, Khalid Faculté Polydisciplinaire B.P. 4162 Safi 46000 Morocco
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Eastern Boundary Upwelling Ecosystems Symposium Enriquez, Edgardo Instituto del Mar del Peru Esq. Gamarra y Gral Valle s/n Chucuito Callao 1 Peru
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Farah hounaida, Idrissi Institut National de Recherche Halieutique 2 Rue Tiznit Casablanca Morocco 20000
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Escribano, Ruben Universidad de Concepción Estacion de Biologia Marina,-Dichato Dichato 160-C Chile
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Farber-Lorda, Jaime Centro de Investigación Científica y de Educación Carr. Tijuana-Ensenada, Km. 107. Ensenada 22830 Mexico
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Escudero, Yasmin Instituto del Mar del Peru Jr. Simón Bolívar 139 Dpto. 404 San Miguel Lima 32 Peru
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Farias, Laura University of Concepción Cabina 7 s/n. Barrio Universitario Concepción 160-c Chile
[email protected]
Espinoza, Pepe Instituto del Mar del Peru Esquina Gamarra y Gral. valle s/n Callao 1 Peru
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Fernández, Lourdes Instituto Español de Oceanografia Puerto Pesquero s/n Fuengirola 29640 Spain
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Espinoza, Oscar Instituto de Investigaciones Marinas Eduardo Cabello 6 Vigo 3608 Spain
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Fernández, Camila Universidad de Concepción PROFC Cabina 7 Barrio Universitario s/n Casilla 160-C Concepción Chile
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Estrada Allis, Sheila Natalí Universidad de Las Palmas de Gran Canaria Av. Escaleritas, Nº 66, 5º D Las Palmas de Gran Canaria 35011 Spain
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Fewings, Melanie University of California at Santa Barbara 6715 Ellison Hall Santa Barbara 93106-3060 United States of America
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Estrade, Philippe University of New South Wales 3/136 Marine Parade Maroubra 2035 Australia
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Fiedler, Bjoern IFM-GEOMAR Kiel Duesternbrooker Weg 20 Kiel 24105 Germany
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Ettahiri, Omar Institut National des Ressources Halieutiques 2 Rue Tiznit Casablanca Morocco 20000
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243
Eastern Boundary Upwelling Ecosystems Symposium Figueiras, Francisco G. Instituto de Investigaciones Marinas-Instituto de Investigaciones Marinas (CSIC) Eduardo Cabello 6 Vigo 36208 Spain
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Gallegos Alejos, Percy Laboratorio de Ecologia Marina. Fac. de Ciencias Biológicas Universidad Nacional Mayor de San Marcos Lima 11 Peru
[email protected] Garcia Weil, Luis Departamento de Física, Universidad de Las Palmas de Gran Canaria Campus de Tafira s/n - Ed. de Ciencias Básicas Las Palmas de Gran Canaria 35017 Spain
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Fischer, Gerhard Geosciences Department University of Bremen Klagenfurter Strasse, Bremen 28359 Germany
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Garçon, Véronique Camille Centre National de la Recherche Scientifique 18 Avenue Edouard Belin Toulouse CEDEX 9 31401 France
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Flores-Fernandez, Carola Dpt. of Anthropology University of California, Santa Barbara Santa Barbara 93106 United States of America
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Garreaud, René Universidad de Chile Blanco Encalada 2002 Santiago 2777 Chile
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Franchy Gil, Gara Las Palmas de Gran Canaria University C/Arminda, 11 Las Palmas de Gran Canaria 35015 Spain
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Garrido, Susana Univ. Lisbon/IPIMAR/ICM-CSIC Av. Brasilia s/n Lisbon 1449-006 Portugal
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Franklin, Daniel University of East Anglia Sch. Environmental Sciences Norwich NR4 7TJ United Kingdom
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Gasol, Josep Institut de Ciències del Mar-CMIMA, CSIC Pg Marítim de la Barceloneta 37-49 Barcelona 8003 Spain
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Fréon, Pierre Institut de Recherche pour le Développement Rue Jean Monnet Sète 34203 France
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Gerlotto, Francois CRH/Institut de Recherche pour le Développement BP 171 - avenue Jean Monnet 34203 Sète cedex France
[email protected] Ghebrehiwet, Dawit University of Cape Town Marine Biology Research Centre Cape Town 7701 South Africa
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Gallegos, Mauricio Universidad de Concepción Cabina7 Barrio Universitario s/n Casilla 160C Concepción 4070553 Chile
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244
Eastern Boundary Upwelling Ecosystems Symposium Giglio, Susana Universidad de Concepción Barrio Universitario s/n, Cabina7 T4146 Chile
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Gomez-Valdes, Jose Centro de Investigación Científica y de Educación Superior de Ensenada Km 107 Carretera Tijuana-Ensenada Ensenada 22860 Mexico
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Glessmer, Mirjam IFM-GEOMAR Düsternbrooker Weg 20 Kiel 24105 Germany
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Gómez-Valdivia, Felipe Centro de Investigación Científica y de Educación Km. 107 Carretera Tijuana Ensenada B.C. 22860 Mexico
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Gleza, Ivan AtlantNIRO Russia, Kaliningrad, Lugovaya st. 25 Kaliningrad 236029 Russia
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González, Humberto Universidad Austral de Chile Institute of Marine Biology, Campus Isla Teja s/n Valdivia Chile
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Gomez, Fabian Universidad de Concepción Barrio Universitario sin mumero Concepción 4070084 Chile
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González Torres, Macarena Universidad de Las Palmas de Gran Canaria San Vicente Ferrer 11 Villaverde 35640 Spain
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Gomez, Julio Universidad de Las Palmas de Gran Canaria Calle Lila nº 7 2A La Garita Telde 35212 Spain
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Gonzalez-Davila, Melchor Universidad de Las Palmas de Gran Canaria Campus de Tafira Las Palmas de Gran Canaria 35017 Spain
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Gomez, Fernando Centre d’Océanologie de Marseille, CNRS 163 Avenue de Luminy, Case 901 Marseille F-13288 France
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González-Nuevo González, Gonzalo Instituto Español de Oceanografía Avda Principe de Asturias 70 bis Gijón 33212 Spain
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Gómez Cabrera, May Universidad de Las Palmas de Gran Canaria Campus Universitario de Tafira Las Palmas de Gran Canaria 35017 Spain
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Goubanova, Katerina Laboratoire d'Océanographie et du Climat 4 Place Jussieu Paris 75005 France
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Gómez García, Myriam Universidad de Las Palmas de Gran Canaria Juan Carló Nº3 4D Las Palmas de Gran Canaria 35004 Spain
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Goya, Elisa Instituto del Mar del Peru Esq. Gamarra y Gral. Valle s/n, Chucuito, Callao Lima Apartado 22 Peru
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Eastern Boundary Upwelling Ecosystems Symposium Graco, Michelle Ivette Instituto del Mar del Peru Esq. Gamarra y Gral Valle s/n Chucuito Callao 51 Peru
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Guitton, Jerome Agrocampus Rennes IRD Bel Air BP 1386 Dakar 35000 Senegal
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Grados Quispe, Maria del Carmen Instituto del Mar del Peru Esq. Gamarra y Gral Valle s/n Chucuito Callao 51 Peru
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Gutierrez, Dimitri Instituto del Mar del Peru Gamarra y General Valle S/N Chucuito Callao 1 Peru
[email protected] Gutknecht, Elodie Laboratoire d'Etude en Géophysique et Océanographie Spatiale LEGOS - OMP 14 Avenue Edouard Belin Toulouse 31400 France
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Gremillet, David Centre National de la Recherche Scientifique 1919 route de mende Montpellier 34293 France
[email protected] Grigorov, Ivo EUR-OCEANS NoE IUEM, Place Copernic Technopole Plouzane 29280 France
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Hardman-Mountford, Nick Plymouth Marine Laboratory Prospect Place Plymouth PL1 3DH United Kingdom
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Grima, Nicolas Centre National de la Recherche Scientifique Laboratoire de Physique des Ocèans - UBO 6 Avenue le Gorgeu - C.S. 93837 Brest Cedex 3 29238 France
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Heard, Jessica Plymouth Marine Laboratory Prospect Place Plymouth PL1 3DH United Kingdom
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Grote, Britta University of Bremen Leobenerstr. NW2 Marine Zoology FB2 Postfach 330440 Bremen 28359 Germany
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Hernández-Arencibia, Mónica Universidad de Las Palmas de Gran Canaria Campus Universitario de Tafira Edificio de Ciencias Básicas, Laboratorio F-212 Las Palmas de Gran Canaria 35017 Spain
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Gruber, Nicolas Environmental Physics ETH Zurich Universitätstrasse 16 Zurich 8092 Switzerland
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Hernandez-de La Torre, Benigno Instituto Nacional de Ecología (INE-CICESE) Km 107 Carretera Tijuana-Ensenada Casa Móvil No. 8 Ensenada 22860 Mexico
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246
Eastern Boundary Upwelling Ecosystems Symposium Hernández-Guerra, Alonso Facultad de Ciencias del Mar Universidad de Las Palmas de Gran Canaria Las Palmas de Gran Canaria 35017 Spain
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Houssa, Rachida Institut National de Recherche Halieutique 2 Rue Tiznit Casablanca 20200 Morocco
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Hernández-León, Santiago Facultad de Ciencias del Mar Campus Universitario de Tafira Universidad de Las Palmas de GC Las Palmas de Gran Canaria 35017 Spain
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Huang, Bangqin Xiamen University Environmental Science Research Center Xiamen 361005 China (Peoples Republic of)
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Herndl, Gerhard Royal Netherlands Institute P.O. Box 59 Texel NL-1790 AB Den Burg Netherlands
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Huckstadt, Luis University of California Santa Cruz Long Marine Lab 100 Shaffer Rd Santa Cruz 95060 United States of America
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Herrera Rivero, Inmaculada Universidad De Las Palmas De Gran Canaria Campus de Tafira, Ciencias Basicas, B-201 Las Palmas de Gran Canaria 35017 Spain
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Huggett, Jenny Marine & Coastal Management Private Bag X2 Rogge Bay Cape Town 7708 South Africa
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Herrera Ulibarri, Alicia Universidad De Las Palmas De Gran Canaria Salvador Manrique de Lara Nº7 portal 6 escD 2º i Las Palmas, Gran Canaria 35010 Spain
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Hutchings, Larry Marine and Coastal Managment Private Bag X2 Rogge Bay Cape Town 8012 South Africa
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Heymans, Sheila Scottish Assocation for Marine Science Dunstaffnage Marine Laboratory Dunbeg PA371QA United Kingdom
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Iriarte, Jose Universidad Austral de Chile Los Pinos S/N Puerto Montt 1327 Chile
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Hidalgo, Pamela Universidad Austral de Chile P.O.X 160 C- Dichato Concepción 160 Chile
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Ito, Shin-ichi Fisheries Research Agency 3-27-5 Shinhamacho Shiogama 985-0001 Japan
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247
Eastern Boundary Upwelling Ecosystems Symposium Jahncke, Jaime PRBO Conservation Science 3820 Cypress Dr., #11 Petaluma 94954 United States of America
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Kirchner, Carola Ministry of Fisheries and Marine Resources P.O. Box 912 Swakopmund Namibia
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Klein, Eduardo Univ. Simón Bolívar Lab Sensores Remotos Pab 1. USB Caracas 1080 Venezuela
