Author: "Véronique Garçon" - Searchworks@Jio Institute Digital Library Search Results

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1. Emergent constraint on oxygenation of the upper South Eastern Pacific oxygen minimum zone in the twenty-first century

Author: Ivan Almendra, Boris Dewitte, Véronique Garçon, Praxedes Muñoz, Carolina Parada, Ivonne Montes, Olaf Duteil, Aurélien Paulmier, Oscar Pizarro, Marcel Ramos, Wolfgang Koeve, and Andreas Oschlies
Subjects: Geology, QE1-996.5, Environmental sciences, GE1-350
Abstract: Abstract As a consequence of on-going global warming, the ocean is losing oxygen, which has implications not only in terms of marine resources management and food supply but also in terms of the potentially important feedback on the global carbon cycle and climate. Of particular scrutiny are the extended zones of already low levels of oxygen called the oxygen minimum zones (OMZs) embedded in the subsurface waters of the productive Eastern Boundary Upwelling Systems (EBUS). These OMZs are currently diversely simulated by state-of-the-art Earth System Models (ESM) hampering a reliable projection of ocean deoxygenation on marine ecosystem services in these regions. Here we focus on the most emblematic EBUS OMZs of the planet, that of the South Eastern Pacific (SEP), which is under the direct influence of the El Niño Southern Oscillation (ENSO), the main climate mode on interannual timescales at global scale. We show that, despite the low consensus among ESM long-term projections of oxygen levels, the sensitivity of the depth of the upper margin (oxycline) of the SEP OMZ to El Niño events in an ensemble of ESMs can be used as a predictor of its long-term trend, which establishes an emergent constraint for the SEP OMZ. Because the oxycline along the coast of Peru and Chile deepens during El Niño events, the upper bound of the SEP OMZ is thus likely to deepen in the future climate, therefore oxygenating the SEP OMZ. This has implications not only for understanding the nitrogen and carbon cycles at global scale but also for designing adaptation strategies for regional upper-ocean ecosystem services.
Published: 2024
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2. An ocean front dataset for the Mediterranean sea and southwest Indian ocean

Author: Floriane Sudre, Ismael Hernández-Carrasco, Camille Mazoyer, Joel Sudre, Boris Dewitte, Véronique Garçon, and Vincent Rossi
Subjects: Science
Abstract: Abstract Fronts are ubiquitous discrete features of the global ocean often associated with enhanced vertical velocities, in turn boosting primary production. Fronts thus form dynamical and ephemeral ecosystems where numerous species meet across all trophic levels. Fronts are also targeted by fisheries. Capturing ocean fronts and studying their long-term variability in relation with climate change is thus key for marine resource management and spatial planning. The Mediterranean Sea and the Southwest Indian Ocean are natural laboratories to study front-marine life interactions due to their energetic flow at sub-to-mesoscales, high biodiversity (including endemic and endangered species) and numerous conservation initiatives. Based on remotely-sensed Sea Surface Temperature and Height, we compute thermal fronts (2003–2020) and attracting Lagrangian coherent structures (1994–2020), in both regions over several decades. We advocate for the combined use of both thermal fronts and attracting Lagrangian coherent structures to study front-marine life interactions. The resulting front dataset differs from other alternatives by its high spatio-temporal resolution, long time coverage, and relevant thresholds defined for ecological provinces.
Published: 2023
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3. On the interpretation of changes in the subtropical oxygen minimum zone volume off Chile during two La Niña events (2001 and 2007)

Author: Matías Pizarro-Koch, Oscar Pizarro, Boris Dewitte, Ivonne Montes, Aurélien Paulmier, Véronique Garçon, Hector Hito Sepulveda, Andrea Corredor-Acosta, Catalina Aguirre, and Marcel Ramos
Subjects: subtropical Eastern Pacific, oxygen minimum zone, ENSO (El Niño/Southern Oscillation), Peru-Chile undercurrent, mesoscale eddy flux, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Oxygen minimum zones (OMZs) are extended oceanic regions for which dissolved oxygen concentration is extremely low. They are suspected to be expanding in response to global warming. However, currently, the mechanisms by which OMZ varies in response to climate variability are still uncertain. Here, the variability of the subtropical OMZ off central Chile of a regional coupled physical–biogeochemical regional model simulation was analyzed for the period 2000–2008, noting that its fluctuations were significant despite the relatively weak amplitude of the El Niño/Southern Oscillation (ENSO). In particular, the interannual variability in the OMZ volume (OMZVOL, defined as the volume with dissolved oxygen concentration (DO) ≤ 45μM) was approximately 38% larger than that of the seasonal cycle, with maximum and minimum anomalies of OMZVOL taking place during two cold La Niña (LN) years (2001 and 2007). The model analyses further reveal that these anomalies resulted from a combined effect of changes in (1) the oxygen-poor waters poleward transport by the Peru–Chile undercurrent (PCUC), (2) the intensity of quasi-zonal jets influencing the transport of water to and from the OMZ, and (3) the zonal DO transport related to mesoscale eddy activity. Specifically, the interannual variability of the PCUC modulated primarily the DO contents of the OMZ core [(DO) ≤ 20μM] and secondarily the OMZVOL, while cross-shore DO transport by the zonal jets and the eddy fluxes played a major role in ventilating and shaping the offshore extent of the OMZ. When the OMZVOL was maximum (minimum), the PCUC transport was slightly increased (reduced), which was associated with a reduction (increase) in the ventilation of the OMZ through negative (positive) anomalies of zonal advection and DO eddy fluxes. Our results demonstrate that significant natural interannual variability in the subtropical OMZ off Chile originates from the interplay between oceanic equatorial teleconnection (PCUC transport) and local non-linear dynamics (the zonal jets and mesoscale eddies).
Published: 2023
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4. Evaluating future climate change exposure of marine habitat in the South East Pacific based on metabolic constraints

Author: Alexandra Parouffe, Véronique Garçon, Boris Dewitte, Aurélien Paulmier, Ivonne Montes, Carolina Parada, Ariadna Mecho, and David Veliz
Subjects: metabolic index, climate velocities, South East Pacific, oxygen minimum zone, deoxygenation, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: IntroductionOn-going climate change is now recognized to yield physiological stresses on marine species, with potentially detrimental effects on ecosystems. Here, we evaluate the prospect of using climate velocities (CV) of the metabolic index (Φ) for assessing changes in habitat in the South East Pacific.MethodsOur approach is based on a species with mean ecophysiotype (i.e. model species) and the use of a global Earth System Model simulation (CESM-LE) under RCP 8.5 scenario. The SEP is chosen as a case study as it hosts an Oxygen Minimum Zone and seamounts systems sustaining local communities through artisanal fisheries.Results and DiscussionOur results indicate that CVΦ pattern is mainly constrained by the oxygen distribution and that its sign is affected by contrasting oxygen trends (including a re-oxygenation in the upper OMZ) and warming. We further show that CVΦ is weakly dependent on physiological traits composing Φ, which conveys to this metrics some value for inferring the projected mean displacement and potential changes in viability of metabolic habitat in a region where physiological data are scarce. Based on sensitivity experiments to physiological traits and natural variability, we propose a general method for inferring broad areas of climate change exposure regardless of species-specific Φ. We show in particular that for the model used here, the upper OMZ region can be considered a “safe” area for the species with ecophysiotype close to that of 71 species used to derive the model species. Limitations of the approach and perspectives of this work are also discussed.
Published: 2023
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5. Spatial and seasonal variability of horizontal temperature fronts in the Mozambique Channel for both epipelagic and mesopelagic realms

Author: Floriane Sudre, Boris Dewitte, Camille Mazoyer, Véronique Garçon, Joel Sudre, Pierrick Penven, and Vincent Rossi
Subjects: fronts, temperature fronts, seasonal variability, mozambique channel, ROMS-CROCO, Belkin and O’Reilly algorithm, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: IntroductionOcean fronts are moving ephemeral biological hotspots forming at the interface of cooler and warmer waters. In the open ocean, this is where marine organisms, ranging from plankton to mesopelagic fish up to megafauna, gather and where most fishing activities concentrate. Fronts are critical ecosystems so that understanding their spatio-temporal variability is essential not only for conservation goals but also to ensure sustainable fisheries. The Mozambique Channel (MC) is an ideal laboratory to study ocean front variability due to its energetic flow at sub-to-mesoscales, its high biodiversity and the currently debated conservation initiatives. Meanwhile, fronts detection relying solely on remotely-sensed Sea Surface Temperature (SST) cannot access aspects of the subsurface frontal activity that may be relevant for understanding ecosystem dynamics.MethodIn this study, we used the Belkin and O’Reilly Algorithm on remotely-sensed SST and hindcasts of a high-resolution nested ocean model to investigate the spatial and seasonal variability of temperature fronts at different depths in the MC.ResultsWe find that the seasonally varying spatial patterns of frontal activity can be interpreted as resulting from main features of the mean circulation in the MC region. In particular, horizontally, temperature fronts are intense and frequent along continental shelves, in islands’ wakes, at the edge of eddies, and in the pathways of both North-East Madagascar Current (NEMC) and South-East Madagascar Current (SEMC). In austral summer, thermal fronts in the MC are mainly associated with the Angoche upwelling and seasonal variability of the Mozambique current. In austral winter, thermal fronts in the MC are more intense when the NEMC and the Seychelles-Chagos and South Madagascar upwelling cells intensify. Vertically, the intensity of temperature fronts peaks in the vicinity of the mean thermocline.DiscussionConsidering the marked seasonality of frontal activity evidenced here and the dynamical connections of the MC circulation with equatorial variability, our study calls for addressing longer timescales of variability to investigate how ocean ecosystem/front interactions will evolve with climate change.
Published: 2023
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6. A Global Ocean Oxygen Database and Atlas for Assessing and Predicting Deoxygenation and Ocean Health in the Open and Coastal Ocean

Author: Marilaure Grégoire, Véronique Garçon, Hernan Garcia, Denise Breitburg, Kirsten Isensee, Andreas Oschlies, Maciej Telszewski, Alexander Barth, Henry C. Bittig, Jacob Carstensen, Thierry Carval, Fei Chai, Francisco Chavez, Daniel Conley, Laurent Coppola, Sean Crowe, Kim Currie, Minhan Dai, Bruno Deflandre, Boris Dewitte, Robert Diaz, Emilio Garcia-Robledo, Denis Gilbert, Alessandra Giorgetti, Ronnie Glud, Dimitri Gutierrez, Shigeki Hosoda, Masao Ishii, Gil Jacinto, Chris Langdon, Siv K. Lauvset, Lisa A. Levin, Karin E. Limburg, Hela Mehrtens, Ivonne Montes, Wajih Naqvi, Aurélien Paulmier, Benjamin Pfeil, Grant Pitcher, Sylvie Pouliquen, Nancy Rabalais, Christophe Rabouille, Virginie Recape, Michaël Roman, Kenneth Rose, Daniel Rudnick, Jodie Rummer, Catherine Schmechtig, Sunke Schmidtko, Brad Seibel, Caroline Slomp, U. Rashid Sumalia, Toste Tanhua, Virginie Thierry, Hiroshi Uchida, Rik Wanninkhof, and Moriaki Yasuhara
Subjects: oxygen, atlas, database, observing, mapping, data-products, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO2DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO2DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO2DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO2DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O2 changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data synthesis products with unprecedented spatial (vertical and horizontal) and temporal (sub-seasonal to multi-decadal) resolution. These products will support model assessment, improvement and evaluation as well as the development of climate and ocean health indicators. They will further support the decision-making processes associated with the emerging blue economy, the conservation of marine resources and their associated ecosystem services and the development of management tools required by a diverse community of users (e.g., environmental agencies, aquaculture, and fishing sectors). A better knowledge base of the spatial and temporal variations of marine O2 will improve our understanding of the ocean O2 budget, and allow better quantification of the Earth’s carbon and heat budgets. With the ever-increasing need to protect and sustainably manage ocean services, GO2DAT will allow scientists to fully harness the increasing volumes of O2 data already delivered by the expanding global ocean observing system and enable smooth incorporation of much higher quantities of data from autonomous platforms in the open ocean and coastal areas into comprehensive data products in the years to come. This paper aims at engaging the community (e.g., scientists, data managers, policy makers, service users) toward the development of GO2DAT within the framework of the UN Global Ocean Oxygen Decade (GOOD) program recently endorsed by IOC-UNESCO. A roadmap toward GO2DAT is proposed highlighting the efforts needed (e.g., in terms of human resources).
Published: 2021
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7. High-Sustained Concentrations of Organisms at Very low Oxygen Concentration Indicated by Acoustic Profiles in the Oxygen Deficit Region Off Peru

Author: Aurelien Paulmier, Gerard Eldin, José Ochoa, Boris Dewitte, Joël Sudre, Véronique Garçon, Jaques Grelet, Kobi Mosquera-Vásquez, Oscar Vergara, and Helmut Maske
Subjects: microaerobic zooplankton, lowered ADCP, oxygen minimum zone (OMZ), biomass below OMZ, Eastern Tropical South Pacific, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: The oxygen deficient mesopelagic layer (ODL) off Peru has concentrations below 5 μmol O2 kg–1 and is delimited by a shallow upper oxycline with strong vertical gradient and a more gradual lower oxycline (lOx). Some regions show a narrow band of slightly increased oxygen concentrations within the ODL, an intermediate oxygen layer (iO2). CTD, oxygen and lowered Acoustic Doppler Current Profiler (LADCP, 300 kHz) profiles were taken on the shelf edge and outside down to mostly 2000 m. We evaluate here the acoustic volume backscatter strength of the LADCP signal representing organisms of about 5 mm size. Dominant features of the backscatter profiles were a minimum backscatter strength within the ODL, and just below the lOx a marked backscatter increase reaching a maximum at less than 3.0 μmol O2 kg–1. Below this maximum, the acoustic backscatter strength gradually decreased down to 1000 m below the lOx. The backscatter strength also increased at the iO2 in parallel to the oxygen concentration perturbations marking the iO2. These stable backscatter features were independent of the time of day and the organisms represented by the backscatter had to be adapted to live in this microaerobic environment. During daylight, these stable structures were overlapped by migrating backscatter peaks. Outstanding features of the stable backscatter were that at very low oxygen concentrations, the volume backscatter was linearly related to the oxygen concentration, reaching half peak maximum at less than 2.0 μmol O2 kg–1 below the lOx, and the depth-integrated backscatter of the peak below the lOx was higher than the integral above the Ox. Both features suggest that sufficient organic material produced at the surface reaches to below the ODL to sustain the major fraction of the volume backscatter-producing organisms in the water column. These organisms are adapted to the microaerobic environment so they can position themselves close to the lower oxycline to take advantage of the organic particles sinking out of the ODL.
Published: 2021
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8. Multidisciplinary Observing in the World Ocean’s Oxygen Minimum Zone Regions: From Climate to Fish — The VOICE Initiative