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Jiménez Bordón, Saray Universidad de Las Palmas de Gran Canaria c/ Federico García Lorca 29 Agüimes 35260 Spain
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Kock, Annette IFM-GEOMAR Duesternbrooker Weg 20 Kiel 24105 Germany
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Kaplan, David Institut de Recherche pour le Développement Centre de Recherche Halieutique Avenue Jean Monnet Sète 34203 France
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Kreiner, Anja NatMIRC P.O. Box 912 Swakopmund Namibia
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Karakaş, Gokay Alfred-Wegener-Institute Am Alten Hafen 26 Bremerhaven 27568 Germany
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Kudela, Raphael University of California Santa Cruz Ocean Sciences, 1156 High Street Santa Cruz 95064 United States of America
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Keister, Julie University of Washington 104 COAS Admin Bldg. Corvallis 97330 United States of America
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Kunzmann, Andreas ZMT Bremen Fahrenheitstr. 6 Bremen 28359 Germany
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Kifani, Souad Institut National des Ressources Halieutiques 2 Rue Tiznit Casablanca 20000 Morocco
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Lachkar, Zouhair Federal Institute of Technology Zürich (ETHZ) Inst.f.Biogeochemie u.Schadstoffdynamik CHN E 22, Universitätstrasse 16 Zürich 8092 Switzerland
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King, Gregory Fund. FCUL - Instituto de Oceanografia Campo Grande Lisboa 1749-016 Portugal
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248
Eastern Boundary Upwelling Ecosystems Symposium Lamont, Tarron Marine & Coastal Management Private Bag X2 Rogge Bay Cape Town 8012 South Africa
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Lemos, Ricardo University of Lisbon Rua Carlos Mardel, 111, 2-B Lisbon 1900-120 Portugal
[email protected] Letelier, Jaime Instituto de Fomento Pesquero - IFOP Av. Blanco Encalada 839 Valparaiso 2340000 Chile
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Landeira, Jose Universidad de Las Palmas de Gran Canaria C/Cantillo Abajo, 25,1 Los Realejos 38419 Spain
[email protected] Landry, Michael Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Drive La Jolla 92093-0227 United States of America
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Lett, Christophe Institut de Recherche pour le Développement Institut des Systèmes Complexes - ENS Lyon 46 Allée d'Italie Lyon 69364 France
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Largier, John University of California Davis PO Box 247 Bodega Bay 94923 United States of America
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Levin, Lisa UC San Diego 9500 Gilman Dr. La Jolla 92093-0218 United States of America
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Lathuiliere, Cyril LOCEAN/IPSL, UPMC LOCEAN, case 100, 4 pl. Jussieu Paris Cedex 75252 France
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Linacre, Lorena Universidad Autónoma de Baja California Apartado Postal 453 Ensenada 22800 Mexico
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Lavaniegos, Bertha Centro de Investigación Científica y de Educación km 107 Carretera Tijuana-Ensenada Apdo. Postal 360 Ensenada 22860 Mexico
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Liria Loza, Ana Universidad de Las Palmas de Gran Canaria c/ Lomo la Plana Nº 40, P3 - 1º A Las Palmas de Gran Canaria 35019 Spain
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Lazar, Alban LOCEAN-IPSL / Univ ParisVI UPMC, 4 pl. Jussieu Paris cedex 05 75252 France
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Lluch-Cota, Salvador Northwest Biological Research Center Mar Bermejo 128 Col Playa palo de Santa Rita La Paz 23090 Mexico
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249
Eastern Boundary Upwelling Ecosystems Symposium Lopes, Cristina INETInovação, Marine Geology Estrada da Portela, Zambujal Amadora 2721-866 Portugal
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Manouzi, Hassan Laval University Pavillon Alexandre-Vachon, 1045 av. de la Médecine Local 1074 Quebec G1V 0A6 Canada
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López Hidalgo, Ana María Universidad de Las Palmas de Gran Canaria C/Caracas nº20 Las Palmas de Gran Canaria 35010 Spain
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Marcello, Javier Universidad de Las Palmas de Gran Canaria Edificio B de Electronica y Comunicaciones Campus de Tafira Las Palmas de Gran Canaria 35017 Spain
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Lubchenco, Jane Oregon State University 3029 Cordley Hall Corvallis, Oregon 97331 United States of America
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Marquez, Jose Carlos Instituto del Mar del Peru Esq. Gamarra y Gral. Valle s/n, Chucuito, Callao Lima Apartado 22 Peru
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Machu, Eric Institut de Recherche pour le Développement 2 Rue Tiznit Casablanca 20000 Morocco
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Márquez, Lorenzo IFAPA "Agua del Pino" IFAPA Centro Agua del Pino. P.O. Box 104 Huelva 21071 Spain
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Macias, Diego University of Cadiz Avda. Republica Saharaui s/n CASEM-UCA Puerto Real, 11510 Spain
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Marrero-Díaz, Angeles Universidad de Las Palmas de Gran Canaria Dpto. Física, Ed. Ciencias Básicas. Campus Universitario de Tafira Las Palmas de Gran Canaria 35017 Spain
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Mackas, David Fisheries and Oceans Canada Institute of Ocean Sciences PO Box 6000 Sidney V8L 4B2 Canada
[email protected] Mafwila, Samuel Kakambi University of Namibia Private Bag 13301, Pioneerspark Windhoek Namibia
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Martínez Saavedra, Javier Universidad de Las Palmas de Gran Canaria Ángel Guimerá 96A 4 iz Las Palmas de Gran Canaria 35004 Spain
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Makaoui, Ahmed Institut National des Ressources Halieutiques 2 Rue Tiznit Casablanca 20000 Morocco
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Martínez Sánchez, Ico Universidad de Las Palmas de Gran Canaria Laboratorio B-201 Facultad de Ciencias del Mar Campus Universitario de Tafira Las Palmas de Gran Canaria 35017 Spain
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250
Eastern Boundary Upwelling Ecosystems Symposium Martínez-Marrero, Antonio Universidad de Las Palmas de Gran Canaria Edif. Ciencias Básicas, Campus Universitario Tafira Las Palmas de Gran Canaria 35017 Spain
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Milla Peñaranda, Ruth Instituto del Mar del Peru Las Oxalidas 169 Urb. Las Flores de Lima Dist. San Juan de Lurigancho Lima 36 Peru
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Martins, Rodrigo Marine and Coastal management University of Cape Town Private Bag X2 Roggebay Cape Town, Western Cape 8012 South Africa
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Miñarro Villanueva, Sara Universidad de Las Palmas de Gran Canaria Daoiz, 34, 8-C Las Palmas de Gran Canaria 35010 Spain
[email protected] Moloney, Coleen University of Cape Town Private Bag X3 Rondebosch Cape Town 7701 South Africa
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Mason, Evan Universidad de Las Palmas de Gran Canaria Dept. de Fisica, Campus Universitario Tafira Las Palmas 35017 Spain
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Montecino, Vivian Universidad de Chile Las Palmeras # 3425 Santiago Casilla 653 Chile
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Medina Suárez, Maria Universidad de Las Palmas de Gran Canaria c/ Severo Ochoa 16, 5º A Las Palmas de Gran Canaria 35015 Spain
[email protected] Mendo, Jaime Universidad Nacional Agraria La Molina Av. La Molina s/n Lima 100 Peru
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Monteiro, Pedro Council for Scientific and Industrial Research PO Box 320 Stellenbosch 7599 South Africa
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Menge, Bruce Oregon State University 3029 Cordley Hall Corvallis 97331-2914 United States of America
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Montes, Ivonne Universidad de Concepción Barrio Universitario S/N. Cabina 5. Concepción Casilla 160-C Chile
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Menkel, Jennifer Oregon State University 2030 S.E. Marine Science Dr. Newport 97365 United States of America
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Morales, Jesus IFAPA "Agua del Pino" P.O. Box 104 Huelva 21071 Spain
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Messié, Monique Monterey Bay Aquarium Research Institute 7700 Sandholdt Road Moss Landing 95039 United States of America
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Morales, Carmen Universidad de Concepción Casilla 44 Dichato VIII Chile
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251
Eastern Boundary Upwelling Ecosystems Symposium Moroff, Nadine Everi NatMIRC Ministry of Fisheries & Marine Resources P.O.Box 476 Swakopmund Namibia
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Nevarez Martinez, Manuel Otilio Instituto Nacional de Pesca Calle 20 sur no. 605, col. Centro Guaymas 85400 Mexico
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Moufaddal, Wahid National Institute of Oceanography & Fisheries Qayet-Bey, Al-Anfoushy Alexandria 21556 Egypt
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Nieto, Karen Institut de Recherche pour le Développement - CRH Rue Jean Monnet - BP 171 Sète Cedex 34203 France
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Moyano, Marta Universidad de Las Palmas de Gran Canaria Facultad Ciencias del Mar. Campus de Tafira. Las Palmas de Gran Canaria E-35017 Spain
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Niquen, Miguel Instituto del Mar del Peru Esq. Gamarra y Valle s/n Chucuito - Callao Callao P.O. Box 22 Peru
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Mullon, Christian Institut de Recherche pour le Développement CRH Avenue Jean Monnet Sète 34200 France
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Nuevo Alarcon, Miguel European Commission Champ de Mars 21 3/144 Brussels B-1049 Belgium
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Naik, Hema National Institute of Oceanography Dona Paula 403 004 India
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Nuñez, Samuel University of Concepción Castellon 261 Dpto 202 Concepción 160-C Chile
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Naqvi, Wajih National Institute of Oceanography Dona Paula 403 004 India
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Olaniyan, Micheal Merchant Navy Officers Association 24 Palace Road Olodi Apapa Lagos 2341 Nigeria
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Navarrete, Sergio P. Universidad Catolica de Chile Departamento de Ecología Casilla 114D Santiago Chile
[email protected] Neira, Sergio University of Cape Town Rondebosh 7701 Cape Town 7701 South Africa
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Oliveira, Paulo INRB/L-IPIMAR Av. Brasilia Lisboa 1449-006 Lisboa Portugal
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252
Eastern Boundary Upwelling Ecosystems Symposium Olivera, Humberto Peruvian Marine Research Institute Esquina Gamarra y General Valle S/N, Chucuito Callao 1 Peru
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Parada, Carolina University of Washington Los Aguilera 253C, Barrio Universitario Concepción Chile
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Oliveros-Ramos, Ricardo Pontificia Universidad Católica del Peru Av. Universitaria 1801 San Miguel Lima 32 Peru
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Parrish, Julia University of Washington Box 355020 1122 NE Boat St. Seattle 98195-5020 United States of America
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Orbi, Abdellatif Institut National de Recherche Halieutique 2 Rue Tiznit Casablanca 20000 Morocco
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Patti, Bernardo IAMC-CNR Via L. Vaccara, 61 Mazara del Vallo 91023 Italy
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Ortlieb, Luc Institut de Recherche pour le Développement Centre IRD Ile de France 32 avenue Henri Varagnat Bondy cedex 93143 France
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Paulimier, Aurélien Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS) 18 Avenue Edouard Belin Toulouse 31401 Cedex 9 France
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Ostrowski, Marek Institute of Marine Research Nordnesgaten 50 Bergen 5817 Norway
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Peard, Kathleen Private (ex Ministry of Fisheries Namibia) P.O. Box 2611 Plettenberg Bay 6600 South Africa
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Otero, Pablo Instituto Español de Oceanografía Muelle de Ánimas s/n A Coruña 15001 Spain
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Pedraza Garcia, Milton Jair Universidad de Concepción Cabina 9, Casilla 160-C Concepción Chile
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Otero Villar, Jaime Instituto de Investigaciones Marinas Eduardo Cabello 6 Vigo 36208 Spain
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Pena, Angelica Institute of Ocean Sciences 9860 West Saanich Road PO Box 6000 Sidney V8L 4B2 Canada
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Packard, Theodore, T. Institut Ciències del Mar Passeig de la Marítim de la Barceloneta 37-49 Barcelona 8003 Spain
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253
Eastern Boundary Upwelling Ecosystems Symposium Penven, Pierrick Institut de Recherche pour le Développement Centre IRD de Bretagne B.P. 70 Plouzane 29280 France
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Peterson, William NOAA Fisheries Hatfield Marine Science Center 2030 S Marine Science Drive Newport OR 97365 United States of America
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Perales, Lucia Universidad de Las Palmas de Gran Canaria C/ Secretario Padilla Nº81 2ºL Las Palmas de Gran Canaria 35010 Spain
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Pfaff, Maya University of Cape Town Zoology Dept Private bag X3 Rondebosch Cape Town 7701 South Africa
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Pereira, João Instituto de Investigação das Pescas e do Mar IPIMAR, Av. Brasília, s/n Lisboa 1400-038 Lisboa Portugal
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Piedracoba Varela, Silvia University of Vigo Facultad de Ciencias Lagoas-Marcosende Vigo 36310 Spain
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Pérez Hernández, María Dolores Universidad de Las Palmas de Gran Canaria Salvador Cuyás nº21 Las Palmas de Gran Canaria 35008 Spain
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Pizarro, Oscar University of Concepción Cabina 7, Barrio Universitario s/n. Concepción 4070409 Chile
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Perez Santos, Ivan Ernesto Universidad de Concepción Campus Concepción, Víctor Lamas 1290 Casilla 160C Concepción, Octava Region 4070386 Chile
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Plattner, Gian-Kasper Environmental Physics, ETH Zürich CHN E 21.2 Universitätstr. 16 Zürich CH-8092 Switzerland
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Pesant, Stéphane CNRS - Laboratoire d'Océanographie de Villefranche 181 Rue du Lazaret Villefranche-Sur-Mer 6230 France
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Postel, Lutz Leibniz Institute of Baltic Sea Research Seesstr. 15 Rostock-Warnemünde D 18119 Germany
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Peter, Anne-Charlotte Laboratoire d'Océanographie et du Climat 4 Place Jussieu Paris 75005 France
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Prabhu, C.N. Centre for Marine and Environmental Research Rua dos Bragas, 289 Porto 4050-123 Portugal
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254
Eastern Boundary Upwelling Ecosystems Symposium Purca, Sara Instituto del Mar del Peru Esquina Gamarra y Gral. Valle S/N Callao 1 Peru
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Renault, Lionel Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS) 14 Avenue Edouard Belin Toulouse 31400 France
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Putzeys, Sébastien Universidad de Las Palmas de Gran Canaria Facultad de Ciencias del Mar Tafira Baja 35017 Spain
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Ribeiro, Sofia Faculty of Sciences University of Copenhagen Øster Farimagsgade 2D Copenhagen DK - 1353 Denmark
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Quispe Sanchez, Jorge Research Marine Institute Esq. Gamarra y Gral. Valle s/n Chucuito Callao Callao 51-1 Peru
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Rienecker, Erich Monterey Bay Aquarium Research Institute 7700 Sandholdt Rd Moss Landing 95039 United States of America
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Raimund, Stefan Station Biologique de Roscoff (CNRS) Station Biologique Place Georges Teissier BP 74 Roscoff 29680 France
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Rivera Montaño, Jorge Universidad del Mar Sede Iquique Av. La Tirana 4802 Iquique 56 Chile
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Ramos, Ana Instituto Español de Oceanografía Punta del Apio, San Miguel de Oia Vigo 36200 Spain
[email protected] Ramos, Vito Instituto Canario de Ciencias Marinas ICCM carretera de Taliarte s/n Telde 35200 Spain
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Rizzo Aparicio, Pilar Universidad de Las Palmas de Gran Canaria Campus de Tafira, Edificio de Ciencias Básicas Las Palmas de Gran Canaria 35017 Spain
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Ramzi, Azeddine Institut National de Recherches Halieutiques 2 Rue Tiznit Casablanca 20 000 Morocco
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Roa Pascuali, Carmen Liliana Universidad de Las Palmas de Gran Canaria Salvador Marrique de Lara 7 p.6 Esc. Derecha 2 izq Las Palmas de Gran Canaria 35010 Spain
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Relvas, Paulo Univ. Algarve - CIMA FCMA - Campus de Gambelas Faro 8005-139 Portugal
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Roberts, David Council for Geoscience Po Box 572 Bellville 7535 South Africa
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255
Eastern Boundary Upwelling Ecosystems Symposium Rodhe, Johan University of Gothenburg Po Box 469 Gothenburg 40560 Sweden
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Rossi, Vincent CNRS/LEGOS 14 Avenue Edouard Belin Toulouse 31400 France
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Rodrigo Mora, Miguel Universidad de Las Palmas de Gran Canaria c/Camilo José Cela nº-2 Duplex M-2 35017 El Fondillo-Tafira Baja Las Pamas de Gran Canaria 35017 Spain
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Roux, Jean-Paul Ministry of Fisheries and Marine Resources PO Box 394 Luderitz Namibia
[email protected] Roy, Claude Institut de Recherche pour le Développement Centre Ifremer de Brest BP 70 Plouzané 29280 France
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Rodrigues Vera, Gabriela University of São Paulo Praça do Oceanográfico, 191 São Paulo Brazil
[email protected] Rodriguez, German Universidad de Las Palmas de Gran Canaria Edificio de Ciencias Básicas, Dpto de Física Las Palmas de Gran Canaria 35017 Spain
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Rubio, Anna LPO - UBO Laboratoire de Ohysique des Océans 6, Avenue le Gorgeu CS93837 Brest 29238 France
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Rodríguez, José María Instituto Español de Oceanografía Avda. Príncipe de Asturias 70Bis Gijón 33212 Spain
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Ruiz Villarreal, Manuel Instituto Español de Oceanografía Muelle de Ánimas A Coruña 15001 Spain
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Rodríguez Ucha, Iván Universidad de Las Palmas de Gran Canaria Campus de Tafira, Edificio de Ciencias Básicas Las Palmas de Gran Canaria 35017 Spain
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Rutllant, Jose Universidad de Chile Blanco Encalada 2002 Santiago 837-0449 Chile
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Rodriguez-Sanchez, Ruben CICIMAR Av. IPN s/n Col. Palo de Sta. Rita La Paz 23090 Mexico
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Ryan, John Monterey Bay Aquarium Research Institute 7700 Sandholdt Road Moss Landing 95039 United States of America
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Romera Castillo, Cristina Instituto de Investigaciones Marinas Passeig maritim de la Barceloneta, 37-49 Barcelona 8003 Spain
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256
Eastern Boundary Upwelling Ecosystems Symposium Rykaczewski, Ryan University of California, San Diego 9500 Gilman Dr. MC 0208 La Jolla 92093 United States of America
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Santamaría, Mª Teresa Instituto Español de Oceanografía Avenida 3 de Mayo nº 73 - Edificio Sanahuja 38005 Santa Cruz de Tenerife Spain
[email protected] Santana-Casiano, J. Magdalena Universidad de Las Palmas de Gran Canaria Campus de Tafira Las Palmas de Gran Canaria 35017 Spain
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Sabarros, Philippe University of Oslo Centre for Ecological and Evolutionary Synthesis PO Box 1066 Blindern Oslo 316 Norway
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Santander, Edgardo Universidad Arturo Prat Avenida Arturo Prat 2120 Iquique 121 Chile
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Salgueiro, Emilia University of Chicago 5734 S. Ellis Avenue Chicago 60637 United States of America
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Santos, A Miguel INRB-IPIMAR Av. Dr. Alfredo Magalhães Ramalho s/n Lisboa 1449-006 Portugal
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Salinas Nuñez, Carolina Universidad de Las Palmas de Gran Canaria benecharo 14 piso 1 casa derecha Las Palmas de Gran Canaria 35009 Spain
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Schmoker, Claire Universidad de Las Palmas de Gran Canaria Facultad de Ciencias del Mar Campus Universitario de Tafira Las Palmas de Gran Canaria 35017 Spain
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Salvanes, Anne Gro Vea University of Bergen Museplass 1 Bergen 5020 Norway
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Schwamborn, Ralf Alfred Wegener Institute for Polar and Marine Research Am alten Hafen 26 Bremerhaven 27568 Germany
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Samarajalingam, Shanmuganandan Madurai Kamaraj University Department of Geography School of Earth & Atmospheric Science Madurai 625021 India
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Segovia Zavala, Jose Antonio UABC Km 103 Carretera Tijuana- Ensenada Unidad Universitaria UABC Ensenada 22830 Mexico
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Sánchez-Sánchez, Gloria Universidad de Concepción Barrio Universitario SN Concepción Chile
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Eastern Boundary Upwelling Ecosystems Symposium Serrats, Garcia Universidad de Las Palmas de Gran Canaria c/Peru43 2A Las Palmas de Gran Canaria 35010 Spain
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Sobrinho-Gonçalves, Luís André Instituto de Investigação das Pescas e do Mar Av. Brasília Lisboa 1449-006 Portugal
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Shannon, Lynne Marine and Coastal Management Private Bag X2 Rogge Bay Cape Town 8012 South Africa
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Solari, Aldo Universidad de Las Palmas de Gran Canaria Instituto Español de Oceanografía Centro Ocean. de Canarias AV. 3 de Mayo Nº 73 SC de Tenerife 38005 Spain
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Shaw, Caroline Oregon State University 2030 SE Marine Science Drive Newport 97365 United States of America
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Sørensen, Lise Lotte National Environmental Research Institute Frederiksborgvej 399 Roskilde 4000 Denmark
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Shillington, Frank Department of Oceanography University of Cape Town Rondebosch 7701 South Africa
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Soto-Maredones, Luis Universidad Del Bio Bio Casilla 5-C Concepción Chile
[email protected] Sow, Bamol Ali University of Ziguinchor LPA/ESP BP 5085 Dakar-Fann Dakar 11524 Senegal
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Shin, Yunne-Jai Institut de Recherche pour le Développement Avenue Jean Monnet, BP 171 Sète 34203 France
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Sidibe, Aboubacar Sub Regional Fisheries Commission Amitié 3, Villa 4430 Dakar BP 25485 Senegal
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Spyrakos, Evangelos University of Vigo As Lagoas Marcosende Fac. Sciencias Vigo 36310 Spain
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Sifeddine, Abdelfettah Institut de Recherche pour le Développement 32. Avenue Henri Varagnat Bondy 93143 France
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Staby, Arved University of Bergen P O Box 7803 Bergen 5020 Norway