Author: Véronique Garçon, Johannes Karstensen, Artur Palacz, Maciej Telszewski, Tony Aparco Lara, Denise Breitburg, Francisco Chavez, Paulo Coelho, Marcela Cornejo-D’Ottone, Carmen Santos, Björn Fiedler, Natalya D. Gallo, Marilaure Grégoire, Dimitri Gutierrez, Martin Hernandez-Ayon, Kirsten Isensee, Tony Koslow, Lisa Levin, Francis Marsac, Helmut Maske, Baye C. Mbaye, Ivonne Montes, Wajih Naqvi, Jay Pearlman, Edwin Pinto, Grant Pitcher, Oscar Pizarro, Kenneth Rose, Damodar Shenoy, Anja Van der Plas, Melo R. Vito, and Kevin Weng
Subjects: oxygen minimum zones, oxycline, ocean observing system, multidisciplinary, readiness level, ecosystem, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Multidisciplinary ocean observing activities provide critical ocean information to satisfy ever-changing socioeconomic needs and require coordinated implementation. The upper oxycline (transition between high and low oxygen waters) is fundamentally important for the ecosystem structure and can be a useful proxy for multiple observing objectives connected to eastern boundary systems (EBSs) that neighbor oxygen minimum zones (OMZs). The variability of the oxycline and its impact on the ecosystem (VOICE) initiative demonstrates how societal benefits drive the need for integration and optimization of biological, biogeochemical, and physical components of regional ocean observing related to EBS. In liaison with the Global Ocean Oxygen Network, VOICE creates a roadmap toward observation-model syntheses for a comprehensive understanding of selected oxycline-dependent objectives. Local to global effects, such as habitat compression or deoxygenation trends, prompt for comprehensive observing of the oxycline on various space and time scales, and for an increased awareness of its impact on ecosystem services. Building on the Framework for Ocean Observing (FOO), we present a first readiness level assessment for ocean observing of the oxycline in EBS. This was to determine current ocean observing design and future needs in EBS regions (e.g., the California Current System, the Equatorial Eastern Pacific off Ecuador, the Peru–Chile Current system, the Northern Benguela off Namibia, etc.) building on the FOO strategy. We choose regional champions to assess the ocean observing design elements proposed in the FOO, namely, requirement processes, coordination of observational elements, and data management and information products and the related best practices. The readiness level for the FOO elements was derived for each EBS through a similar and very general ad hoc questionnaire. Despite some weaknesses in the questionnaire design and its completion, an assessment was achievable. We found that fisheries and ecosystem management are a societal requirement for all regions, but maturity levels of observational elements and data management and information products differ substantially. Identification of relevant stakeholders, developing strategies for readiness level improvements, and building and sustaining infrastructure capacity to implement these strategies are fundamental milestones for the VOICE initiative over the next 2–5 years and beyond.
Published: 2019
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9. First Deployment and Validation of in Situ Silicate Electrochemical Sensor in Seawater

Author: Carole Barus, Dancheng Chen Legrand, Nicolas Striebig, Benoit Jugeau, Arnaud David, Maria Valladares, Praxedes Munoz Parra, Marcel E. Ramos, Boris Dewitte, and Véronique Garçon
Subjects: autonomous sensor, reagentless electrochemical detection, silicate, seawater, mooring and float deployments, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: An electrochemical sensor is proposed to measure silicate concentration, in situ, in the ocean without any addition of liquid reagent. From the analytical principle to the laboratory prototype toward the first in situ, immersible sensor, the evolution of the mechanical design is presented and discussed. The developed in situ electronics were compared to the commercial potentiostat and gave promising results to detect low silicate signals with a limit of quantification of 1 μmol L−1.The flow rate of the pump appeared to be a crucial parameter in order to transfer the silicomolybdic complex formed from the “complexation cell” to the “detection cell” without dilution as well as to fill and rinse the whole circuit. The study of temperature effect revealed no influence on the electrochemical signal between ~7° and ~21°C. Finally the sensor was successfully deployed for the very first time on a mooring off Coquimbo, Chile and also integrated onto a PROVOR profiling float in the Mediterranean Sea off Villefranche-sur-Mer, France. The data collected and/or sent through satellite were in good agreement with the 2 reference samples and previously published values illustrating the great potential of this electrochemical sensor. A 7 days silicate time series from the mooring deployment off Chile is also presented.
Published: 2018
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10. Physical and Biological Satellite Observations of the Northwest African Upwelling: Spatial Extent and Dynamics.

Author: Anass El Aouni, Véronique Garçon, Joël Sudre, Hussein M. Yahia, Khalid Daoudi, and Khalid Minaoui
Published: 2020
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11. Increasing the Resolution of Ocean pCO2 Maps in the South Eastern Atlantic Ocean Merging Multifractal Satellite-Derived Ocean Variables.

Author: Ismael Hernandez-Carrasco, Véronique Garçon, Joël Sudre, Christoph S. Garbe, and Hussein M. Yahia
Published: 2018
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12. Effect of wind stress forcing on ocean dynamics at air-sea interface.

Author: Hussein M. Yahia, Véronique Garçon, Joël Sudre, and Christophe Maes
Published: 2018
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13. Ocean Turbulent Dynamics at Superresolution From Optimal Multiresolution Analysis and Multiplicative Cascade.

Author: Joël Sudre, Hussein M. Yahia, Oriol Pont, and Véronique Garçon
Published: 2015
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14. Climatically-active gases in the Eastern Boundary Upwelling and Oxygen Minimum Zone (OMZ) systems.

Author: Christoph S. Garbe, André Butz, Isabelle Dadou, Boris Dewitte, Véronique Garçon, Serena Illig, Aurélien Paulmier, Joël Sudre, and Hussein M. Yahia
Published: 2012
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15. Motion analysis in oceanographic satellite images using multiscale methods and the energy cascade.

Author: Hussein M. Yahia, Joël Sudre, Claire Pottier, and Véronique Garçon
Published: 2010
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16. Merging SeaWiFS and MODIS/Aqua Ocean Color Data in North and Equatorial Atlantic Using Weighted Averaging and Objective Analysis.

Author: Claire Pottier, Véronique Garçon, Gilles Larnicol, Joël Sudre, Philippe Schaeffer, and Pierre-Yves Le Traon
Published: 2006
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17. High-Sustained Concentrations of Organisms at Very low Oxygen Concentration Indicated by Acoustic Profiles in the Oxygen Deficit Region Off Peru

Author: Carlos Conejero, Javier Sellanes, Carlos Gaymer, Marilaure Grégoire, Daniel J. Conley, Ariadna Mechó, Ivonne Montes, Lisa A. Levin, Anja van der Plas, Anja Engel, Aurélien Paulmier, Renato Salvatteci, Alberto Lorenzo, Dimitri Gutiérrez, Gérard Eldin, Carolina Parada, Naqvi Swa, Jacob Carstensen, Dante Espinoza-Morriberón, Jaques Grelet, Anne Gro Vea Salvanes, Boris Dewitte, Jing Zhang, Denise L. Breitburg, Abdelfettah Sifeddine, J. Sudre, Michael R. Roman, José Martín Hernández-Ayón, Kobi Mosquera-Vásquez, Georgina Flores, Lander Merma, José Ochoa, Véronique Garçon, Zy Zhu, Helmut Maske, Michelle Graco, Luis Bravo, Arturo Aguirre-Velarde, Jorge Cardich, Grant C. Pitcher, Eric Machu, Oscar Vergara, Moriaki Yasuhara, Huai-Hsuan May Huang, María Elena Jacinto, Sonia Sánchez, Abdoul Wahab Tall, Raleigh R. Hood, Praxedes Muñoz, Nancy N. Rabalais, Kenneth A. Rose, Kirsten Isensee, Marcel Ramos, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Departamento de Oceanografia Fisica CICESE [Mexico], Centro de Investigacion Cientifica y de Education Superior de Ensenada [Mexico] (CICESE), Departamento de Biología Marina [Coquimbo], Universidad Católica del Norte [Antofagasta], Centro de Estudios Avanzados en Zonas Aridas (CEAZA), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), Instrumentation, Moyens analytiques, Observatoires en Géophysique et Océanographie (IMAGO), Instituto Geofísico del Perú (IGP), Collecte Localisation Satellites (CLS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Investigacion Científica y de Educacion Superior de Ensenada, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
Subjects: 010504 meteorology & atmospheric sciences, Backscatter, Eastern Tropical South Pacific, Mesopelagic zone, Science, [SDE.MCG]Environmental Sciences/Global Changes, Analytical chemistry, chemistry.chemical_element, Ocean Engineering, Aquatic Science, QH1-199.5, Oceanography, 01 natural sciences, Oxygen, 03 medical and health sciences, Water column, Acoustic Doppler current profiler, oxygen minimum zone (OMZ), [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 030304 developmental biology, 0105 earth and related environmental sciences, Water Science and Technology, 0303 health sciences, Global and Planetary Change, microaerobic zooplankton, Low oxygen, Chemistry, General. Including nature conservation, geographical distribution, biomass below OMZ, 15. Life on land, lowered ADCP, Volume (thermodynamics), Limiting oxygen concentration
Abstract: The oxygen deficient mesopelagic layer (ODL) off Peru has concentrations below 5 μmol O2 kg–1 and is delimited by a shallow upper oxycline with strong vertical gradient and a more gradual lower oxycline (lOx). Some regions show a narrow band of slightly increased oxygen concentrations within the ODL, an intermediate oxygen layer (iO2). CTD, oxygen and lowered Acoustic Doppler Current Profiler (LADCP, 300 kHz) profiles were taken on the shelf edge and outside down to mostly 2000 m. We evaluate here the acoustic volume backscatter strength of the LADCP signal representing organisms of about 5 mm size. Dominant features of the backscatter profiles were a minimum backscatter strength within the ODL, and just below the lOx a marked backscatter increase reaching a maximum at less than 3.0 μmol O2 kg–1. Below this maximum, the acoustic backscatter strength gradually decreased down to 1000 m below the lOx. The backscatter strength also increased at the iO2 in parallel to the oxygen concentration perturbations marking the iO2. These stable backscatter features were independent of the time of day and the organisms represented by the backscatter had to be adapted to live in this microaerobic environment. During daylight, these stable structures were overlapped by migrating backscatter peaks. Outstanding features of the stable backscatter were that at very low oxygen concentrations, the volume backscatter was linearly related to the oxygen concentration, reaching half peak maximum at less than 2.0 μmol O2 kg–1 below the lOx, and the depth-integrated backscatter of the peak below the lOx was higher than the integral above the Ox. Both features suggest that sufficient organic material produced at the surface reaches to below the ODL to sustain the major fraction of the volume backscatter-producing organisms in the water column. These organisms are adapted to the microaerobic environment so they can position themselves close to the lower oxycline to take advantage of the organic particles sinking out of the ODL.
Published: 2021

18. System controls of coastal and open ocean oxygen depletion

Author: Dimitri Gutiérrez, Véronique Garçon, Naqvi Swa, Lander Merma, Abdelfettah Sifeddine, Boris Dewitte, Alberto Lorenzo, Lisa A. Levin, Anja Engel, Aurélien Paulmier, Marilaure Grégoire, Renato Salvatteci, Sonia Sánchez, María E. Jacinto, Kenneth A. Rose, Georgina Flores, Daniel J. Conley, Ivonne Montes, Anja van der Plas, Zhuoyi Zhu, Arturo Aguirre-Velarde, Dante Espinoza-Morriberón, José Martín Hernández-Ayón, Denise L. Breitburg, Kirsten Isensee, Michael R. Roman, Nancy N. Rabalais, Abdoul Wahab Tall, Michelle Graco, Huai Hsuan May Huang, Jorge Cardich, Grant C. Pitcher, Eric Machu, Raleigh R. Hood, Anne Gro V. Salvanes, Jing Zhang, Moriaki Yasuhara, Jacob Carstensen, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Fisheries Research and Development, Department of Forestry, Fisheries and the Environment, Department of Biological Sciences [Cape Town], University of Cape Town, Instituto del Mar del Peru (IMARPE), Smithsonian Environmental Research Center, Smithsonian Institution, Universidad Peruana Cayetana Heredia - UPCH (PERU), Aarhus University [Aarhus], Department of Geology [Lund], Lund University [Lund], Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Department of Astrophysics, Geophysics and Oceanography, Université de Liège, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Environment and Life Sciences Research Center, Variabilité à long terme du climat de l'océan (VALCO), Laboratoire de Physique de l'Atmosphère et de l'Océan Siméon Fongang (LPAO-SF), École Supérieure Polytechnique de Dakar (ESP), Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD)-Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), School of biological sciences (Hong Kong, Chine), The University of Hong Kong (HKU), State Key Laboratory of Estuarine and Coastal Research, Universidad Peruana Cayetano Heredia (UPCH), Institut de Recherche pour le Développement (IRD), Centro de Estudios Avanzados en Zonas Aridas (CEAZA), Université de Liège - Faculté des sciences appliquées (ULIEGE FSA), Universidad Autónoma de Baja California (UABC), City University of Hong Kong [Hong Kong] (CUHK), United Nations Educational, Scientific and Cultural Organization (UNESCO), Department of Earth Sciences [University of Southern California], University of Southern California (USC), Instituto Geofísico del Perú (IGP), Environment and Life Sciences Research Center koweit, Hitachi Cambridge Laboratory [University of Cambridge], University of Cambridge [UK] (CAM)-Hitachi, Ltd, Department of Electrical and Computer Engineering [Univ. of Maryland] (ECE - University of Maryland), Louisiana State University (LSU), University of Bergen (UiB), Kiel University, Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), East China Normal University [Shangaï] (ECNU), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, chemistry.chemical_element, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Aquatic Science, PACIFIQUE, PEROU, 01 natural sciences, Oxygen, EQUATEUR, Anthropocene, OCEAN INDIEN, CHILI, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Continental shelf, 010604 marine biology & hydrobiology, Global warming, Respiration, NORVEGE, Geology, Pelagic zone, Deoxygenation, 15. Life on land, Eutrophication, Ventilation, ATLANTIQUE, Oceanography, Stratification (seeds), chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Environmental science, Stratification, Hydrography
Abstract: Highlights: • The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygen-depleted environments in both coastal and open ocean systems since the middle of the 20th century. • This review paper provides a synthesis of system-specific drivers of low oxygen in a range of case studies representing marine systems in the open ocean, on continental shelves, in enclosed seas and in the coastal environment. • Identification of similar and contrasting responses within and across system types and corresponding oxygen regimes is shown to be informative both in understanding and isolating key controlling processes and provides a sound basis for predicting change under anticipated future conditions. • Case studies were selected to achieve a balance in system diversity and global coverage. • Each case study describes system attributes, including the present-day oxygen environment and known trends in oxygen concentrations over time. • Central to each case study is the identification of the physical and biogeochemical processes that determine oxygen concentrations through the tradeoff between ventilation and respiration. • Spatial distributions of oxygen and time series of oxygen data provide the opportunity to identify trends in oxygen availability and have allowed various drivers of low oxygen to be distinguished through correlative and causative relationships. • Deoxygenation results from a complex interplay of hydrographic and biogeochemical processes and the superposition of these processes, some additive and others subtractive, makes attribution to any particular driver challenging. • System-specific models are therefore required to achieve a quantitative understanding of these processes and of the feedbacks between processes at varying scales. Abstract: The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygen-depleted environments in both coastal and open ocean systems since the middle of the 20th century. This paper provides a review of system-specific drivers of low oxygen in a range of case studies representing marine systems in the open ocean, on continental shelves, in enclosed seas and in the coastal environment. Identification of similar and contrasting responses within and across system types and corresponding oxygen regimes is shown to be informative both in understanding and isolating key controlling processes and provides a sound basis for predicting change under anticipated future conditions. Case studies were selected to achieve a balance in system diversity and global coverage. Each case study describes system attributes, including the present-day oxygen environment and known trends in oxygen concentrations over time. Central to each case study is the identification of the physical and biogeochemical processes that determine oxygen concentrations through the tradeoff between ventilation and respiration. Spatial distributions of oxygen and time series of oxygen data provide the opportunity to identify trends in oxygen availability and have allowed various drivers of low oxygen to be distinguished through correlative and causative relationships. Deoxygenation results from a complex interplay of hydrographic and biogeochemical processes and the superposition of these processes, some additive and others subtractive, makes attribution to any particular driver challenging. System-specific models are therefore required to achieve a quantitative understanding of these processes and of the feedbacks between processes at varying scales.
Published: 2021