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Eastern Boundary Upwelling Ecosystems Symposium Strub, P. Ted Oregon State University 104 COAS Admin Bldg Corvallis 97331-5503 United States of America
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Thomas, Andrew University of Maine Aubert Hall Orono 4469 United States of America
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Tapia, Fabian Pontificia Universidad Catolica de Chile Casilla 114-D Santiago 6513677 Chile
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Tjizoo, Mbeurora Beau Ministry of Fisheries and Marine Resources Box 912 Strand street Swakopmund Namibia
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Tapia, Pedro Instituto del Mar del Peru Esquina Gamarra y Gral Valle s/n Chucuito Callao Callao 5 Peru
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Torres, Jesus University of Vigo Lagoas-Marcosende Vigo 36310 Spain
[email protected] Torres, Carlos R. Universidad Autonoma de Baja California Km 107 Carr. Tijuana-Ensenada Ensenada 22800 Mexico
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Teixeira, Isabel Instituto de Investigaciones Marinas Eduardo Cabello, 6 Vigo 36208 Spain
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Torres Palenzuela, Jesus University of Vigo Fac. Ciencias del Mar. Lagoas-Marcosende Dep. Física Aplicada Vigo 36310 Spain
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Teles-Machado, Ana Universidade de Aveiro Departamento de Física da Universidade de Aveiro Campus Universitário de Santiago, 3810-193 Aveiro Aveiro 3810 Portugal
[email protected] Tersa Sotke, Elena Universidad de Las Palmas de Gran Canaria C/ Italia Nº 15 Valle Gran Rey (La Gomera) 38870 Spain
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Trasvina Castro, Armando Centro de Investigación Científica y de Educación Miraflores 334 e/Mulegé y La Paz; Fracc. Bella Vista La Paz 23040 Mexico
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Thiaw, Modou Institut de Recherche pour le Développement IRD Bel Air Dakar (Senegal) Dakar 1386 Senegal
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Travers, Morgane Institut de Recherche pour le Développement Avenue Jean Monnet BP 171 Sète 34200 France
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259
Eastern Boundary Upwelling Ecosystems Symposium Troupin, Charles University of Liège Building B5a Allée du 6 Août, 17 Liège 4000 Belgium
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van Zyl, Ben Ministry of Fisheries and Marine Resources Strand Street Swakopmund 9000 Namibia
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Veitch, Jennifer University of Cape Town Department of Oceanography Rondebosch 7701 South Africa
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Trudel, Marc Fisheries and Oceans Canada 3190 Hammond Bay Road Nanaimo V9T 6N7 Canada
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Trujillo Santana, Aarón Universidad de Las Palmas de Gran Canaria Campus Universitario de Tafira, s/n edif. Ciencias Básicas, Ciencias del Mar, B-203.1 Las Palmas de Gran Canaria 35017 Spain
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Verley, Philippe Institut de Recherche pour le Développement 2 Impasse du Théven Blanc Sablon Le Conquet 29217 France
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Ugía García, Juan Manuel Universidad de Las Palmas de Gran Canaria C/Pérez de toro 43 1º Izq Las Palmas de Gran Canaria 35004 Spain
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Villegas, Mario Universidad Arturo Prat Av. Arturo Prat 2120 Casilla 121 Iquique 1101535 Chile
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Uumati, Martha University of St Andrews 55 Albany Park, St Mary str. St Andrews KY16 9BP United Kingdom
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Voelker, Antje Laboratorio Nacional de Energia e Geologia Estrada da Portela, Zambujal Alfragide 2721-866 Portugal
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van der Lingen, Carl Marine and Coastal Management Private Bag X2, Rogge Bay Cape Town 8012 South Africa
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Wallace, Douglas IFM-GEOMAR Düsternbrooker Weg 20 Kiel 24105 Germany
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van Oordt, Francis Instituto del Mar del Peru Esq. Gamarra y Gral Valle Callao Peru
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Wieters, Evie Pontificia Universidad Catolica de Chile La Alameda 340 Santiago Chile
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Eastern Boundary Upwelling Ecosystems Symposium Wolff, Matthias Charles Darwin Foundation, Galapagos Puerto Ayora, Santa Cruz PO Box 17-1-389 Quito-Ecuador Ecuador
[email protected] Yanez, Eleuterio Catholic University of Valparaiso Avenida Altamirano 1480 Valparaiso 1020 Chile
[email protected] Yannicelli, Beatriz Centro de Estudios Avanzados en Zonas Áridas Facultad de Ciencias del Mar Universidad Católica del Norte (campus Guayacan) Larrondo 1281 Coquimbo Chile
[email protected] Yataco, Gisella Instituto del Mar del Peru Esq. Gamarra y Gral. Valle s/n, Chucuito, Callao Lima Apartado 22 Peru
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Eastern Boundary Upwelling Ecosystems Symposium
Author index A
Barrera Luján, A.......................................... 209 Barriga, C.................................................... 224 Barriga, E.................................................... 100 Barth, J........................................................ 127 Bartholomae, C..................................... 41, 100 Barton, E.D.. 40, 49, 54, 75, 106, 140, 164, 190 Bas, C.......................................................... 105 Basilone, G.................................................... 53 Batteen, M................................................... 106 Bauleth-D’Almeida, G.................................... 98 Beckers, J-M................................................ 125 Bécognée, P................................................ 138 Beibou, E....................................................... 99 Beillois, P..................................................... 204 Belghyti, D..................................................... 95 Bel Madani, A.......................................... 62, 67 Benazzouz, A........................................ 76, 151 Ben cherifi, S............................................... 207 Bendtsen, J................................................. 109 Ben-Hamadou, R......................................... 197 Benitez-Barrios, V.M.................................... 109 Bentamy, A.................................................. 133 Bernal, M............................................. 108, 204 Berraho, Am................................................ 185 Bertrand, A.................... 46, 117, 179, 198, 201 Bertrand, S............................................ 97, 217 Bester, M.N.................................................. 218 Biccard, A.................................................... 135 Bissett, P...................................................... 175 Blanchette, C................................. 48, 160, 164 Blanco, J.L..................................................... 54 Blanke, B..................................... 130, 133, 228 Blasco, D..................................................... 146 Bode, A.................................................. 62, 127 Bograd, S...................................................... 78 Bonanno, A.................................................... 53 Böning, C..................................................... 120 Boom, A......................................................... 71 Borges, M.F................................................... 63 Boris, D........................................................ 110 Bosc, C.......................................................... 63 Bo, T............................................................ 149 Boucharel, J........................................... 63, 111 Boucher, H..................................................... 79 Bouloubassi, I.......................................... 59, 82 Boussafir, M................................................... 79 Boyra, G...................................................... 204 Bradley, R...................................................... 92 Branch, G............................ 135, 156, 160, 161 Braun, M........................................ 67, 208, 210 Brickley, P...................................................... 74 Brochier, T............................ 198, 205, 228, 230 Bröhl, S........................................................ 172 Broitman, B............................................ 48, 160 Brüchert, V................................................... 142 Brunet, C..................................................... 167 Buchholz, F.......................................... 180, 189 Bueno, J...................................................... 181 Burgos, C.................................................... 169 Buscaino, G................................................... 53
Abrantes, F............................ 57, 70, 79, 86, 89 Acuña, A........................................................ 89 Agostini, V.................................................... 201 Aguero, M...................................................... 97 Aguilera-Rodà, M................................ 163, 223 Aguirre, E.................................................... 228 Aguirre-Gómez, R....................................... 151 Agujetas, J..................................................... 81 Aiken, J.......................................................... 75 Aita, M......................................................... 227 Aksissou, M................................................. 204 Alarcón, G................................................... 178 Albert, A....................................................... 134 Alcaraz, M................................................... 152 Alheit, J.................................................. 49, 202 Almeida, C........................................... 138, 187 Alonso-González, I.J................................... 134 Alonso-Pérez, F........................................... 142 Alonso-Sáez, L............................................ 167 Altwegg, R................................................... 219 Álvarez, E.............................................. 84, 181 Alvarez-Ossorio, M.T..................................... 62 Álvarez-Salgado, X.A.. 40, 58, 81, 95, 165, 166 Alves, J.......................................................... 61 Alza, L......................................... 215, 219, 225 Amigoni, E..................................................... 79 Ammerman, J.............................................. 146 Amorim, A...................................................... 70 Anabalón, V................................................. 178 Angélico, M.......................................... 163, 204 Antezana, T.......................................... 168, 205 Aramayo, V.................................................. 148 Arancibia, H................................................... 52 Arbones, B........................................... 142, 176 Arias Schreiber, M....................................... 223 Arístegui, J.. 38, 40, 46, 134, 145, 167, 176, 179 Arreguin-Sanchez, F.............................. 94, 221 Arteaga, L...................................................... 51 Atillah, A........................................................ 76 Auel, H......................................................... 178 Aumont, O............................................. 94, 134 Aveytua-Alcázar, L....................................... 158 Axelsen, B................................................... 183 Ayón, P................ 169, 172, 173, 174, 181, 184
B
Bahlo, R....................................................... 142 Baisnée, P-F.................................................. 47 Bakun, A........................................................ 56 Balguerías, E............... 103, 105, 169, 213, 214 Ballón Soto, M............................................. 179 Baltar, F....................................................... 179 Bange, H.............................................. 111, 118 Banks, S........................................................ 61 Barange, M............................................ 38, 201 Barber, R..................................................... 146 Barlow, R............................................. 171, 190 Barreiro, A..................................................... 53 Barrera, A.................................... 206, 213, 214