19. Increasing the Resolution of Ocean pCO2 Maps in the South Eastern Atlantic Ocean Merging Multifractal Satellite-Derived Ocean Variables

Author: Joël Sudre, Ismael Hernández-Carrasco, Christoph S. Garbe, Véronique Garçon, and Hussein Yahia
Subjects: 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Boundary (topology), 02 engineering and technology, Multifractal system, Regional Ocean Modeling System, 01 natural sciences, Sea surface temperature, Fractal, 13. Climate action, Climatology, General Earth and Planetary Sciences, Upwelling, Satellite, 14. Life underwater, Electrical and Electronic Engineering, Image resolution, Geology, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences
Abstract: A new methodology has been developed in order to improve the description of the spatial and temporal variability of not well-resolved oceanic variables from other well-observed high-resolution oceanic variables. The method is based on the cross-scale inference of information, incorporating the common features of different multifractal high-resolution variables into a coarser one. An exercise of validation of the methodology has been performed based on the outputs of coupled physical-biogeochemical Regional Ocean Modeling System adapted to the eastern boundary upwelling systems at two spatial resolutions. Once the algorithm has been proved to be effective in increasing the spatial resolution of modeled partial pressure of CO2 at the surface ocean (pCO2), we have investigated the capability of our methodology when it is applied to remote sensing data, focusing on the improvement of the temporal description. In this regard, we have inferred daily pCO2 maps at high resolution (4 km, i.e., 1/24°) fusing monthly pCO2 data at low resolution (100 km, i.e., 1°) with the small-scale features contained in daily high-resolution maps of satellite sea surface temperature and Chlorophyll-a. The algorithm has been applied to the South Eastern Atlantic Ocean opening the possibility to obtain an accurate quantification of the CO2 fluxes in relevant coastal regions, such as the eastern boundary upwelling systems. Outputs of our algorithm have been compared with in situ measurements, showing that daily maps inferred from monthly products are in average 6 $\mu $ atm closer to the in situ values than the original coarser monthly maps. Furthermore, values of pCO2 have been improved in points close to the coast with respect to the original input data.
Published: 2018

20. WTO must ban harmful fisheries subsidies

Author: Gert van Santen, John M. Anderies, Donovan Campbell, Tyler D. Eddy, Omu Kakujaha-Matundu, Bryce D. Stewart, Marten Scheffer, Jessica Fanzo, Rowenna Gryba, F. Stuart Chapin, Denis Worlanyo Aheto, Katina Roumbedakis, Ibrahim Issifu, Gordon R. Munro, Shakuntala H. Thilsted, Ibukun Jacob Adewumi, Evgeny A. Pakhomov, Grant Murray, Jason F. Shogren, Unai Pascual, Satoshi Yamazaki, Margaret Spring, Carlos M. Duarte, Kathleen Segerson, U. Rashid Sumaila, Precious Agbeko Dzorgbe Mattah, Kyle Gillespie, Saleem Mustafa, Lan Xiao, Joshua Adotey, Frances Westley, Francis K. E. Nunoo, Frank Asche, Zuzy Anna, Boris Worm, D. R. Fraser Taylor, Diva J. Amon, Roshni S. Mangar, Cassandra M. Brooks, Frederik Noack, Brooks Kaiser, Nathan J. Bennett, William W. L. Cheung, Dwight Owens, S. Kim Juniper, Derek Armitage, Karly McMullen, Dawn Kotowicz, Enric Sala, Paul O. Onyango, Francis E. Asuquo, Kristin M. Kleisner, Monirul Islam, Juliano Palacios Abrantes, Tony Charles, Dana D. Miller, Sarah Harper, Louise S. L. Teh, Juan José Alava, Aurélien Paulmier, Jeremy B. C. Jackson, Santiago de la Puente, Colin W. Clark, Jennifer J. Silver, Robert Blasiak, Colette C. C. Wabnitz, Gretchen C. Daily, Lydia C. L. Teh, John A. List, Alessandro Tavoni, Philippe D. Tortell, Tabitha Mallory, Jaime Mendo, Amadou Tall, Essam Yassin Mohammed, Romola V. Thumbadoo, Kristen Hopewell, Rebecca R. Helm, Mauricio Castrejón, Elena M. Bennett, Jean-Baptiste Thiebot, Jorge Jimenez Ramon, Patrick Kimani, Gerald G. Singh, Kátia Meirelles Felizola Freire, Johannes A. Iitembu, Sara E. Cannon, Jorge Ramírez, Richard S.J. Tol, Evelyn Pinkerton, Andrew Forrest, Juan Camilo Cárdenas Campo, Sadique Isahaku, Dyhia Belhabib, Moenieba Isaacs, Laura G. Elsler, Alessandro Tagliabue, Tom Okey, Tessa Owens, Alex J. Caveen, José-María Da-Rocha, Isigi Kadagi, Hong Yang, Ekow Prah, Glenn-Marie Lange, Mary S. Wisz, Vicky W. L. Lam, Maartje Oostdijk, Daniel Pauly, Torsten Thiele, Michel J. Kaiser, Christina C. Hicks, Nancy C. Doubleday, Nicholas K. Dulvy, Line Gordon, Thomas L. Frölicher, Kwasi Appeaning Addo, Katherine Millage, Alfredo Giron-Nava, Heike K. Lotze, Lincoln Hood, Michelle Tigchelaar, Keita Abe, S. Karuaihe, Nancy Knowlton, Jessica A. Gephart, Noble K. Asare, Werner Antweiler, Christopher D. G. Harley, Kai M. A. Chan, Rodrigue Orobiyi Edéya Pèlèbè, Duncan Burnside, Sarah Glaser, Hussain Sinan, Garry D. Peterson, Olaf P. Jensen, Don Robadue, Mafaniso Hara, Sahir Advani, Andreea L. Cojocaru, Fiorenza Micheli, Gakushi Ishimura, Berchie Asiedu, Tu Nguyen, Mohammed Oyinlola, Lubna Alam, Maria A. Gasalla, Priscila F. M. Lopes, Mary Karumba, Austin J. Gallagher, Sufian Jusoh, Brian R. Copeland, Christopher M. Anderson, Alberta Jonah, Christopher D. Golden, Fabrice Stephenson, Douglas J. McCauley, Isaac Okyere, Jennifer Jacquet, Elke U. Weber, Benjamin S. Halpern, Olanike Kudirat Adeyemo, Neil Adger, Nina Wambiji, Kristina M. Gjerde, A. Eyiwunmi Falaye, Polina Orlov, Umi Muawanah, Trevor Church, Denise Breitburg, J. P. Walsh, Edward H. Allison, Cullen S. Hendrix, Curtis A. Suttle, Thuy Thi Thanh Pham, Cesar Bordehore, Michael Harte, Xavier Basurto, Carol McAusland, Rainer Froese, Adibi R. M. Nor, Anne-Sophie Crépin, Karen C. Seto, Abhipsita Das, Philippe Cury, Masahide Kaeriyama, Peter Freeman, Dacotah-Victoria Splichalova, Nobuyuki Yagi, Natalie C. Ban, Larry B. Crowder, Véronique Garçon, Amanda T. Lombard, Katie R. N. Florko, Nicolás Talloni-Álvarez, Riad Sultan, Lisa A. Levin, Mimi E. Lam, Evans K. Arizi, Richard T. Carson, Megan Bailey, Steven J. Lade, Zahidah Afrin, Dianne Newell, Shanta C. Barley, Colin Barnes, Villy Christensen, Dirk Zeller, Simon A. Levin, Kolliyil Sunil Mohamed, Marta Flotats Aviles, Jonathan D. R. Houghton, Daniel J. Skerritt, Karin E. Limburg, Meaghan Efford, Michael C. Melnychuk, Lanre Badmus, Sebastián Villasante, Carie Hoover, Evan Andrews, Daniel Peñalosa, Allison N. Cutting, Nathan Pacoureau, Melissa Walsh, Wisdom Akpalu, Kafayat Adetoun Fakoya, Ling Cao, Edward B. Barbier, Clare Fitzsimmons, Alex Rogers, Robert Arthur, Daniel Marszalec, Jean-Baptiste Jouffray, Carl Folke, Anna Schuhbauer, Mazlin Mokhtar, Juan Mayorga, Ingrid van Putten, S.L. Akintola, Stephen Polasky, Lance Morgan, Jesper Stage, Lucas Brotz, M. Selçuk Uzmanoğlu, Boris Dewitte, Ahmed Khan, Ernest Obeng Chuku, Veronica Relano, Nicholas Polunin, Griffin Carpenter, Virginie Bornarel, Max Troell, Bárbara Horta e Costa, Lian E. Kwong, Mairin C. M. Deith, Valérie Le Brenne, Dan Laffoley, Hugh Govan, Ronaldo Angelini, Juan Carlos Villaseñor-Derbez, Mark J. Gibbons, Ambre Soszynski, Ola Flaaten, Stella Williams, M. Nicole Chabi, S. R. Carpenter, Prateep Kumar Nayak, David Obura, Scott Barrett, Philippe Le Billon, Patrízia Raggi Abdallah, John J. Bohorquez, Adriana Rosa Carvalho, Andrés M. Cisneros-Montemayor, Paul R. Ehrlich, John Kurien, Juan Carlos Seijo, Dominique Benzaken, Brian Crawford, Callum M. Roberts, Gabriel Reygondeau, Xue Jin, Julia Adelsheim, Mohd Talib Latif, Annie Mejaes, Frank Meere, Jeffrey McLean, Jennifer Dianto Kemmerly, Henrik Österblom, Savior K. S. Deikumah, Tayler M. Clarke, Aart de Zeeuw, Frédéric Le Manach, Maria Grazia Pennino, Quentin A Hanich, David R. Boyd, Sumaila, U Rashid, Skerritt, Daniel J, Schuhbauer, Anna, Villasante, Sebastian, Cisneros-Montemayor, Andrés M, Sinan, Hussain, Burnside, Duncan, Abdallah, Patrízia Raggi, Abe, Keita, Addo, Kwasi A, Adelsheim, Julia, Adewumi, Ibukun J, Adeyemo, Olanike K, Adger, Neil, Adotey, Joshua, Advani, Sahir, Afrin, Zahidah, Aheto, Deni, Akintola, Shehu L, Akpalu, Wisdom, Alam, Lubna, Alava, Juan José, Allison, Edward H, Amon, Diva J, Anderies, John M, Anderson, Christopher M, Andrews, Evan, Angelini, Ronaldo, Anna, Zuzy, Antweiler, Werner, Arizi, Evans K, Armitage, Derek, Arthur, Robert I, Asare, Noble, Asche, Frank, Asiedu, Berchie, Asuquo, Franci, Badmus, Lanre, Bailey, Megan, Ban, Natalie, Barbier, Edward B, Barley, Shanta, Barnes, Colin, Barrett, Scott, Basurto, Xavier, Belhabib, Dyhia, Bennett, Elena, Bennett, Nathan J, Benzaken, Dominique, Blasiak, Robert, Bohorquez, John J, Bordehore, Cesar, Bornarel, Virginie, Boyd, David R, Breitburg, Denise, Brooks, Cassandra, Brotz, Luca, Campbell, Donovan, Cannon, Sara, Cao, Ling, Cardenas Campo, Juan C, Carpenter, Steve, Carpenter, Griffin, Carson, Richard T, Carvalho, Adriana R, Castrejón, Mauricio, Caveen, Alex J, Chabi, M Nicole, Chan, Kai M A, Chapin, F Stuart, Charles, Tony, Cheung, William, Christensen, Villy, Chuku, Ernest O, Church, Trevor, Clark, Colin, Clarke, Tayler M, Cojocaru, Andreea L, Copeland, Brian, Crawford, Brian, Crépin, Anne-Sophie, Crowder, Larry B, Cury, Philippe, Cutting, Allison N, Daily, Gretchen C, Da-Rocha, Jose Maria, Das, Abhipsita, de la Puente, Santiago, de Zeeuw, Aart, Deikumah, Savior K S, Deith, Mairin, Dewitte, Bori, Doubleday, Nancy, Duarte, Carlos M, Dulvy, Nicholas K, Eddy, Tyler, Efford, Meaghan, Ehrlich, Paul R, Elsler, Laura G, Fakoya, Kafayat A, Falaye, A Eyiwunmi, Fanzo, Jessica, Fitzsimmons, Clare, Flaaten, Ola, Florko, Katie R N, Aviles, Marta Flotat, Folke, Carl, Forrest, Andrew, Freeman, Peter, Freire, Kátia M F, Froese, Rainer, Frölicher, Thomas L, Gallagher, Austin, Garcon, Veronique, Gasalla, Maria A, Gephart, Jessica A, Gibbons, Mark, Gillespie, Kyle, Giron-Nava, Alfredo, Gjerde, Kristina, Glaser, Sarah, Golden, Christopher, Gordon, Line, Govan, Hugh, Gryba, Rowenna, Halpern, Benjamin S, Hanich, Quentin, Hara, Mafaniso, Harley, Christopher D G, Harper, Sarah, Harte, Michael, Helm, Rebecca, Hendrix, Cullen, Hicks, Christina C, Hood, Lincoln, Hoover, Carie, Hopewell, Kristen, Horta E Costa, Bárbara B, Houghton, Jonathan D R, Iitembu, Johannes A, Isaacs, Moenieba, Isahaku, Sadique, Ishimura, Gakushi, Islam, Monirul, Issifu, Ibrahim, Jackson, Jeremy, Jacquet, Jennifer, Jensen, Olaf P, Ramon, Jorge Jimenez, Jin, Xue, Jonah, Alberta, Jouffray, Jean-Baptiste, Juniper, S Kim, Jusoh, Sufian, Kadagi, Isigi, Kaeriyama, Masahide, Kaiser, Michel J, Kaiser, Brooks Alexandra, Kakujaha-Matundu, Omu, Karuaihe, Selma T, Karumba, Mary, Kemmerly, Jennifer D, Khan, Ahmed S, Kimani, Patrick, Kleisner, Kristin, Knowlton, Nancy, Kotowicz, Dawn, Kurien, John, Kwong, Lian E, Lade, Steven, Laffoley, Dan, Lam, Mimi E, Lam, Vicky W L, Lange, Glenn-Marie, Latif, Mohd T, Le Billon, Philippe, Le Brenne, Valérie, Le Manach, Frédéric, Levin, Simon A, Levin, Lisa, Limburg, Karin E, List, John, Lombard, Amanda T, Lopes, Priscila F M, Lotze, Heike K, Mallory, Tabitha G, Mangar, Roshni S, Marszalec, Daniel, Mattah, Preciou, Mayorga, Juan, McAusland, Carol, McCauley, Douglas J, McLean, Jeffrey, McMullen, Karly, Meere, Frank, Mejaes, Annie, Melnychuk, Michael, Mendo, Jaime, Micheli, Fiorenza, Millage, Katherine, Miller, Dana, Mohamed, Kolliyil Sunil, Mohammed, Essam, Mokhtar, Mazlin, Morgan, Lance, Muawanah, Umi, Munro, Gordon R, Murray, Grant, Mustafa, Saleem, Nayak, Prateep, Newell, Dianne, Nguyen, Tu, Noack, Frederik, Nor, Adibi M, Nunoo, Francis K E, Obura, David, Okey, Tom, Okyere, Isaac, Onyango, Paul, Oostdijk, Maartje, Orlov, Polina, Österblom, Henrik, Owens, Dwight, Owens, Tessa, Oyinlola, Mohammed, Pacoureau, Nathan, Pakhomov, Evgeny, Abrantes, Juliano Palacio, Pascual, Unai, Paulmier, Aurélien, Pauly, Daniel, Pèlèbè, Rodrigue Orobiyi Edéya, Peñalosa, Daniel, Pennino, Maria G, Peterson, Garry, Pham, Thuy T T, Pinkerton, Evelyn, Polasky, Stephen, Polunin, Nicholas V C, Prah, Ekow, Ramírez, Jorge, Relano, Veronica, Reygondeau, Gabriel, Robadue, Don, Roberts, Callum, Rogers, Alex, Roumbedakis, Katina, Sala, Enric, Scheffer, Marten, Segerson, Kathleen, Seijo, Juan Carlo, Seto, Karen C, Shogren, Jason F, Silver, Jennifer J, Singh, Gerald, Soszynski, Ambre, Splichalova, Dacotah-Victoria, Spring, Margaret, Stage, Jesper, Stephenson, Fabrice, Stewart, Bryce D, Sultan, Riad, Suttle, Curti, Tagliabue, Alessandro, Tall, Amadou, Talloni-Álvarez, Nicolá, Tavoni, Alessandro, Taylor, D R Fraser, Teh, Louise S L, Teh, Lydia C L, Thiebot, Jean-Baptiste, Thiele, Torsten, Thilsted, Shakuntala H, Thumbadoo, Romola V, Tigchelaar, Michelle, Tol, Richard S J, Tortell, Philippe, Troell, Max, Uzmanoğlu, M Selçuk, van Putten, Ingrid, van Santen, Gert, Villaseñor-Derbez, Juan Carlo, Wabnitz, Colette C C, Walsh, Melissa, Walsh, J P, Wambiji, Nina, Weber, Elke U, Westley, France, Williams, Stella, Wisz, Mary S, Worm, Bori, Xiao, Lan, Yagi, Nobuyuki, Yamazaki, Satoshi, Yang, Hong, and Zeller, Dirk
Subjects: 0106 biological sciences, Aquatic Ecology and Water Quality Management, Multidisciplinary, WIMEK, 010504 meteorology & atmospheric sciences, Natural resource economics, 530 Physics, 010604 marine biology & hydrobiology, Subsidy, Aquatische Ecologie en Waterkwaliteitsbeheer, 01 natural sciences, WTO, fishery, subsidy, 13. Climate action, 550 Earth sciences & geology, SUBSÍDIOS, Life Science, 14. Life underwater, Business, 0105 earth and related environmental sciences
Abstract: Sustainably managed wild fisheries support food and nutritional security, livelihoods, and cultures (1). Harmful fisheries subsidies—government payments that incentivize overcapacity and lead to overfishing—undermine these benefits yet are increasing globally (2). World Trade Organization (WTO) members have a unique opportunity at their ministerial meeting in November to reach an agreement that eliminates harmful subsidies (3). We—a group of scientists spanning 46 countries and 6 continents—urge the WTO to make this commitment...
Published: 2021

21. ENSO diversity driving low-frequency change in mesoscale activity off Peru and Chile

Author: Véronique Garçon, Ivonne Montes, Joël Sudre, Carlos Conejero, Boris Dewitte, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, purl.org/pe-repo/ocde/ford#1.05.09 [https], [SDE.MCG]Environmental Sciences/Global Changes, Mesoscale meteorology, Magnitude (mathematics), lcsh:Medicine, purl.org/pe-repo/ocde/ford#1.05.10 [https], Physical oceanography, 01 natural sciences, Article, Atmospheric science, 14. Life underwater, lcsh:Science, 0105 earth and related environmental sciences, Multidisciplinary, Upwelling, 010604 marine biology & hydrobiology, lcsh:R, La Niña, Eddy, El Niño, Productivity (ecology), 13. Climate action, purl.org/pe-repo/ocde/ford#1.05.11 [https], Climatology, lcsh:Q, Geology
Abstract: Transient mesoscale oceanic eddies in Eastern Boundary Upwelling Systems are thought to strongly affect key regional scale processes such as ocean heat transport, coastal upwelling and productivity. Understanding how these can be modulated at low-frequency is thus critical to infer their role in the climate system. Here we use 26 years of satellite altimeter data and regional oceanic modeling to investigate the modulation of eddy kinetic energy (EKE) off Peru and Chile by ENSO, the main mode of natural variability in the tropical Pacific. We show that EKE tends to increase during strong Eastern Pacific (EP) El Niño events along the Peruvian coast up to northern Chile and decreases off central Chile, while it is hardly changed during Central Pacific El Niño and La Niña events. However the magnitude of the EKE changes during strong EP El Niño events is not proportional to their strength, with in particular the 1972/1973 El Niño event standing out as an extreme event in terms of EKE increase off Peru reaching an amplitude three times as large as that during the 1997/1998 El Niño event, and the 2015/2016 El Niño having instead a weak impact on EKE. This produces decadal changes in EKE, with a similar pattern than that of strong EP El Niño events, resulting in a significant negative (positive) long-term trend off Peru (central Chile).
Published: 2020

22. Multi-scale coastal surface temperature in the Bay of Biscay and the English Channel

Author: Joël Sudre, François G. Schmitt, Adam Ayouche, Hussein Yahia, Guillaume Charria, Coline Poppeschi, Sébastien Theetten, Véronique Garçon, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Geometry and Statistics in acquisition data (GeoStat), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), LEFE-MANU, CNRS IMECO, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Canyon, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Continental shelf, Mesoscale meteorology, Sea surface temperature, Eddy, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, 13. Climate action, Climatology, 14. Life underwater, Temporal scales, Bay, Channel (geography), Geology
Abstract: The Bay of Biscay and the English Channel, in the North-eastern Atlantic, are considered as a natural laboratory to explore the coastal dynamics at different spatial and temporal scales. In those regions, the coastal circulation is constrained by a complex topography (e.g. varying width of the continental shelf, canyons), river runoffs, strong tides and a seasonally contrasted wind-driven circulation. Based on different numerical model experiments (from 400m to 4km spatial resolution, from 40 to 100 sigma vertical layers using 3D primitive equation ocean models), different features of the Bay of Biscay and English Channel circulation are assessed and explored. Both spatial (submesoscale and mesoscale) and temporal (from hourly to monthly) scales are considered. Modelled spatial scales, with a specific focus on the variability of fine scale features (e.g. fronts, filaments, eddies), are compared with remotely sensed observations (i.e. Sea Surface Temperature). Different methodologies as singularity and Lyapunov exponents allow describing fine scales features and are applied on both modelled and observed datasets. For temporal scales, in situ high frequency surface temperature measurements from coastal moorings (from COAST-HF observing network) provide a reference for the temporal variability to be modelled. Exploring differences in the temporal scales (from an Empirical Mode Decomposition) advises on the efficiency of our coastal modelling approach. This result overview in the Bay of Biscay and the English Channel aims illustrating the input of coastal modelling activities in understanding multi-scale interactions (spatial and temporal).
Published: 2020

23. Small scale transport processes from HF-Radar

Author: Vincent Rossi, Ismael Hernández-Carrasco, Véronique Garçon, and Alejandro Orfila
Subjects: Scale (ratio), law, Environmental science, Radar, law.invention, Remote sensing
Abstract: Coastal ocean ecosystems are major contributor to the global biogeochemical cycles and biological productivity. Physicalfactors induced by the turbulent flow play a crucial role in regulating marine ecosystem. However, while large scale dynamicsin the open ocean is well described by geostrophy, the role of small scale transport processes in coastal regions is stillpoorly understood due to lack of continuous high-resolution observations. Here, the influence of small-scale coastal dynamicson surface phytoplankton structuring is studied using Lagrangian metrics computed from HF Radar currents and satellitechlorophyll-a (Chl). The combination of complementary Lagrangian diagnostics, including the accumulated divergence of theflow along fluid trajectories, provides an improved description of the 3D flow geometry which facilitates the interpretation of twonon-exclusive physical mechanisms affecting phytoplankton patchiness. Attracting submesoscale fronts, unveiled by backwardsLagrangian Coherent Structures, are associated to negative Lagrangian divergence where particles and Chl standing stockscluster. Filaments of positive Lagrangian divergence, representing large accumulated upward vertical velocities and suggestingaccrued injection of subsurface nutrients, match areas with large Chl concentrations. Our findings demonstrate that an accuratedescription of small-scale transport processes is necessary to comprehend bio-physical interactions in coastal seas and toestimate biological productivity.
Published: 2020

24. Effects of upwelling duration and phytoplankton growth regime on dissolved-oxygen levels in an idealized Iberian Peninsula upwelling system

Author: Véronique Garçon, Yves Morel, João H. Bettencourt, Peter H. Haynes, Lionel Renault, Vincent Rossi, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Haynes, Peter [0000-0002-7726-6988], Apollo - University of Cambridge Repository, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: 0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Population, 01 natural sciences, Sink (geography), Nutrient, Phytoplankton, 14. Life underwater, lcsh:Science, education, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, education.field_of_study, geography.geographical_feature_category, 010604 marine biology & hydrobiology, lcsh:QC801-809, Hypoxia (environmental), Primary production, 15. Life on land, 14 Life Below Water, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Oceanography, 13. Climate action, Environmental science, Upwelling, lcsh:Q, lcsh:Physics
Abstract: We apply a coupled modelling system composed of a state-of-the-art hydrodynamical model and a low-complexity biogeochemical model to an idealized Iberian Peninsula upwelling system to identify the main drivers of dissolved-oxygen variability and to study its response to changes in the duration of the upwelling season and in the phytoplankton growth regime. We find that the export of oxygenated waters by upwelling front turbulence is a major sink for nearshore dissolved oxygen. In our simulations of summer upwelling, when the phytoplankton population is generally dominated by diatoms whose growth is boosted by nutrient input, net primary production and air–sea exchange compensate dissolved-oxygen depletion by offshore export over the shelf. A shorter upwelling duration causes a relaxation of upwelling winds and a decrease in offshore export, resulting in a slight increase of net dissolved-oxygen enrichment in the coastal region as compared to longer upwelling durations. When phytoplankton is dominated by groups less sensitive to nutrient inputs, growth rates decrease, and the coastal region becomes net heterotrophic. Together with the physical sink, this lowers the net oxygenation rate of coastal waters, which remains positive only because of air–sea exchange. These findings help in disentangling the physical and biogeochemical controls of dissolved oxygen in upwelling systems and, together with projections of increased duration of upwelling seasons and phytoplankton community changes, suggest that the Iberian coastal upwelling region may become more vulnerable to hypoxia and deoxygenation.
Published: 2020

25. Under‐Ice Phytoplankton Blooms in the Central Arctic Ocean: Insights From the First Biogeochemical IAOOS Platform Drift in 2017