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Eastern Boundary Upwelling Ecosystems Symposium
C
Conversano, F............................................. 167 Cordova, J................................................... 211 Cornejo, M........................................... 136, 143 Correa, D................................................. 62, 77 Cosío, M.A..................................................... 54 Costa, D...................................................... 220 Costas, G.................................................... 204 Crato, N......................................................... 63 Cravo, A....................................................... 136 Crawford, R........................... 46, 219, 221, 225 Crespo, B............................................ 184, 194 Criales-Hernandez, M.I....................... 173, 174 Cristobo, F.J................................................ 169 Crosnier, L................................................... 113 Cruz-Escalona, V.H..................................... 221 Cruz, J......................................................... 182 Cuadra, D'L................................................. 148 Cubillos, L............................ 104, 206, 207, 208 Cunha, E............................................. 193, 197 Currie, B.......................................... 41, 96, 142 Currie, J......................................................... 63 Cury, P............................................. 91, 92, 232 Cuttitta, A....................................................... 53
Cabal, E......................................................... 84 Cabal Naves, J............................................ 181 Cabanas, J.M.......................................... 58, 62 Cabello-Pasini, A......................................... 153 Cahuin,S.M.................................................. 206 Caiado, J....................................................... 63 Calabuig Miranda, P.................................... 223 Caldentey, P................................................. 206 Calvo-Díaz, A.............................................. 127 Camacho-Íbar, V.................................. 153, 158 Capet, X.......................... 47, 50, 107, 133, 198 Caquineau, S................................................. 79 Cardeira, S.................................................. 136 Carlos Gutiérrez, J...................................... 233 Carlos Marquez, J....................................... 217 Carr, A........................................................... 71 Caselle, J..................................................... 164 Casotti, R..................................................... 167 Castilla, J..................................................... 157 Castillo, J..................................................... 125 Castillo-Jordán, C................................ 207, 208 Castillo, M.................................................... 157 Castillo, R............................................ 169, 184 Castro, C............................................... 78, 142 Castro, J.............................................. 103, 105 Castro, L.............................................. 207, 230 Castro, N..................................................... 163 Cauquil, P...................................................... 99 Cazassus, F......................................... 172, 181 Cepeda-Morales, J........................................ 66 Chaigneau, A............ 62, 67, 112, 116, 117, 201 Chan, F........................................................ 157 Chang, B..................................................... 143 Chang, N............................... 70, 133, 135, 231 Charouki, N................................................... 95 Charria, G.................................................... 113 Chavance, P.................................................. 99 Chavez, F................................ 43, 78, 145, 175 Checkley, D....................................... 41, 46, 93 Chelton, D.B................................................ 107 Chen, J................................................ 182, 188 Chernyshov, P................................................ 76 Chfiri, H........................................................ 203 Chícharo, A.................................................. 197 Chlaida, M................................................... 207 Chollett, I....................................................... 51 Christensen, J.C.......................................... 146 Christensen, V............................................... 99 Christiansen, M.B........................................ 109 Cianca, A....................................................... 87 Claramunt, G....................................... 207, 208 Cobas-Garcia, M......................................... 159 Cobas, M..................................................... 108 Coble, P....................................................... 146 Coca, J........................................................ 122 Codispoti, L......................................... 141, 146 Coetzee, J........................................... 172, 201 Colas, F......... 47, 107, 108, 114, 120, 133, 198 Colin de Verdiere, A..................................... 227 Collins, C....................................................... 78 Coll, M........................................................... 46 Conde, P...................................................... 108
D
Dadou, I................................................ 113, 118 Dagmar, W................................................... 149 Dagorne, D........................................ 47, 82, 83 Dandonneau, Y............................................ 115 Daneri, G............................................. 187, 189 Da Silva, A........................................... 173, 183 D'Croz, L...................................................... 137 de Abreu, L.................................................... 73 de Bruyn, P.J.N............................................ 218 de Fátima Borges, M................................... 137 De-la-Cruz, M................................................ 66 Delgadillo Hinojosa, F.................................. 154 Del Monte-Luna, P....................................... 221 Demarcq, H........................... 52, 53, 76, 82, 83 De Ponte Machado, M................................. 216 Devis-Morales, A......................................... 114 Devol, A....................................................... 143 Dewitte, B....... 62, 63, 64, 67, 77, 116, 117, 133 Dias, J........................................................... 85 Díaz Cordero, J........................................... 214 Dimier, C...................................................... 167 DingsØr, G..................................................... 95 Domingos, I................................................. 163 Dominguez, N.............................................. 138 Donoso, D................................................... 114 Donoso, K.................................................... 183 Dopolo, M.................................................... 183 dos Santos, A.............................................. 182 Drapeau, L............................................... 82, 83 Drévillonm, M............................................... 113 Dubert, J................................................ 71, 128 Dugdale, R.C............................................... 146 du Penhoat, Y......................... 63, 110, 111, 116 Duque, V...................................................... 214 Durant, J...................................................... 225 Durazo-Arvizu, R................................. 153, 158 Durazo, R................................................ 54, 64 Duteil, O...................................................... 115
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E
Franco, C..................................................... 204 Franklin, D................................................... 185 Freing, A............................................... 111, 118 Frenzel, H........................................ 44, 45, 132 Fréon, P..................................... 38, 46, 47, 198
Echevarría, F............................................... 115 Echevin, V.. 62, 64, 67, 111, 116, 117, 119, 133, 134, 145, 198 Eden, C....................................................... 117 Eiroa, A................................................ 163, 223 Ekau, W............................................... 172, 188 Eldin, G................................. 111, 112, 116, 117 El hafa, M.................................................... 212 Elkalay, K..................................................... 232 Ellegaard, M.................................................. 70 Elliott, M......................................................... 92 EL Ouizgani, H............................................ 209 Elwazzani, H................................................ 203 El Yazidi, B.................................................. 204 Emeis, K-C.................................................. 142 Endler, R...................................................... 142 Enríquez, E.................................................. 148 Escalera, L.................................................. 159 Escribano, R.. 129, 144, 172, 178, 181, 183, 191, 206 Escudero, Y......................................... 169, 184 Espíndola, F................................................. 210 Espino, M............................................ 134, 179 Espinoza, O........................................... 81, 184 Espinoza, P.................................................. 198 Estrada, M................................................... 146 Estrade, P.................................................... 227 Estrella Alcaman, M..................................... 148 Ettahiri, O............................................ 185, 207 Eugenio, F..................................................... 68 Ezer, T............................................................ 88
G
Gaines, S............................................. 157, 160 Galan, A....................................................... 149 Gallegos, M................................. 136, 148, 150 Gallegos, P.................................................... 65 Garabana, D................................................ 204 García, C............................................. 115, 213 García, E..................................................... 169 García, M....................................................... 79 García-Muñoz, M......................................... 179 García-Weil, L.............................................. 122 Garçon, V........ 43, 113, 118, 121, 123, 139, 153 Garel, B......................................................... 63 Garreaud, R................................................... 56 Garrido, S.................................................... 197 Gascuel, D..................................................... 72 Gasol, J............................................... 167, 179 Gatica, C..................................................... 104 Gaute, L....................................................... 149 Gaxiola-Castro, G.................................. 66, 151 Gebhardt, S.......................................... 111, 118 Ghebrehiwet, D................................... 167, 229 Gibbons, M.................................................... 46 Giese, B......................................................... 77 Giglio, S....................................................... 186 Glessmer, M................................................ 117 Gleza, I.......................................................... 76 Goericke, R................................................. 175 Gómez, J....................................................... 84 Gómez, M.................... 146, 152, 186, 187, 233 Gomez-Valdes, J........................................... 66 Gómez-Valdivia, F........................................ 117 Gonález Pola, C.......................................... 107 González, A................................................. 122 González-Dávila, M............................... 88, 124 González, E................................................... 54 González-Fernández, Á................................ 89 González, H................................. 186, 187, 189 González, J................................. 101, 213, 214 González, M................................................ 169 González-Nuevo, G................. 84, 95, 108, 181 González, P................................................. 178 González Pola, C........................................ 127 Gotchalk, C.................................................. 164 Goubanova, K............................................... 67 Gourich, H................................................... 203 Gower, J...................................................... 175 Goya, E....................................................... 221 Graco, M...................................................... 150 Grados, C..................................... 112, 116, 117 Grémillet, D.................................................. 217 Grigorov, I...................................................... 94 Grima, N.............................................. 130, 133 Groom, S....................................................... 81 Grote, B....................................................... 188 Gro Vea Salvanes, A............................. 96, 199 Gruber, N................................. 44, 45, 132, 145