Author: Cécilia Bertosio, Christine Provost, Nathalie Sennéchael, Zoé Koenig, Marylou Athanase, Véronique Garçon, Elisabeth Boles, Austral, Boréal et Carbone (ABC), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), ANR-10-EQPX-0032,IAOOS,Système d'observation de la glace, de l'atmopshère et de l'océan en Arctique(2010), ANR-14-AORS-0003,PAN-ARCTIC OPTIONS,PAN-ARTIC OPTIONS: HOLISTIC INTEGRATION FOR ARCTIC COASTAL-MARINE SUSTAINABILITY(2014), European Project: 603887,EC:FP7:ENV,FP7-ENV-2013-two-stage,ICE-ARC(2014), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
Subjects: 0106 biological sciences, under ice, 010504 meteorology & atmospheric sciences, Nansen Basin, [SDE.MCG]Environmental Sciences/Global Changes, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Oceanography, 01 natural sciences, Algal bloom, biogeochemistry Central Arctic Ocean, Geochemistry and Petrology, Phytoplankton, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, 010604 marine biology & hydrobiology, phytoplankton bloom, 15. Life on land, Spring bloom, Snow, Colored dissolved organic matter, Geophysics, Arctic, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Environmental science, Bloom, Eurasian Basin, primary production
Abstract: International audience; In April 2017, the first Ice Atmosphere Arctic Ocean Observing System (IAOOS) platform equipped with biogeochemical sensors was deployed near the North Pole. Over the next 8 months it meandered southward with the ice, collecting measurements in the upper 250 m of Amundsen Basin, the Gakkel Ridge, Nansen Basin, and Fram Strait. Two distinct periods of primary production were encountered. The first bloom developed in the mixed layer in Amundsen Basin in May, reaching maximum chlorophyll a concentrations on the order of ~ 0.5 mg m−3 by the end of June. This bloom occurred earlier in the year than any other recorded bloom in Amundsen Basin, despite very limited under‐ice light due to a thick layer of snow. The second bloom, encountered in Nansen Basin in August, was significantly larger (mean profile maximum chlorophyll a was 1.45 mg m−3). Examinations of the optical community index and colored dissolved organic matter concentrations suggest that the spring bloom consisted of small phytoplankton which may have been mixotrophic, while the summer bloom contained a greater diversity of planktonic size classes. The data set demonstrates the heterogeneity of Arctic under‐ice primary production, and is a valuable resource for validating coupled Earth System models.
Published: 2020

26. Seasonal Variability of the Southern Tip of the Oxygen Minimum Zone in the Eastern South Pacific (30°‐38°S): A Modeling Study

Author: Aurélien Paulmier, Ivonne Montes, Véronique Garçon, Matias Pizarro-Koch, Oscar Pizarro, Boris Dewitte, Marcel Ramos, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Oxygen minimum zone, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Oxygen budget, Eddy fluxes, Oceanography, 01 natural sciences, purl.org/pe-repo/ocde/ford#1.05.00 [http], Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Peru‐Chile Undercurrent, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, purl.org/pe-repo/ocde/ford#1.05.09 [http], Thesaurus (information retrieval), 010505 oceanography, purl.org/pe-repo/ocde/ford#1.05.11 [http], Geophysics, 13. Climate action, Space and Planetary Science, Peru-Chile Undercurrent, Environmental science, Eastern South Pacific
Abstract: We investigate the seasonal variability of the southern tip (30 degrees-38 degrees S) of the eastern South Pacific oxygen minimum zone (OMZ) based on a high horizontal resolution (1/12 degrees) regional coupled physical-biogeochemical model simulation. The simulation is validated by available in situ observations and the OMZ seasonal variability is documented. The model OMZ, bounded by the contour of 45 mu M, occupies a large volume (4.5x10(4) km(3)) during the beginning of austral winter and a minimum (3.5x10(4) km(3)) at the end of spring, just 1 and 2 months after the southward transport of the Peru-Chile Undercurrent (PCUC) is maximum and minimum, respectively. We showed that the PCUC significantly impacts the alongshore advection of dissolved oxygen (DO) modulating the OMZ seasonal variability. However, zonal transport of DO by meridionally alternating zonal jets and mesoscale eddy fluxes play also a major role in the seasonal and spatial variability of the OMZ. Consistently, a DO budget analysis reveals a significant contribution of advection terms to the rate of change of DO and the prominence of mesoscale variability within the seasonal cycle of these terms. Biogeochemical processes and horizontal and vertical mixing, associated with subgrid scale processes, play only a secondary role in the OMZ seasonal cycle. Overall, our study illustrates the interplay of mean and (mesoscale) eddy-induced transports of DO in shaping the OMZ and its seasonal cycle off Central Chile.
Published: 2019

27. Oxygen

Author: Véronique Garçon, Marilaure Grégoire, Kirsten Isensee, and Johannes Karstensen
Published: 2019

28. In search for the sources of plastic marine litter that contaminates the Easter Island Ecoregion

Author: Martin Thiel, Carlos F. Gaymer, Yann Drillet, Boris Dewitte, Beatriz Yannicelli, Nicolas C. Ory, Simon Jan van Gennip, Véronique Garçon, Ekaterina Popova, Marcel Ramos, Guillermo Luna-Jorquera, Luis Bravo, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Microplastics, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, lcsh:Medicine, Marine life, 010501 environmental sciences, 01 natural sciences, Article, Environmental impact, Ecoregion, Ocean gyre, Marine debris, 14. Life underwater, lcsh:Science, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Shore, geography, Multidisciplinary, geography.geographical_feature_category, Physical oceanography, lcsh:R, Ocean current, Debris, Oceanography, 13. Climate action, Environmental science, lcsh:Q
Abstract: Subtropical gyres are the oceanic regions where plastic litter accumulates over long timescales, exposing surrounding oceanic islands to plastic contamination, with potentially severe consequences on marine life. Islands’ exposure to such contaminants, littered over long distances in marine or terrestrial habitats, is due to the ocean currents that can transport plastic over long ranges. Here, this issue is addressed for the Easter Island ecoregion (EIE). High-resolution ocean circulation models are used with a Lagrangian particle-tracking tool to identify the connectivity patterns of the EIE with industrial fishing areas and coastline regions of the Pacific basin. Connectivity patterns for “virtual” particles either floating (such as buoyant macroplastics) or neutrally-buoyant (smaller microplastics) are investigated. We find that the South American shoreline between 20°S and 40°S, and the fishing zone within international waters off Peru (20°S, 80°W) are associated with the highest probability for debris to reach the EIE, with transit times under 2 years. These regions coincide with the most-densely populated coastal region of Chile and the most-intensely fished region in the South Pacific. The findings offer potential for mitigating plastic contamination reaching the EIE through better upstream waste management. Results also highlight the need for international action plans on this important issue.
Published: 2019

29. Seasonal variability of the oxygen minimum zone off Peru in a high-resolution regional coupled model

Author: Marcel Ramos, Véronique Garçon, Oscar Pizarro, Oscar Vergara, Aurélien Paulmier, Ivonne Montes, and Boris Dewitte
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:Life, Mesoscale meteorology, Eddy covariance, Flux, Energy flux, Seasonal variations, Oceanography, Oxygen minimum zone, 01 natural sciences, purl.org/pe-repo/ocde/ford#1.05.00 [http], lcsh:QH540-549.5, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, purl.org/pe-repo/ocde/ford#1.05.09 [http], 010604 marine biology & hydrobiology, lcsh:QE1-996.5, Rossby wave, lcsh:Geology, purl.org/pe-repo/ocde/ford#1.05.11 [http], lcsh:QH501-531, Eddy, Environmental science, Upwelling, lcsh:Ecology, Minimum oxygen zones
Abstract: In addition to being one of the most productive upwelling systems, the oceanic region off Peru is embedded in one of the most extensive oxygen minimum zones (OMZs) of the world ocean. The dynamics of the OMZ off Peru remain uncertain, partly due to the scarcity of data and to the ubiquitous role of mesoscale activity on the circulation and biogeochemistry. Here we use a high-resolution coupled physical/biogeochemical model simulation to investigate the seasonal variability of the OMZ off Peru. The focus is on characterizing the seasonal cycle in dissolved O2 (DO) eddy flux at the OMZ boundaries, including the coastal domain, viewed here as the eastern boundary of the OMZ, considering that the mean DO eddy flux in these zones has a significant contribution to the total DO flux. The results indicate that the seasonal variations of the OMZ can be interpreted as resulting from the seasonal modulation of the mesoscale activity. Along the coast, despite the increased seasonal low DO water upwelling, the DO peaks homogeneously over the water column and within the Peru Undercurrent (PUC) in austral winter, which results from mixing associated with the increase in both the intraseasonal wind variability and baroclinic instability of the PUC. The coastal ocean acts therefore as a source of DO in austral winter for the OMZ core, through eddy-induced offshore transport that is also shown to peak in austral winter. In the open ocean, the OMZ can be divided vertically into two zones: an upper zone above 400 m, where the mean DO eddy flux is larger on average than the mean seasonal DO flux and varies seasonally, and a lower part, where the mean seasonal DO flux exhibits vertical–zonal propagating features that share similar characteristics than those of the energy flux associated with the annual extratropical Rossby waves. At the OMZ meridional boundaries where the mean DO eddy flux is large, the DO eddy flux has also a marked seasonal cycle that peaks in austral winter (spring) at the northern (southern) boundary. In the model, the amplitude of the seasonal cycle is 70 % larger at the southern boundary than at the northern boundary. Our results suggest the existence of distinct seasonal regimes for the ventilation of the OMZ by eddies at its boundaries. Implications for understanding the OMZ variability at longer timescales are discussed.
Published: 2016

30. Simulation of an artificial upwelling using immersed in situ phytoplankton microcosms

Author: Marie Boye, Denis de la Broise, Anne Donval, Mélanie Giraud, Véronique Garçon, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and France Energies Marines [Brest]
Subjects: 0106 biological sciences, Ocean Thermal Energy Conversion, Chlorophyll a, Microcosms, 010504 meteorology & atmospheric sciences, growth, Population, coastal waters, prochlorococcus, Aquatic Science, 01 natural sciences, surface waters, chemistry.chemical_compound, pacific, Phytoplankton, Incubation experiment, north-atlantic, 14. Life underwater, Artificial upwelling, diatom blooms, education, Ecology, Evolution, Behavior and Systematics, atlantic-ocean, 0105 earth and related environmental sciences, education.field_of_study, biology, Ecology, ACL, nutrient, 010604 marine biology & hydrobiology, Food web, biology.organism_classification, Oceanography, chemistry, Intertropical area, Upwelling, Seawater, Prochlorococcus, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Microcosm, Martinique
Abstract: 00000 ăWOS:000369212600010; International audience; The inflow of deep seawater in the surface layer by an Ocean Thermal Energy Conversion (OTEC) plant will generate artificial upwelling. In order to study the potential impact on biogeochemical processes that could result, in situ microcosms were designed to simulate seawater plant discharge and these were deployed off the Caribbean coast of Martinique. Seawater was collected in ultra-clean conditions at maximum chlorophyll a concentrations (45 m depth). The water was then mixed with either 2% or 10% deep seawater (1100 m depth) and put in 2.3 L polycarbonate bottles. These microcosms were immersed for 6 days at 45 m depth on a 220 m mooring. Samples from the surrounding environment and from the microcosms were analyzed by pigment quantification, counting of picophytoplankton groups and macronutrient analyses. Similar trends in the evolutions of the phytoplankton populations were observed over time between the control microcosms (without addition of deep seawater) and the surrounding environment, suggesting that these microcosms can be used as a realistic representation of the natural surrounding waters over a 6-day incubation period. Microcosm enrichment with 10% deep seawater induced a shift in the phytoplankton assemblage towards the development of diatoms, haptophytes, and Prochlorococcus, whereas 2% enrichment only led to an increase in the Prochlorococcus population.
Published: 2016

31. Potential effects of deep seawater discharge by an Ocean Thermal Energy Conversion plant on the marine microorganisms in oligotrophic waters

Author: Marie Boye, Stéphane L'Helguen, Véronique Garçon, Denis de la Broise, Joël Sudre, Mélanie Giraud, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), France Energies Marines [Brest], Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Environmental Engineering, 010504 meteorology & atmospheric sciences, Ocean thermal energy conversion, 020209 energy, 02 engineering and technology, 010501 environmental sciences, Regional Ocean Modeling System, 01 natural sciences, 7. Clean energy, Water column, Phytoplankton, Solar Energy, 0202 electrical engineering, electronic engineering, information engineering, Environmental Chemistry, Martinique, Seawater, Photic zone, Renewable Energy, Environmental standards, 14. Life underwater, Waste Management and Disposal, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Microbiota, ACL, Temperature, Modeling, Biogeochemistry, Plankton, Artificial seawater discharge in situ experiments, Pollution, 6. Clean water, Marine microbial ecosystem, Oceanography, Pilot plant, Caribbean Region, 13. Climate action, [SDE]Environmental Sciences, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; Installation of an Ocean Thermal Energy Conversion pilot plant (OTEC) off the Caribbean coast of Martinique is expected to use approximately 100 000 m 3 h-1 of deep seawater for its functioning. This study examined the potential effects of the cold nutrient-rich deep seawater discharge on the phytoplankton community living in the surface warm oligotrophic waters before the installation of the pilot plant. Numerical simulations of deep seawater upwelled by the OTEC, showed that a 3.0 °C temperature change, considered as a critical threshold for temperature impact, was never reached during an annual cycle on the top 150 m of the water column on two considered sections centered on the OTEC. The thermal effect should be limited, less than 1 km 2 on the area exhibited a temperature difference of 0.3 °C (absolute value), producing a negligible thermic impact on the phytoplankton assemblage. The impact on phytoplankton of the resulting mixed deep and surface seawater was evaluated by in situ microcosm experiments. Two scenarios of water mix ratio (2 % and 10 % of deep water) were tested at two incubation depths (deep chlorophyll-a maximum: DCM and bottom of the euphotic layer: BEL). The larger impact was obtained at DCM for the highest deep seawater addition (10 %), with a development of diatoms and haptophytes, whereas 2 % addition induced only a limited change of the phytoplankton community (relatively higher Prochlorococcus sp. abundance, but without significant shift of the assemblage). This study suggested that the OTEC plant would significantly modify the phytoplankton assemblage with a shift from pico-phytoplankton toward micro-phytoplankton only in the case of a discharge affecting the DCM and would be restricted to a local scale. Since the lower impact on the phytoplankton assemblage was obtained at BEL, this depth can be recommended for the discharge of the deep seawater to exploit the OTEC plant
Published: 2018

32. Effect of wind stress forcing on ocean dynamics at air-sea interface

Author: Hussein Yahia, Christophe Maes, Véronique Garçon, Joël Sudre, Geometry and Statistics in acquisition data (GeoStat), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), SOLAS Surface ocean lower atmosphere study, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: COURANT D'EKMAN, Singularity spectrum, 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Wind stress, 02 engineering and technology, Wavelets, 01 natural sciences, DYNAMIQUE DE L'EAU, TRAITEMENT DU SIGNAL, Geostrophic current, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Physics::Atmospheric and Oceanic Physics, ANALYSE STATISTIQUE, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Turbulence, TELEDETECTION SPATIALE, Remote sensing, Hardware and Architecture, Vector field, Geology, Ekman currents, OCEANOGRAPHIE PHYSIQUE, Signal processing, Radar altimetry, Computer Networks and Communications, Statistical tools, Geostrophy, Physics::Geophysics, Ocean dynamics, TURBULENCE MARINE, Ekmann transport, 14. Life underwater, Electrical and Electronic Engineering, Pressure gradient, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, kurtosis, Ocean current, Geophysics, Vorticity, INTERFACE OCEAN ATMOSPHERE, 13. Climate action, [NLIN.NLIN-CD]Nonlinear Sciences [physics]/Chaotic Dynamics [nlin.CD], COURANT MARIN, TENSION DU VENT, Multifractal formalism
Abstract: International audience; We evidence and study the differences in turbulence statistics in ocean dynamics carried by wind forcing at the air-sea interface. Surface currents at the air-sea interaction are of crucial importance because they transport heat from low to high latitudes. At first order, oceanic currents are generated by the balance of the Coriolis and pressure gradient forces (geostrophic current) and the balance of the Coriolis and the frictional forces dominated by wind stress (Ekman current) in the surface ocean layers. The study was conducted by computing statistical moments on the shapes of spectra computed within the framework of microcanonical multi-fractal formalism. Remotely sensed daily datasets derived from one year of altimetry and wind data were used in this study, allowing for the computation of two kinds of vector fields: geostrophy with and geostrophy without wind stress forcing. We explore the statistical properties of singularity spectra computed from velocity norms and vorticity data, notably in relation with kurtosis information to underline the differences in the turbulent regimes associated with both kinds of velocity fields.
Published: 2018

33. Effect of small scale transport processes on phytoplankton distribution in coastal seas

Author: Vincent Rossi, Alejandro Orfila, Véronique Garçon, Ismael Hernández-Carrasco, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), SOCIB Balearic Islands Coastal Ocean Observing and Forecasting System, Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biogeochemical cycle, Multidisciplinary, 010504 meteorology & atmospheric sciences, 010505 oceanography, Turbulence, Science, Mesoscale meteorology, 15. Life on land, 01 natural sciences, Divergence, Oceanography, Productivity (ecology), [SDU]Sciences of the Universe [physics], 13. Climate action, Phytoplankton, Medicine, Environmental science, Marine ecosystem, Ecosystem, 14. Life underwater, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences
Abstract: International audience; Coastal ocean ecosystems are major contributors to the global biogeochemical cycles and biological productivity. Physical factors induced by the turbulent flow play a crucial role in regulating marine ecosystems. However, while large-scale open-ocean dynamics is well described by geostrophy, the role of multiscale transport processes in coastal regions is still poorly understood due to the lack of continuous high-resolution observations. Here, the influence of small-scale dynamics (O(3.5-25) km, i.e. spanning upper submesoscale and mesoscale processes) on surface phytoplankton derived from satellite chlorophyll-a (Chl-a) is studied using Lagrangian metrics computed from High-Frequency Radar currents. The combination of complementary Lagrangian diagnostics, including the Lagrangian divergence along fluid trajectories, provides an improved description of the 3D flow geometry which facilitates the interpretation of two non-exclusive physical mechanisms affecting phytoplankton dynamics and patchiness. Attracting small-scale fronts, unveiled by backwards Lagrangian Coherent Structures, are associated to negative divergence where particles and Chl-a standing stocks cluster. Filaments of positive divergence, representing large accumulated upward vertical velocities and suggesting accrued injection of subsurface nutrients, match areas with large Chl-a concentrations. Our findings demonstrate that an accurate characterization of small-scale transport processes is necessary to comprehend bio-physical interactions in coastal seas. Coastal marine ecosystems have received increasing attention in the last decades due to their important contribution to the global carbon budget 1 , to the world ocean's primary production 2 and to withdraw the global fisheries 3. The hydrodynamics in coastal areas is characterized by a complex interaction of multiscale processes where the energetic inputs from the atmosphere balance with the dissipation at the coast and at the seabed, resulting in specific dynamical features whose spatial and temporal characteristics cover a wide range of scales which differ from those of the open ocean 4,5. These multiscale dynamical processes have profound consequences on the transport and dispersion of biogeochemical tracers, whose knowledge is crucial to understand the mechanisms regulating marine ecosystem (see Martin, 2002 6 and Mahadevan 7 for reviews). In general, fluxes of nutrients into the depleted surface layers of both open and coastal oceans depend on the occurrence and magnitude of vertical motions as well as on horizontal advection patterns and small-scale filaments from distant nutrient-rich regions 6-8. In oligotrophic regions, mesoscale dynamical structures have been related to chlorophyll distribution 9 , sea bird foraging behavior 10 and vertical transport 11. In eutrophic regions, the role of mesoscale turbulence on surface phytoplankton was studied from satellite-derived currents 12 and based on model outputs 13. Contrarily to what is expected in the open ocean, both latter studies documented an anti-correlation between mixing and chlorophyll-a biomass in eastern-boundary upwelling zones. The overall effect of mesoscale eddies reducing near-shore productivity in upwelling systems was corroborated by Gruber et al. 14 , using satellite data together with coupled simulations. However, little is known about bio-physical interactions within coastal regions not forced by upwelling-favourable trade winds. Recents studies using drifter observations 15-17 and numerical models 18-22 have shown that submesoscale processes play an important role on the dispersal and transport of tracers. Submesoscale refers to length-scales that
Published: 2018

34. Supplementary material to 'Modulation of the vertical particles transfer efficiency in the Oxygen Minimum Zone off Peru'

Author: Marine Bretagnon, Aurélien Paulmier, Véronique Garçon, Boris Dewitte, Sérena Illig, Nathalie Leblond, Laurent Coppola, Fernando Campos, Frederico Velazco, Christos Panagiotopoulos, Andreas Oschlies, Martin Jose Hernandez-Ayon, Helmut Maske, Oscar Vergara, Ivonne Montes, Philippe Martinez, Edgardo Carasco, Jacques Grelet, Olivier Desprez-De-Gesincourt, Christophe Maes, and Lionel Scouarnec
Published: 2018

35. Modulation of the vertical particles transfer efficiency in the Oxygen Minimum Zone off Peru

Author: Marine Bretagnon, Aurélien Paulmier, Véronique Garçon, Boris Dewitte, Sérena Illig, Nathalie Leblond, Laurent Coppola, Fernando Campos, Frederico Velazco, Christos Panagiotopoulos, Andreas Oschlies, Martin Jose Hernandez-Ayon, Helmut Maske, Oscar Vergara, Ivonne Montes, Philippe Martinez, Edgardo Carasco, Jacques Grelet, Olivier Desprez-De-Gesincourt, Christophe Maes, and Lionel Scouarnec
Abstract: The fate of the Organic Matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth’s system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive Eastern Boundary Upwelling Systems (EBUSs) associated with Oxygen Minimum Zones (OMZs) should foster OM preservation due to low O2 conditions, but their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru, providing high temporal resolution O2 series characterizing two seasonal steady states at the upper trap: suboxic ([O2]
Published: 2018

36. Declining oxygen in the global ocean and coastal waters

Author: Michael R. Roman, Moriaki Yasuhara, S. W. A. Naqvi, Lisa A. Levin, Jing Zhang, Denise L. Breitburg, Daniel J. Conley, Denis Gilbert, Maciej Telszewski, Andreas Oschlies, Francisco P. Chavez, Ivonne Montes, Nancy N. Rabalais, Kenneth A. Rose, Brad A. Seibel, Kirsten Isensee, Marilaure Grégoire, Karin E. Limburg, Grant C. Pitcher, Dimitri Gutiérrez, Gil S. Jacinto, and Véronique Garçon
Subjects: purl.org/pe-repo/ocde/ford#6.03.01 [https], 0106 biological sciences, Ocean deoxygenation, Aquatic Organisms, Conservation of Natural Resources, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Oceans and Seas, Adaptation, Biological, Fisheries, Climate change, Global Warming, 01 natural sciences, Animals, Seawater, Temporal scales, 0105 earth and related environmental sciences, Multidisciplinary, purl.org/pe-repo/ocde/ford#6.01.01 [https], 010604 marine biology & hydrobiology, Global warming, Oxygen, Oceanography, Greenhouse gas, Upwelling, Climate model, Environmental Monitoring
Abstract: BACKGROUND Oxygen concentrations in both the open ocean and coastal waters have been declining since at least the middle of the 20th century. This oxygen loss, or deoxygenation, is one of the most important changes occurring in an ocean increasingly modified by human activities that have raised temperatures, CO 2 levels, and nutrient inputs and have altered the abundances and distributions of marine species. Oxygen is fundamental to biological and biogeochemical processes in the ocean. Its decline can cause major changes in ocean productivity, biodiversity, and biogeochemical cycles. Analyses of direct measurements at sites around the world indicate that oxygen-minimum zones in the open ocean have expanded by several million square kilometers and that hundreds of coastal sites now have oxygen concentrations low enough to limit the distribution and abundance of animal populations and alter the cycling of important nutrients. ADVANCES In the open ocean, global warming, which is primarily caused by increased greenhouse gas emissions, is considered the primary cause of ongoing deoxygenation. Numerical models project further oxygen declines during the 21st century, even with ambitious emission reductions. Rising global temperatures decrease oxygen solubility in water, increase the rate of oxygen consumption via respiration, and are predicted to reduce the introduction of oxygen from the atmosphere and surface waters into the ocean interior by increasing stratification and weakening ocean overturning circulation. In estuaries and other coastal systems strongly influenced by their watershed, oxygen declines have been caused by increased loadings of nutrients (nitrogen and phosphorus) and organic matter, primarily from agriculture; sewage; and the combustion of fossil fuels. In many regions, further increases in nitrogen discharges to coastal waters are projected as human populations and agricultural production rise. Climate change exacerbates oxygen decline in coastal systems through similar mechanisms as those in the open ocean, as well as by increasing nutrient delivery from watersheds that will experience increased precipitation. Expansion of low-oxygen zones can increase production of N 2 O, a potent greenhouse gas; reduce eukaryote biodiversity; alter the structure of food webs; and negatively affect food security and livelihoods. Both acidification and increasing temperature are mechanistically linked with the process of deoxygenation and combine with low-oxygen conditions to affect biogeochemical, physiological, and ecological processes. However, an important paradox to consider in predicting large-scale effects of future deoxygenation is that high levels of productivity in nutrient-enriched coastal systems and upwelling areas associated with oxygen-minimum zones also support some of the world’s most prolific fisheries. OUTLOOK Major advances have been made toward understanding patterns, drivers, and consequences of ocean deoxygenation, but there is a need to improve predictions at large spatial and temporal scales important to ecosystem services provided by the ocean. Improved numerical models of oceanographic processes that control oxygen depletion and the large-scale influence of altered biogeochemical cycles are needed to better predict the magnitude and spatial patterns of deoxygenation in the open ocean, as well as feedbacks to climate. Developing and verifying the next generation of these models will require increased in situ observations and improved mechanistic understanding on a variety of scales. Models useful for managing nutrient loads can simulate oxygen loss in coastal waters with some skill, but their ability to project future oxygen loss is often hampered by insufficient data and climate model projections on drivers at appropriate temporal and spatial scales. Predicting deoxygenation-induced changes in ecosystem services and human welfare requires scaling effects that are measured on individual organisms to populations, food webs, and fisheries stocks; considering combined effects of deoxygenation and other ocean stressors; and placing an increased research emphasis on developing nations. Reducing the impacts of other stressors may provide some protection to species negatively affected by low-oxygen conditions. Ultimately, though, limiting deoxygenation and its negative effects will necessitate a substantial global decrease in greenhouse gas emissions, as well as reductions in nutrient discharges to coastal waters.
Published: 2018

37. Square wave voltammetry measurements of low concentrations of nitrate using Au/AgNPs electrode in chloride solutions

Author: Véronique Garçon, C. Barus, D. Chen Legrand, Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS NOUMEA), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR065-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Projet MIACTIS financé par le RTRA-STAE
Subjects: Working electrode, Inorganic chemistry, Analytical chemistry, 02 engineering and technology, 01 natural sciences, Chloride, Electrocatalytic, Silver nanoparticle, Analytical Chemistry, chemistry.chemical_compound, Nitrate, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Electrochemistry, medicine, Environmental Chemistry, Bimetallic strip, 010401 analytical chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Square Wave Voltammetry, chemistry, Saturated calomel electrode, Electrode, Nanoparticles, Cyclic voltammetry, 0210 nano-technology, Nitrate detection, medicine.drug
Abstract: International audience; The aim of this work is to highlight the potential of using a modified gold electrode with controlled quantity of silver nanoparticles as a working electrode to detect low concentrations of nitrate in chloride solutions. Optimal charge for silver deposition has been determined to obtain the highest signal for the nitrate reduction as the electrocatalytic properties of the bimetallic electrode were directly influenced by its composition. According to the Volcano plot obtained the charge chosen was -52 µC for a 3 mm diameter electrode, corresponding to 4.6 x 1015 Ag atoms cm-2. It has been shown that dioxygen did not participate to the nitrate reduction mechanism. In order to decrease the limit of quantification, square wave voltammetry was preferred to less sensitive cyclic voltammetry. Nitrate was quantified in chloride solutions in the concentration range found in the open ocean, i.e. 0.39-50 µmol L-1 with a good linear regression (R2=0.9969). The stability of the bimetallic Au-Ag systems has been evaluated and showed almost no difference on the signal recorded over a 26 days period which is suitable to consider an in situ sensor development for marine applications.
Published: 2017

38. Reconstruction of super-resolution ocean pCO2 and air–sea fluxes of CO2 from satellite imagery in the southeastern Atlantic