F
Fairweather, T...................................... 172, 219 Falvey, M....................................................... 56 Faraj, A.................................. 51, 103, 169, 231 Färber Lorda, J.............................................. 50 Farías, L.............................. 136, 143, 148, 150 Faundez, J................................................... 143 Feinberg, L.................................................. 193 Fernández, C....................................... 143, 148 Fernández, L....................... 7, 51, 68, 103, 104 Fernández Reiriz, M.J........................... 58, 165 Fernø, A....................................................... 199 Fewings, M.................................................. 164 Fidel, Q.......................................................... 41 Fiedler, B....................................................... 83 Fiedler, P........................................................ 50 Field, D.................................................... 56, 59 Field, J........................................................... 46 Field, J.G............................................. 167, 229 Figueiras, F.. 40, 58, 81, 142, 159, 176, 184, 194 Filgueira, R............................................ 58, 165 Fischer, A..................................................... 175 Fischer, G............................................ 129, 229 Fisher, J....................................................... 161 Flores, G...................................................... 150 Flores, J.A..................................................... 86 Fonte, A......................................................... 68 Foreman, M................................................. 230 Fraile-Nuez, E............................................. 120
264
Eastern Boundary Upwelling Ecosystems Symposium Guisande, C............................................ 53, 89 Guitton, J....................................................... 99 Gurgel, M....................................................... 79 Gutiérrez, D............... 59, 79, 82, 148, 150, 154 Gutierrez, M......................................... 179, 201 Gutknecht, E......................................... 113, 118
Jimenez, C.................................................... 86 Jiménez, M.................................................. 204 Jin, X........................................................... 107 Joubert, W.R................................................ 141 Jouffre, D............................................... 72, 105 Jourdin, F............................................. 121, 139 Juliano, M...................................................... 85
H
K
Habasque, J........................................ 117, 201 Hagen, W..................................................... 188 Halle, C........................................................ 162 Hamady, B................................................... 211 Harang, A.................................................... 117 Hardman-Mountford, N.J............................... 75 Hashioka, T.................................................. 227 Hassrick, J................................................... 220 Hebbeln, D.................................................... 69 Henry, W...................................................... 220 Hernández-Ayón, J.M.................. 153, 158, 191 Hernández, C........................................ 51, 103 Hernández-de la Torre, B............................ 151 Hernández, E.............................................. 169 Hernandez-Garcia, E..................................... 43 Hernández-Guerra, A.............. 40, 68, 109, 120 Hernández-León, S.. 40, 69, 84, 109, 128, 138, 172, 187, 190, 192, 200, 206, 209 Hernández-Walls, R.................................... 151 Herndl, G..................................................... 179 Herrera-Cervantes, H.................................... 78 Herrera Rivero, I.......................................... 209 Herrero, J.................................................... 140 Heymans, J................................................... 99 Hidalgo, P.................................... 129, 144, 191 Hilligsøe, K.M.............................................. 109 Hill, K........................................................... 201 Hilmi, K.................................................. 76, 151 Hirata, T......................................................... 75 Hirche, H-J................................................... 173 Hong, H....................................................... 188 Hormazabal, S.E................................... 90, 129 Houssa, R.................................... 185, 203, 209 Huang, B............................................. 182, 188 Huckstadt, L................................................ 220 Huggett, J............................................ 172, 181 Hu, J............................................................ 188 Hutchings, L.............. 41, 46, 63, 172, 200, 201
Kaplan, D..................................................... 162 Kappes, M................................................... 220 Karakaş, G.......................................... 129, 229 Keister, J...................................................... 131 Kemper, J...................................................... 60 Khalil, K....................................................... 232 Kifani, S................................... 40, 76, 207, 209 King, G.......................................................... 85 King, S......................................................... 175 Kirchner, K................................................... 100 Kirkman, S........................................... 218, 219 Kishi, M........................................................ 227 Klein, E.......................................................... 51 Kock, A................................................. 111, 118 Kolber, D...................................................... 145 Körtzinger, A........................................... 83, 111 Koslow, A..................................................... 176 Krakstad, J.O................................................. 76 Kreiner, A....................... 41, 172, 173, 181, 210 Kudela, R............................................. 159, 175 Kuhn, C....................................................... 220 Kunzmann, A............................................... 189 Kuypers, M.................................................. 150 Kyewalyanga, M.................................. 171, 190
L
Labarta, U.............................................. 58, 165 Lachkar, Z...................................... 44, 132, 145 Lago de Lanzós, A....................................... 204 Lakhnigue, A........................................ 203, 209 Lamont, T............................................. 171, 190 Landeira, J................................................... 190 Landry, M............................................. 175, 191 Lange, C.................................................. 42, 69 Lara-Lara, R................................................ 191 Lares Reyes, M.L........................................ 154 Largier, J...................... 156, 157, 161, 162, 164 Larissi, J................................................ 76, 151 Lathuiliere, C............................................... 119 Laudien, J...................................................... 72 Lavaniegos, B................................................ 67 Lavik, G....................................................... 150 Lavín, A............................................... 107, 127 Lavín, M......................................................... 50 Lazar, A............................................... 115, 121 Lebourges-Dhaussy, A................................ 179 Ledesma, J................... 116, 117, 134, 145, 201 Lemos, R....................................................... 85 Leslie, R...................................................... 167 Letelier, J............................... 67, 101, 210, 211 Letelier, R...................................................... 55 Lett, C.................................. 198, 205, 228, 231 Levenez, J................................................... 212
I
Ibaibarriaga, L............................................. 204 Iglesias, M................................................... 204 Indacochea, A.............................................. 165 Iriarte, J............................................... 187, 189 Ito, S-I.......................................................... 227
J
Jahncke, J..................................................... 92 Jarre, A.......................................... 47, 171, 232 Jaziri, H........................................................ 207 Jeronimo, G................................................... 66 Jesús, L....................................................... 150 Jiménez Bordón, S...................................... 224
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Eastern Boundary Upwelling Ecosystems Symposium Lévy, M................................................ 119, 134 Linacre, L..................................................... 191 Lin, L............................................................ 182 Lino Costa, J............................................... 163 Liria Loza, A......................................... 223, 224 Liu, X........................................................... 182 Liu, Y.............................................................. 55 Llinás, O........................................................ 87 Lluch-Belda, D............................................... 78 Lluch-Cota, S................................................. 78 Loeza, I........................................................ 221 Loher, D........................................... 44, 45, 132 Lopes, C.................................................. 57, 79 López Abellán, L.J............................... 213, 214 López, C...................................................... 214 López-Jurado, L.F........................ 163, 223, 224 López-Laatzen, F......................................... 120 López, O.............................................. 163, 223 Loudiki, M.................................................... 232 Lourenço, S................................................. 137 Louw, D................................................. 41, 171 Lozano Soldevilla, F.................................... 190 Lucas, M........................................................ 63 Lwiza, K.M.M............................................... 109