Author: Christoph S. Garbe, Serena Illig, Juana Magdalena Santana-Casiano, Hussein Yahia, Boris Dewitte, Melchor González-Dávila, I. Hernandez-Carrasco, Joël Sudre, Véronique Garçon, Isabelle Dadou, and Aurélien Paulmier
Subjects: Sea surface temperature, Nonlinear system, Flux (metallurgy), Wavelet, Cascade, Climatology, Climate change, Environmental science, Satellite imagery, Submarine pipeline, Physics::Atmospheric and Oceanic Physics, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes
Abstract: An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) requires to access the high-resolution of the GHG air–sea flux at the interface. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO2 ( pCO2) and air–sea CO2 fluxes at super resolution (4 km, i.e., 1/32° at these latitudes) using sea surface temperature (SST) and ocean color (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution pCO2 and air–sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the microcanonical multifractal formalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multi-resolution analysis performed on the signal of the so-called singularity exponents allows for the correct and near optimal cross-scale inference of GHG fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela area. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small-scale variability. We examine different combinations of ocean color and sea surface temperature products in order to increase the number of valid points and the quality of the inferred pCO2 field. The methodology is validated using in situ measurements by means of statistical errors. We find that mean absolute and relative errors in the inferred values of pCO2 with respect to in situ measurements are smaller than for CarbonTracker.
Published: 2015

39. Long-term variability of phytoplankton carbon biomass in the Sargasso Sea

Author: Michael W. Lomas, Véronique Garçon, Philip Wallhead, and John Casey
Subjects: Atmospheric Science, Global and Planetary Change, Biomass (ecology), fungi, Biological pump, chemistry.chemical_element, Biology, Oceanography, Nutrient, Productivity (ecology), chemistry, North Atlantic oscillation, Grazing, Phytoplankton, Environmental Chemistry, Carbon, General Environmental Science
Abstract: Time series of phytoplankton carbon biomass are scarce yet may provide important insights into ocean productivity and carbon export to depth via the oceanic biological pump. We combine recent flow-cytometric measurements with pigment concentrations and other standard measurements to reconstruct taxon-specific phytoplankton carbon biomass in the Sargasso Sea over 22 years, using a multiple regression approach. The reconstructed series reveal an increasing trend (~3% per year) in total phytoplankton carbon, apparently driven by increasing nutrient supply by vertical mixing associated with a shift to a negative phase in the winter North Atlantic Oscillation index. Also, the reconstructed eukaryote biomass fraction shows a multiannual shift from ~45% in the early 1990s/late 2000s to ~70% in the late 1990s/early 2000s. We hypothesize that a multiannual shift in the seasonal pattern of mixing may have stimulated and restructured the eukaryote community while suppressing prokaryote populations by increasing photodamage and grazing mortality.
Published: 2014

40. Air-sea CO2fluxes above the stratified oxygen minimum zone in the coastal region off Mexico

Author: Emilio Beier, Ana C. Franco, Ramón Sosa-Ávalos, J. Martín Hernández-Ayón, Rubén Castro, Aurélien Paulmier, Véronique Garçon, Helmut Maske, and Jaime Färber-Lorda
Subjects: Advection, Alkalinity, Stratification (water), Subtropics, Oceanography, Oxygen minimum zone, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Dissolved organic carbon, Earth and Planetary Sciences (miscellaneous), Environmental science, 14. Life underwater, Subsurface flow, Surface water
Abstract: Oxygen minimum zones (OMZs) are important sources of CO2 to the atmosphere when physical forces bring subsurface water with high dissolved inorganic carbon (DIC) to the surface. This study examines, for the first time, the influence of the OMZ of the coastal North Eastern Tropical Pacific off Mexico on surface CO2 fluxes. We use variations in the oxycline depth and subsurface water masses to discern physical oceanographic influences. During two cruises, in November 2009 and August 2010, DIC and total alkalinity (TA) measurements were used to estimate pCO2 and air-sea CO2 fluxes. At the OMZ layer, Subtropical Subsurface Water (StSsW) was found to have high pCO2 values (1290 ± 70 μatm). Due to strong vertical stratification, however, the relationship between ΔpCO2 at the air-sea interface and the oxycline/StSsW upper limit depth was weak. During November, the region was a weak source of CO2 to the atmosphere (up to 2.5 mmol C m−2 d−1), while during August a range of values were observed between −4.4 and 3.3 mmol C m−2 d−1). Strong stratification (>1200 J m−3) prevented subsurface mixing of water from the OMZ to the upper layer; particularly in November 2009 which was during an El Nino event. Results suggest that advection of surface water masses, reinforced by strong vertical stratification, controlled surface pCO2, and air-sea CO2 fluxes.
Published: 2014

41. Small-scale features of temperature and salinity surface fields in the Coral Sea

Author: Joël Sudre, D. Varillon, Christophe Maes, Boris Dewitte, and Véronique Garçon
Subjects: 010504 meteorology & atmospheric sciences, 010505 oceanography, Front (oceanography), Temperature salinity diagrams, Context (language use), Oceanography, 01 natural sciences, Western Hemisphere Warm Pool, SSS, Salinity, Sea surface temperature, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Climatology, Earth and Planetary Sciences (miscellaneous), Satellite, 14. Life underwater, Geology, 0105 earth and related environmental sciences
Abstract: The small-scale features in sea surface temperature and salinity fields (SST and SSS) of the Coral Sea are examined using high horizontal spatial and short-term temporal in situ measurements. These features are extracted from thermosalinographs (TSGs) gathered onboard commercial and research vessels and at one long-term fixed station. The analyses are performed along the vessel tracks and the structures of small-scale features are extracted by high-pass spatial filtering the original TSG data. For SSS, it is shown that the features at the scale of mesoscale eddies (approximate to 100 km) vary from about -1.1 to +0.6 psu in the Coral Sea region. Processes sustaining such range include rainfall events, stirring by mesoscale eddies, and the latitudinal displacement of the sharp front associated with the edge of the Western Pacific Warm Pool at the seasonal time scales. The TSG data have revealed the presence of a sharp front (0.4-0.6 psu) between the subtropical and equatorial waters instead of a smooth gradient in the standard SSS climatologies. Within the context of recent remotely sensed observations of salinity, this could represent an important limitation for the validation and calibration of satellite products. In addition to these spatial considerations, temporal variations at one long-term station near Vanuatu show that the coupled air-sea responses to intraseasonal tropical variability, such as the Madden-Julian Oscillation, may have a signature in both SST and SSS fields. However, this response is found to be complex and not necessarily in phase. In the Coral Sea region, our results suggest that MJO-induced variability on SST and SSS exhibit little coherency at the seasonal time scales.
Published: 2013

42. Corrigendum to 'Multi-decadal projections of surface and interior pathways of the Fukushima cesium-137 radioactive plume' [Deep-Sea Res. I 80 (2013) 37–46]

Author: Erik van Sebille, Vincent Rossi, Alex Sen Gupta, Matthew H. England, and Véronique Garçon
Subjects: 010504 meteorology & atmospheric sciences, Climate system, Climate change, 010501 environmental sciences, Aquatic Science, Oceanography, 7. Clean energy, 01 natural sciences, Deep sea, Plume, Geography, 13. Climate action, Research centre, 14. Life underwater, 0105 earth and related environmental sciences
Abstract: a IFISC (Institute for Cross-Disciplinary Physics and Complex Systems), CSIC-UIB, Palma de Mallorca 07122, Spain b Climate Change Research Centre, University of New South Wales, Sydney 2052, Australia c ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney 2052, Australia d Laboratoire d'Etude en Geophysique et Oceanographie Spatiales, CNRS/UPS/IRD/CNES, 14 av. E. Belin, Toulouse 31400, France
Published: 2014

43. SST subseasonal variability in the central Benguela upwelling system as inferred from satellite observations (1999-2009)

Author: Boris Dewitte, Eric Machu, Serena Illig, Véronique Garçon, and Katerina Goubanova
Subjects: 010504 meteorology & atmospheric sciences, 010505 oceanography, Wind stress, Empirical orthogonal functions, Forcing (mathematics), Oceanography, 01 natural sciences, Sea surface temperature, symbols.namesake, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Climatology, Middle latitudes, Earth and Planetary Sciences (miscellaneous), symbols, Environmental science, Upwelling, 14. Life underwater, Antarctic oscillation, Kelvin wave, 0105 earth and related environmental sciences
Abstract: Subseasonal variability of Sea Surface Temperature (SST) in the central Benguela upwelling system is investigated using TMI satellite-derived data over the period 1999-2009. Spatial patterns and time-frequency characteristics of subseasonal variability are documented based on Empirical Orthogonal Functions (EOF) decomposition and wavelet analysis. Despite the land contamination of the TMI satellite data within approximately 100 km off the coast the first EOF of SST anomalies allows characterizing the coastal upwelling variability at the subseasonal scale. Two regimes of variability are evidenced: a submonthly (2-30 days) regime with a dominant 11 days oscillation and a lower frequency intraseasonal (30-90 days) regime with a dominant 61 days oscillation. Both regimes are modulated, to a large extent, by the local surface wind stress and are consistent with Ekman dynamics. The seasonality of the relationship between wind stress and SST for submonthly (intraseasonal) regime is characterized by a marked semiannual (annual) cycle, which is explained in terms of the impact of seasonal change of the upper ocean stratification on the vertical advection process. The wind-driven SST subseasonal variability is shown to be associated with eastward propagating disturbances in the midlatitudes corresponding to a wave number 4. The results also suggest an important role of the Antarctic Oscillation in modulating the intraseasonal wind-driven SST variability. The characteristics of the equatorial intraseasonal Kelvin waves are documented in order to discuss possible impact of remote oceanic forcing on SST variability along the coast in the Benguela upwelling system.
Published: 2013

44. Coupled physical/biogeochemical modeling including O2-dependent processes in the Eastern Boundary Upwelling Systems: application in the Benguela

Author: Isabelle Dadou, Gildas Cambon, Aurélien Paulmier, Joël Sudre, Véronique Garçon, Elodie Gutknecht, Annette Kock, Anita Flohr, Tim Rixen, Eric Machu, B. Le Vu, and Gaute Lavik
Subjects: 0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Advection, 010604 marine biology & hydrobiology, Biogeochemistry, Context (language use), 01 natural sciences, Oceanography, 13. Climate action, Anammox, Upwelling, Environmental science, Nitrification, 14. Life underwater, Nitrogen cycle, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: The Eastern Boundary Upwelling Systems (EBUS) contribute to one fifth of the global catches in the ocean. Often associated with Oxygen Minimum Zones (OMZs), EBUS represent key regions for the oceanic nitrogen (N) cycle. Important bioavailable N loss due to denitrification and anammox processes as well as greenhouse gas emissions (e.g, N2O) occur also in these EBUS. However, their dynamics are currently crudely represented in global models. In the climate change context, improving our capability to properly represent these areas is crucial due to anticipated changes in the winds, productivity, and oxygen content. We developed a biogeochemical model (BioEBUS) taking into account the main processes linked with EBUS and associated OMZs. We implemented this model in a 3-D realistic coupled physical/biogeochemical configuration in the Namibian upwelling system (northern Benguela) using the high-resolution hydrodynamic ROMS model. We present here a validation using in situ and satellite data as well as diagnostic metrics and sensitivity analyses of key parameters and N2O parameterizations. The impact of parameter values on the OMZ off Namibia, on N loss, and on N2O concentrations and emissions is detailed. The model realistically reproduces the vertical distribution and seasonal cycle of observed oxygen, nitrate, and chlorophyll a concentrations, and the rates of microbial processes (e.g, NH4+ and NO2− oxidation, NO3− reduction, and anammox) as well. Based on our sensitivity analyses, biogeochemical parameter values associated with organic matter decomposition, vertical sinking, and nitrification play a key role for the low-oxygen water content, N loss, and N2O concentrations in the OMZ. Moreover, the explicit parameterization of both steps of nitrification, ammonium oxidation to nitrate with nitrite as an explicit intermediate, is necessary to improve the representation of microbial activity linked with the OMZ. The simulated minimum oxygen concentrations are driven by the poleward meridional advection of oxygen-depleted waters offshore of a 300 m isobath and by the biogeochemical activity inshore of this isobath, highlighting a spatial shift of dominant processes maintaining the minimum oxygen concentrations off Namibia. In the OMZ off Namibia, the magnitude of N2O outgassing and of N loss is comparable. Anammox contributes to about 20% of total N loss, an estimate lower than currently assumed (up to 50%) for the global ocean.
Published: 2013

45. On the global estimates of geostrophic and Ekman surface currents

Author: Véronique Garçon, Joël Sudre, and Christophe Maes
Subjects: Momentum (technical analysis), 010504 meteorology & atmospheric sciences, Scale (ratio), 010505 oceanography, Equator, Ocean current, Wind stress, Physical oceanography, Atmospheric sciences, 01 natural sciences, Physics::Geophysics, Geostrophic current, 13. Climate action, Climatology, 14. Life underwater, Physics::Atmospheric and Oceanic Physics, Geostrophic wind, Geology, 0105 earth and related environmental sciences
Abstract: Surface currents in oceanic environments are of crucial importance because they transport momentum, heat, salt, and tracers over large distances that regulate both the local and large-scale climate conditions, and because they contribute to the Lagrangian displacement of floating material, ranging from living resources to marine pollution. In recent decades, the understanding of surface currents has benefited from the opportunity of observing sea level and wind stress via satellite-derived measurements. Combining these parameters into geostrophic and wind-driven components provides an estimate of surface currents with a quarter-degree horizontal resolution at a global scale and at a daily time scale. In the present study, improvements are made on the consideration of the time dependence of the main parameters implied in the determination of the Ekman wind-driven component, and on the treatment of the equatorial singularity. The resulting Geostrophic and Ekman Current Observatory (GEKCO) estimates were validated with independent observations from both Lagrangian and Eulerian perspectives. The statistics of comparison were significant over the globe for the 2000–2008 period. The only exception was the estimation of meridional current along the equator, which requires further developments of the dynamic model and, probably, more accurate measurements. Applications using our GEKCO surface current estimates in cross-disciplinary approaches from physical oceanography to marine ecology are presented and discussed.
Published: 2013

46. Modelling nitrite dynamics and associated feedback processes in the Benguela oxygen minimum zone

Author: Véronique Garçon, Marcello Vichi, T.B. Mashifane, E. Machu, and H.N. Waldron
Subjects: 0301 basic medicine, Benguela, Oxygen minimum zone, Denitrification, 010504 meteorology & atmospheric sciences, Nitrogen assimilation, Nitrite, chemistry.chemical_element, Aquatic Science, Oceanography, 01 natural sciences, 03 medical and health sciences, chemistry.chemical_compound, Anammox, 0105 earth and related environmental sciences, Nitrous oxide, Geology, Nitrogen, 030104 developmental biology, chemistry, Nitrification
Abstract: Understanding nitrite dynamics in oxygen minimum zones (OMZs) is a challenge as it represents an intermediary nitrogen species with a short turnover time. Nitrite is also reduced to nitrogen in OMZs, preventing its accumulation. This creates difficulties in detecting nitrite with colorimetric methods as concentrations may occur below detection limits in some regions. Nitrite concentrations are key to understanding intermediate nitrogen processes and their implication for nitrogen loss in OMZs. A coupled physical-biogeochemical model is applied in the Benguela OMZ to study nitrite dynamics and its associated feedback processes. Simulated results show occurrence of primary and secondary nitrite maxima in the Benguela shelf waters. The primary nitrite maxima in the Benguela are attributed to nitrification and nitrate assimilation as they occur in association with the nitracline. Secondary nitrite maxima accumulate in the Angola-Benguela Front (ABF) OMZ and are attributed to denitrification. The secondary nitrite maxima are consumed by anaerobic ammonium oxidation (anammox) off Walvis Bay. Nitrite maxima are restricted to the shelf off Walvis Bay and advected offshore in the ABF region. Interchanges between the poleward South Atlantic Central Water (SACW) and the equatorward, well–aerated Eastern South Atlantic Central Water (ESACW) drive the seasonality of nitrogen processes in the Benguela. Subsequent nitrite reduction in the Benguela OMZ leads to nitrous oxide production, with high concentrations occurring in the ABF region as a result of nitrification and denitrification. Off Walvis Bay, nitrous oxide production is low since nitrite is consumed by anammox. Nitrous oxide production occurs in thermocline, intermediate and deeper water masses in the ABF region. High N fluxes in the Benguela are attributed to nitrification as compared to anammox and denitrification. Results from this study demonstrate the role of intermediate nitrogen species in nitrogen feedback processes in the Benguela and can be applied in other regions.
Published: 2016

47. Reagentless and calibrationless silicate measurement in oceanic waters

Author: Danièle Thouron, William Giraud, Justyna Jońca, Ludovic Lesven, Véronique Garçon, Margaux Gourdal, Maurice Comtat, Carole Barus, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Géosystèmes - UMR 8157, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie Chimique (LGC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de génie chimique [ancien site de Basso-Cambo] (LGC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Centre National d'Études Spatiales - CNES (FRANCE), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut de Recherche pour le Développement - IRD (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Lille 1, Sciences et Technologies - Lille 1 (FRANCE), and Institut National Polytechnique de Toulouse - INPT (FRANCE)
Subjects: Chimie-Physique, Diffusion, Analytical chemistry, Amperometry, Artificial seawater, Ultramicroelectrode, 010402 general chemistry, 01 natural sciences, Océanographie, Analytical Chemistry, chemistry.chemical_compound, Reagentless, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Molybdenum, Calibrationless, 010401 analytical chemistry, Silicate, Chronoamperometry, 0104 chemical sciences, Microelectrode, chemistry, 13. Climate action, Seawater, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Ferrocyanide
Abstract: International audience; Determination of silicate concentration in seawater without addition of liquid reagents was the key prerequisite for developing an autonomous in situ electrochemical silicate sensor (Lacombe et al., 2007) [11]. The present challenge is to address the issue of calibrationless determination. To achieve such an objective, we chose chronoamperometry performed successively on planar microelectrode (ME) and ultramicroelectrode (UME) among the various possibilities. This analytical method allows estimating simultaneously the diffusion coefficient and the concentration of the studied species. Results obtained with ferrocyanide are in excellent agreement with values of the imposed concentration and diffusion coefficient found in the literature. For the silicate reagentless method, successive chronoamperometric measurements have been performed using a pair of gold disk electrodes for both UME and ME. Our calibrationless method was tested with different concentrations of silicate in artificial seawater from 55 to 140×10−6 mol L−1. The average value obtained for the diffusion coefficient of the silicomolybdic complex is 2.2±0.4×10−6 cm2 s−1, consistent with diffusion coefficient values of molecules in liquid media. Good results were observed when comparing known concentration of silicate with experimentally derived ones. Further work is underway to explore silicate determination within the lower range of oceanic silicate concentration, down to 0.1×10−6 mol L−1.
Published: 2012

48. Surface ocean-lower atmosphere study: Scientific synthesis and contribution to Earth system science

Author: Philip W. Boyd, Birgit Quack, Dorothee C. E. Bakker, Cliff S. Law, Véronique Garçon, Christa A. Marandino, Hermann W. Bange, Patricia K. Quinn, Timothy S. Bates, Martin Johnson, Robert A. Duce, Christopher L. Sabine, Are Olsen, Thomas G. Bell, Emilie H. G. Breviere, and Eric S. Saltzman
Subjects: Ocean, 010504 meteorology & atmospheric sciences, Environmental change, Climate, 010501 environmental sciences, Atmosphere (architecture and spatial design), 01 natural sciences, Multidisciplinary approach, Anthropocene, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, 0105 earth and related environmental sciences, Global and Planetary Change, Flux, Ecology, Scope (project management), business.industry, Atmosphere, Environmental resource management, Biogeochemistry, Earth system science, Processes, Oceanography, 13. Climate action, Environmental science, CLAW hypothesis, business
Abstract: © 2015 The Authors. The domain of the surface ocean and lower atmosphere is a complex, highly dynamic component of the Earth system. Better understanding of the physics and biogeochemistry of the air-sea interface and the processes that control the exchange of mass and energy across that boundary define the scope of the Surface Ocean-Lower Atmosphere Study (SOLAS) project. The scientific questions driving SOLAS research, as laid out in the SOLAS Science Plan and Implementation Strategy for the period 2004-2014, are highly challenging, inherently multidisciplinary and broad. During that decade, SOLAS has significantly advanced our knowledge. Discoveries related to the physics of exchange, global trace gas budgets and atmospheric chemistry, the CLAW hypothesis (named after its authors, Charlson, Lovelock, Andreae and Warren), and the influence of nutrients and ocean productivity on important biogeochemical cycles, have substantially changed our views of how the Earth system works and revealed knowledge gaps in our understanding. As such SOLAS has been instrumental in contributing to the International Geosphere-Biosphere Programme (IGBP) mission of identification and assessment of risks posed to society and ecosystems by major changes in the Earth's biological, chemical and physical cycles and processes during the Anthropocene epoch. SOLAS is a bottom-up organization, whose scientific priorities evolve in response to scientific developments and community needs, which has led to the launch of a new 10-year phase. SOLAS (2015-2025) will focus on five core science themes that will provide a scientific basis for understanding and projecting future environmental change and for developing tools to inform societal decision-making.
Published: 2015

49. Phosphate determination in seawater: Toward an autonomous electrochemical method

Author: Danièle Thouron, Violeta León Fernández, Justyna Jońca, Michelle Graco, Aurélien Paulmier, Véronique Garçon, DYNBIO LEGOS, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
Subjects: SILICATE, Sodium molybdate, Inorganic chemistry, Amperometry, Artificial seawater, Phosphate, 02 engineering and technology, Molybdate, Sensitivity and Specificity, 01 natural sciences, Phosphates, Analytical Chemistry, MEDIA, chemistry.chemical_compound, MICROELECTRODE PROCEDURES, Seawater, 14. Life underwater, ION, Molybdenum oxidation, Voltammetry, Detection limit, ELECTRODE, Chemistry, 010401 analytical chemistry, MOLYBDENUM, SENSOR, Electrochemical Techniques, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Electrochemical gas sensor, PHOSPHORUS, MEMBRANE, 0210 nano-technology, Oxidation-Reduction
Abstract: ISI Document Delivery No.: 867KE Times Cited: 8 Cited Reference Count: 25 Cited References: BEG MN, 1988, INDIAN J CHEM A, V27, P460 BOJINOV M, 1995, J ELECTROANAL CHEM, V381, P123, DOI 10.1016/0022-0728(94)03675-S Carpenter NG, 1997, ELECTROANAL, V9, P1311, DOI 10.1002/elan.1140091703 CONRATH N, 1995, ANAL CHIM ACTA, V309, P47, DOI 10.1016/0003-2670(95)00065-8 Cruywagen JJ, 2002, INORG CHIM ACTA, V331, P322, DOI 10.1016/S0020-1693(02)00700-4 Fernandez JJ, 1998, SENSOR ACTUAT B-CHEM, V47, P13, DOI 10.1016/S0925-4005(98)00003-3 FOGG AG, 1981, ANALYST, V106, P1288, DOI 10.1039/an9810601288 Gavalas VG, 2001, ANAL CHIM ACTA, V427, P271, DOI 10.1016/S0003-2670(00)01204-6 Gordon L.I., 1993, WOCE METHOD MANUAL, P68 Guanghan L, 1999, Talanta, V49, P511, DOI 10.1016/S0039-9140(99)00038-7 HARDEN SM, 1984, ANAL CHEM, V56, P2218, DOI 10.1021/ac00276a053 Hodgson AWE, 1998, ELECTROANAL, V10, P321, DOI 10.1002/(SICI)1521-4109(199804)10:53.3.CO;2-1 Krishnan CV, 2007, INT J ELECTROCHEM SC, V2, P29 Lacombe M, 2007, MAR CHEM, V106, P489, DOI 10.1016/j.marchem.2007.05.002 Lacombe M, 2008, TALANTA, V77, P744, DOI 10.1016/j.talanta.2008.07.023 Le Corre P., 1976, THESIS U BRETAGNE OC Liu D, 1997, ANAL CHIM ACTA, V338, P209, DOI 10.1016/S0003-2670(96)00382-0 LIU JH, 1990, J ELECTROANAL CHEM, V291, P67, DOI 10.1016/0022-0728(90)87178-M MATSUNAGA T, 1984, ENZYME MICROB TECH, V6, P355, DOI 10.1016/0141-0229(84)90048-6 Paytan A, 2007, CHEM REV, V107, P563, DOI 10.1021/cr0503613 Strickland J., 1972, PRACTICAL HDB SEAWAT, V167, P49 Truesdale W. V., 1976, ANALYST, V101, P19 Tyrrell T, 1999, NATURE, V400, P525, DOI 10.1038/22941 Wang K, 1998, ELECTROCHIM ACTA, V43, P2459 Zhang JZ, 1999, TALANTA, V49, P293, DOI 10.1016/S0039-9140(98)00377-4 Jonca, Justyna Leon Fernandez, Violeta Thouron, Daniele Paulmier, Aurelien Graco, Michelle Garcon, Veronique SENSEnet ITN (EC) [237868] We express our deep gratitude to Professor Maurice Comtat of Laboratoire de Genie Chimique, University Paul Sabatier, Toulouse, for his indispensable suggestions on the electrochemical part of this work. We are grateful to officers, scientists and crew of Pelagico 1011-12-BIC OLAYA cruise aboard R/V Jose Olaya Balandra for their assistance in the collection of samples; especially we would like to thank Miguel Sarmiento for his help during the water samples collection on board. Justyna Jonca is supported by a Marie Curie PhD grant within the SENSEnet ITN (EC Framework Programme 7, grant agreement No 237868). We warmly thank IRD and LMI DISCOH for help in logistics details and the staff of the laboratory of the Chemical Research Unit (UIOQ) at IMARPE for organisation of the cruise. 8 ELSEVIER SCIENCE BV AMSTERDAM TALANTA; Initial steps to create an autonomous in situ electrochemical sensor for orthophosphate determination in seawater are presented. First, the optimal conditions to form the molybdophosphate complex in artificial seawater medium were determined by addition of sulphuric acid and sodium molybdate to the solution containing orthophosphate. Secondly, the anodic oxidation of molybdenum to form molybdate ions and protons was used to create the molybdophosphate complex without addition of any liquid reagents. The molybdophosphate complex is detectable by amperometry with an average precision of 2.2% for the concentration range found in the open ocean and the detection limit is 0.12 mu M. Three solutions are proposed to address the silicate interferences issue and one of these methods is used for the natural samples collected in the coastal waters offshore Peru during the Pelagico 1011-12-BIC OLAYA cruise in November-December 2010. Results showed a good precision with an average of 2.5% and a reasonable deviation of the amperometric analysis as compared with colorimetric measurements (4.9%). (C) 2011 Elsevier B.V. All rights reserved.
Published: 2011

50. Use of SeaWiFS data for light availability and parameter estimation of a phytoplankton production model of the Bay of Biscay

Author: Daniel Delmas, Francis Gohin, Michel Lunven, Véronique Garçon, Martin Huret, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Chlorophyll, 0106 biological sciences, Chlorophyll a, Physical biogeochemical modelling, 010504 meteorology & atmospheric sciences, Forcing (mathematics), Aquatic Science, Oceanography, 01 natural sciences, chemistry.chemical_compound, SeaWiFS, Suspended Particulate Matter, Phytoplankton, Parameter estimation, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Estimation theory, 010604 marine biology & hydrobiology, Bay of Biscay, Plume, chemistry, 13. Climate action, Climatology, Environmental science, Bloom, Bay
Abstract: Processing SeaWiFS (Sea-viewing Wide Field-of-view Sensor) data provides useful information for the observation and modelling of the phytoplankton production of the Bay of Biscay. Empirical algorithms allow the retrieval of chlorophyll a and non-living Suspended Particulate Matter (SPM) concentrations. These data are used to constrain a coupled 3D physical–biogeochemical model of the Bay of Biscay continental shelf. Two issues are investigated, depending on the variable used, to constrain the winter to spring phytoplankton production for the year 2001. First, SPM data is used as forcing data to correct the corresponding state variable of our model. This allows the realistic simulation of the light limited bloom at the end of February 2001, as observed with SeaWiFS chlorophyll a images and from the NUTRIGAS field cruise. Second, chlorophyll a data is used for parameter estimation of the biogeochemical model. The ability of assimilating these data is tested to improve the simulation of strong blooms observed in late May 2001 in the Loire and Gironde plumes. A global optimization method (Evolutive Strategies) is adapted to the complete 3-D coupled model, in order to find the best set of parameters. The hydrological conditions during the bloom can be validated with data from the PEL01 field cruise. After selection of the most sensitive parameters, the method is tested with twin experiments. Then, the use of real SeaWiFS data reduces the model/data misfit by a factor of two, improving the simulation of bloom intensities and extensions. The sets of parameters retrieved in each plume are discussed.
Published: 2007

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