Mazzola, A..................................................... 53 McWilliams, J.C................................... 107, 132 Mecenero, S................................................ 218 Medina Suárez, M....................................... 224 Megrey, B.................................................... 227 Meiners, C............................... 51, 68, 104, 169 Méjanelle, L............................................. 59, 82 Mejía-Trejo, A...................................... 153, 158 Mélice, J-L................................................... 141 Mélin, F.......................................................... 76 Mendes, H..................................................... 63 Mendo, J...................................................... 194 Meneses, I................................................... 163 Menge, B..................................................... 157 Menkel, J..................................................... 192 Menschel, E................................................. 187 Mesfoui, H................................................... 169 Messié, J..................................................... 145 Messie, M...................................................... 43 Miguel Santos, A......................................... 182 Millán, M...................................................... 204 Miller, H........................................................ 106 Miquel Batle, J............................................. 181 Miranda, A..................................................... 62 Miranda, P...................................................... 61 Mitchell-Innes, B.......................................... 171 Mitchelson-Jacob, G...................................... 81 Miz, A.C......................................................... 57 Mohamed Mahmoud, E............................... 211 Moita, T........................................ 159, 160, 193 Molemaker, J....................................... 107, 108 Moloney, C....................... 47, 92, 171, 231, 232 Montecino, V.......................................... 42, 123 Monteiro, P................................................... 141 Montero, M.......................................... 134, 179 Montes, I...................................................... 120 Montoya, R.................................................. 114 Morales, C........................................... 129, 178 Morales, J................................................ 86, 87 Morales-Zárate, M......................................... 78 Morel, Y........................................ 121, 123, 139 Moreno, A.................................................... 137 Morin, P................................................ 121, 139 Morón, O..................................... 138, 150, 202 Mosquera Giménez, Á................................... 89 Mouritsen, L................................................. 109 Moyano, M............................................. 69, 128 Mueller, J..................................................... 125 Muller-Karger, F............................................. 88 Mullon, C................... 46, 47, 92, 198, 228, 230
M
Machín, F..................................................... 125 Machu, E....................... 40, 133, 145, 185, 231 Macías, D.................................................... 115 Mackas, D..................................................... 60 Madec, G..................................................... 119 Madureira, M............................................... 136 Makaoui, A............................................. 76, 151 Makhado, A................................................. 219 Malin, G....................................................... 185 Maneiro, I...................................................... 53 Manríquez, K....................................... 183, 191 Manuel Cabanas, J..................................... 107 Manzano, M................................................. 200 Marcel, K..................................................... 149 Marcello, J..................................................... 68 Marchant, M.......................................... 69, 186 Marchesiello, P.............. 47, 124, 133, 227, 229 Marhoum, A................................................. 203 Marques, V.......................................... 163, 204 Márquez, J.C............................... 219, 223, 224 Marquez, L.................................................... 86 Marquina, R................................................. 148 Marrasé, C................................................... 166 Martinez-Aguilar, S........................................ 94 Martínez-Gaxiola, M.................................... 151 Martinez, I.................................................... 186 Martínez-Marrero, A.................................... 120 Martinho, A.......................................... 106, 139 Martin, P......................................................... 89 Martins, R.................................................... 231 Mason, E............................... 40, 108, 126, 205 Masotti, I...................................................... 153 Massé, J...................................................... 204 Masski, H....................................................... 46 Masumbuko, B.............................................. 99 Mata, A.J....................................................... 86 Mazumder, A................................................. 60
N
Nagai, T....................................................... 132 Naqvi, S.W.A............................................... 146 Navarrete, S................................ 157, 160, 161 Navarro, E................................................... 104 Neira, S..................................... 47, 52, 92, 232 Nevárez Martínez, M................................... 212 Nieto Cid, N................................................. 166 Nieto, K.................................................... 52, 53 Ñiquen, M............................................ 202, 213 Nissesn, J.................................................... 109 Nogueira, E................................... 84, 181, 204
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Eastern Boundary Upwelling Ecosystems Symposium Nolasco, R................................................... 128 Nowald, N.................................................... 129 Nunes, C............................................. 163, 204 Núñez-Ricardo, S.......................................... 69 Nuñez, S...................................................... 129
Pitcher, G..................................................... 159 Pizarro, M...................................................... 67 Pizarro, O............................................ 178, 186 Planes, S..................................................... 207 Plattner, G-K.................................... 44, 45, 132 Plaza, F........................................................ 233 Postel, L.............................................. 173, 183 Poulton, A.................................................... 185 Prabhu, C.N................................................... 86 Presas, C............................................... 51, 214 Pulido, I....................................................... 233 Purca, S................................................... 64, 77 Putzeys, S................................................... 138
O
Oakka, K...................................................... 203 O'Dea, A...................................................... 137 Ohman, M.................................................... 175 Okunishi, T................................................... 227 Oliveira, P.................................... 128, 160, 163 Olivera, H.................................................... 100 Oliveros-Ramos, R...................................... 101 Oozeki, Y..................................................... 201 Orbi, A........................................... 76, 151, 185 Orensanz, L................................................. 101 Ortega, K..................................................... 165 Ortíz-Campos, E.......................................... 158 Ortlieb, L.................................... 59, 79, 82, 154 Oschlies, A.................................................. 117 Ostrowski, M...................................... 41, 49, 76 Osvaldo, U................................................... 149 Otero, J.................................................... 81, 95 Otero, P........................................ 107, 108, 159 Ouberdous, M.............................................. 125 Ould Bouzouma, M................................ 51, 103
Q
Quintero, M.E.............................................. 214 Quipúzcoa, L............................................... 148 Quispe, J..................................................... 138
R
Raimund, S.................................................. 121 Ramdani, M................................................... 46 Ramil, F........................................................ 169 Ramirez, N................................................... 211 Ramos, A................................. 51, 68, 104, 169 Ramos, F..................................................... 204 Ramos, V....................................................... 87 Ramzi, A...................................................... 185 Redondo-Rodriguez, A.................................. 56 Reguera, B.................................................. 159 Relvas, P.............................................. 136, 139 Renault, L............................................. 110, 116 Revilla, R..................................................... 181 Reyes, H................................................ 67, 211 Ribas-Ribas, M............................................ 153 Ribeiro, S....................................................... 70 Richardson, K.............................................. 109 Richardson, R.............................................. 172 Rienecker, E................................................ 132 Riquelme, K................................................. 207 Riveiro, I........................................................ 53 Rizzo-Aparicio, P........................................... 88 Roberts, D..................................................... 71 Roberts, R................................................... 231 Robinson, P................................................. 220 Rodrigues, T.................................................. 86 Rodríguez, C............................................... 127 Rodríguez, G............................................... 122 Rodríguez, J.M...................................... 69, 128 Rodríguez, N............................................... 233 Rodríguez-Sánchez, R................................ 200 Rodríguez-Santana, A................................. 120 Rodríguez-Ucha, I......................................... 88 Rojas de Mendiola, B.................................. 198 Romera Castillo, C...................................... 166 Romero, C..................................................... 51 Ronzon-Rodriguez, R.................................. 221 Rosa, R....................................................... 197 Rose, K........................................................ 227 Rosón, G............................................... 58, 165 Rossi, V......................................... 43, 123, 139 Roth, J........................................................... 92
P
Packard, T............................ 146, 152, 186, 233 Paduan, J.................................................... 162 Palma, S...................................................... 160 Paolini, P...................................................... 123 Parada, C............................................ 228, 230 Parés-Sierra, A...................................... 54, 117 Parma, A...................................................... 101 Parrilla, G.................................................... 120 Parrish, J..................................................... 215 Pastor, J...................................................... 182 Patti, B........................................................... 53 Paulmier, A.................................................. 153 Peard, K.......................................... 57, 60, 142 Pedraza, M.................................................. 104 Pelegri, J..................................................... 109 Peliz, A.................................................. 71, 128 Peña, A........................................................ 230 Peña, C....................................................... 213 Penven, P................ 47, 70, 131, 133, 135, 228 Peraltilla, S.......................................... 179, 201 Pereira, J..................................................... 137 Pérez, C...................................................... 183 Pérez, D........................................................ 89 Pérez, J....................................................... 204 Pérez-Marrero, J........................................... 87 Pesant, S..................................................... 176 Peteiro, L..................................................... 165 Peter, A-C.................................................... 121 Peterson, W................... 58, 131, 172, 192, 193 Petitgas, P.................................................... 204 Pfaff, M........................................ 135, 160, 161 Piedracoba, S................................ 58, 165, 194 Pierce, S...................................................... 131
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Eastern Boundary Upwelling Ecosystems Symposium Roux, J-P......................... 57, 60, 196, 203, 218 Roy, C.................................... 75, 124, 133, 227 Rubio, A....................................................... 130 Rueda Roa, D................................................ 88 Ruiz-Pion, D................................................ 153 Ruiz Villarreal, M................. 107, 108, 127, 159 Rutlant, J..................................................... 123 Ryan, J........................................ 132, 159, 175 Ryan, P........................................................ 217 Rykaczewski, R............................................. 93
Sobarzo, M.................................................. 189 Sobrinho-Gonçalves, L................................ 193 Solari, A............................................... 103, 105 Sørensen, L......................................... 109, 118 Soto, E......................................................... 169 Soto-Mardones, L.......................................... 54 Soto, S................................................. 169, 230 Soulat, F...................................................... 113 Soumah, M.................................................... 99 Souza, A.............................................. 158, 164 Sow, B......................................................... 124 Speich, S............................................. 130, 133 Spyrakos, E................................................... 89 Staby, A....................................................... 199 Steinhoff, T.................................................... 111 Steinke, M................................................... 185 Stenevik, E.................................................. 210 Stenseth, N.C........................................ 95, 225 Stramzka, M................................................ 125 Stratoudakis, Y..................................... 163, 204 Strub, P.T....................................................... 55 Suarez, D.................................................... 122 Sudre, J......................................................... 43 Sumaila, U..................................................... 99 Sundby, S.................................................... 210 Swartzman, G...................................... 174, 215 Sydeman, W.................................................. 92
S
Sabarros, P.................................................. 225 Sackmann, B............................................... 132 Saenz, B........................................................ 92 Salazar, C.................................................... 100 Salcido-Guevara, L...................................... 221 Salgueiro, E............................................. 73, 89 Salmerón, F................................................. 169 Salvanes, A.G.V........................................... 142 Salvatteci, R.................................................. 59 Sanchez-Arcilla, A......................................... 97 Sánchez, O.................................................. 167 Sánchez, R.................................. 107, 127, 139 Sanchez, S.................................................. 173 Sangrà, P............................. 108, 125, 126, 205 Sansó, B........................................................ 85 Santamaría-del-Angel, E............................. 158 Santamaría, M..................................... 213, 214 Santana-Casiano, J............................... 88, 124 Santos, A....................................................... 40 Santos, B..................................................... 204 Santos, M.................................................... 204 Santos Molina, J.......................................... 212 Sañudo Wilhelmy, S.A................................. 154 Sánz, J.L..................................................... 169 Schäfer-Neth, C........................................... 229 Schlitzer, R.......................................... 129, 229 Schmoker, C................................................ 192 Schneider, W....................................... 114, 120 Schwamborn, R................................... 173, 174 Segovia Zavala, J.A.................................... 154 Sepúlveda, A............................................... 129 Serra, N......................................................... 61 Serrano, W.................................................. 148 Serra, R....................................................... 208 Sessions, H......................................... 171, 190 Shaffer, S..................................................... 220 Shannon, L.... 41, 46, 47, 52, 91, 171, 196, 232 Shaw, C....................................................... 193 Shchepetkin, A............................................ 108 Sheridan, M................................................. 164 Shido, F....................................................... 227 Shillington, F............................ 49, 70, 131, 135 Shin, Y-J.......................................... 46, 91, 229 Sidibe, A........................................................ 99 Sidi Cheikh, M............................................. 211 Sielfeld, W..................................................... 72 Sifeddine, A............................... 59, 79, 82, 154 Silva, A................................................ 163, 204 Silva, S........................................................ 226 Simmons, S................................................. 220 Snaiki, Y....................................................... 209
T
Takasuka, A................................................. 201 Tam, J.............................. 46, 47, 101, 120, 194 Tapia, P.................................................. 59, 154 Tapia, R....................................................... 157 Tarazona, J.................................................. 165 Tassel, J...................................................... 139 Taylor, B......................................................... 81 Taylor, M...................................................... 194 Teixeira, I............................................. 184, 194 Teles-Machado, A.......................................... 71 Tello, O........................................................ 169 Tenorio, J..................................................... 138 Thiaw, M................................................ 72, 105 Thiom-Thiaw, O............................................. 72 Thomas, A............................................... 74, 86 Thual, S......................................................... 64 Tjizoo, B...................................................... 214 Torreblanca, L.............................................. 129 Torres Almarza, R........................................ 164 Torres, C...................................... 125, 138, 187 Torres Palenzuela, J.............................. 89, 140 Torres, R...................................................... 187 Torres, S...................................................... 146 Tovar Sánchez, A........................................ 154 Trainer, V..................................................... 159 Trasviña, A............................................. 54, 164 Travers, M..................................................... 91 Trees, C....................................................... 125 Tremblay, T.................................................. 220 Troupin, C............................................ 125, 126 Trudel, M....................................................... 60
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U
X
Uatjavi, U....................................................... 98 Ucha, I......................................................... 124 Ulloa, O....................................................... 178 Uriarte, A..................................................... 204 Utne Palm, A.C...................................... 96, 142
Xu, S............................................................ 182
Y
Yamanaka, Y................................................ 227 Yamashiro, C............................................... 194 Yáñez, E.............................................. 226, 233 Yang, J........................................................... 85 Yannicelli, B................................................. 101 Yataco, G..................................................... 219 Young, J....................................................... 185 Yupanqui, W................................................ 148 Yuras, G................................................ 90, 129
V
Valdés, J........................................................ 79 Valenzuela, C.............................................. 189 Valenzuela, V............................................... 211 Valle-Levinson, A......................................... 164 Valverde, M.................................................. 224 van der Lingen, C.. 41, 171, 183, 196, 197, 198, 200, 201, 230 van der Plas, A...................................... 41, 141 van Oordt, F................................................. 225 Vaqué, D...................................................... 167 Varas, A....................................................... 178 Varela, M............................................... 62, 108 Vargas, C..................................................... 189 Vargas, G....................................................... 59 Varo, N................................................. 163, 223 Vásquez, L........................... 116, 117, 138, 215 Vazquez, J..................................................... 77 Vega, J.L..................................................... 122 Vega, R........................................................ 226 Veitch, J......................................... 70, 131, 133 Velazco, F.................................. 59, 79, 82, 154 Vélez-Belchí, P............................................ 120 Venegas, R.................................................... 55 Vergara, A.R.................................................. 53 Verheye, H................................... 172, 181, 188 Verley, P......................................... 47, 133, 228 Vernet, M..................................................... 121 Veronica, M................................................. 149 Vidal, E........................................................ 231 Vilas, J.C..................................................... 134 Vilas, L......................................................... 140 Villalobos, H................................................. 200 Villegas, M..................................................... 72 Vincent, E.................................................... 110 Voelker, A................................................ 73, 86
Z
Zetina-Rejón, M........................................... 221 Zizah, S....................................... 151, 172, 181 Znari, M....................................................... 232 Zwolinski, J.................................................. 204
W
Wainer, I...................................................... 115 Waite, A....................................................... 176 Waldron, H..................................................... 63 Wallace, D................................................... 106 Wang, L....................................................... 182 Washburn, L................................................ 164 Watermeyer, K....................................... 91, 232 Weeks, S.J.................................................... 56 Wefer. G...................................................... 129 Weimerskirch, H.......................................... 217 Weise, M...................................................... 220 Weismerskirch, H........................................ 224 Werner, F..................................................... 227 Wieters, E.............................................. 48, 161 Wolff, M............................................... 173, 194
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