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1. Data quality control considerations in multivariate environmental monitoring: experience of the French coastal network SOMLIT

Author: Elsa Breton, Nicolas Savoye, Peggy Rimmelin-Maury, Benoit Sautour, Eric Goberville, Arnaud Lheureux, Thierry Cariou, Sophie Ferreira, Hélène Agogué, Samir Alliouane, Fabien Aubert, Sébastien Aubin, Eric Berthebaud, Hadrien Blayac, Lucie Blondel, Cédric Boulart, Yann Bozec, Sarah Bureau, Arnaud Caillo, Arnaud Cauvin, Jean-Baptiste Cazes, Léo Chasselin, Pascal Claquin, Pascal Conan, Marie-Ange Cordier, Laurence Costes, Romain Crec’hriou, Olivier Crispi, Muriel Crouvoisier, Valérie David, Yolanda Del Amo, Hortense De Lary, Gaspard Delebecq, Jeremy Devesa, Aurélien Domeau, Maria Durozier, Claire Emery, Eric Feunteun, Juliette Fauchot, Valérie Gentilhomme, Sandrine Geslin, Mélanie Giraud, Karine Grangeré, Gerald Grégori, Emilie Grossteffan, Aurore Gueux, Julien Guillaudeau, Gael Guillou, Manon Harrewyn, Orianne Jolly, Florence Jude-Lemeilleur, Paul Labatut, Nathalie Labourdette, Nicolas Lachaussée, Michel Lafont, Veronique Lagadec, Christophe Lambert, Jezebel Lamoureux, Laurent Lanceleur, Benoit Lebreton, Eric Lecuyer, David Lemeille, Yann Leredde, Cédric Leroux, Aude Leynaert, Stéphane L’Helguen, Camilla Liénart, Eric Macé, Eric Maria, Barbara Marie, Dominique Marie, Sébastien Mas, Fabrice Mendes, Line Mornet, Behzad Mostajir, Laure Mousseau, Antoine Nowaczyk, Sandra Nunige, René Parra, Thomas Paulin, David Pecqueur, Franck Petit, Philippe Pineau, Patrick Raimbault, Fabienne Rigaut-Jalabert, Christophe Salmeron, Ian Salter, Pierre-Guy Sauriau, Laurent Seuront, Emmanuelle Sultan, Rémi Valdès, Vincent Vantrepotte, Francesca Vidussi, Florian Voron, Renaud Vuillemin, Laurent. Zudaire, and Nicole Garcia
Subjects: environmental monitoring network, data quality control, inter-laboratory comparison exercises, measurement uncertainty, analyst performance, multivariate dataset, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: IntroductionWhile crucial to ensuring the production of accurate and high-quality data—and to avoid erroneous conclusions—data quality control (QC) in environmental monitoring datasets is still poorly documented.MethodsWith a focus on annual inter-laboratory comparison (ILC) exercises performed in the context of the French coastal monitoring SOMLIT network, we share here a pragmatic approach to QC, which allows the calculation of systematic and random errors, measurement uncertainty, and individual performance. After an overview of the different QC actions applied to fulfill requirements for quality and competence, we report equipment, accommodation, design of the ILC exercises, and statistical methodology specially adapted to small environmental networks (
Published: 2023
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2. Impact of an exceptional winter flood on benthic oxygen and nutrient fluxes in a temperate macrotidal estuary: Potential consequences on summer deoxygenation

Author: Vivien Hulot, Edouard Metzger, Aubin Thibault de Chanvalon, Aurelia Mouret, Sabine Schmidt, Bruno Deflandre, Sylvain Rigaud, Eric Beneteau, Nicolas Savoye, Philippe Souchu, Yoann Le Merrer, and Grégoire M. Maillet
Subjects: estuary, water sediment exchanges, hypoxia, oxides-phosphorus interactions, flood, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: Despite 20 years of control on eutrophication, episodes of summer hypoxia still occur in the Loire estuary, impacting water quality and posing a key scientific and management challenge. This work aimed to quantify the contribution of the benthic compartment to hypoxia in the Loire estuary by direct measurement of water–sediment fluxes and an in-depth understanding of the seasonal variations of oxides and phosphorus stocks. During the summer’s low-discharge period, results show that the iron oxide-rich deposit is stable under hypoxic conditions, limiting the release of dissolved phosphorus into the overlying water column. The high nitrate content of the water column appears to be an important oxidizer of iron during hypoxic periods, limiting dissolved phosphorus leakage and aggravation of hypoxia. During the exceptional winter flood, significant sediment erosion associated with bubbling phenomena (attributed to methane efflux) created severe fractures in the sediment and stimulated water–sediment exchange. During the following months, these fractures were progressively filled, which decreased the intensity of benthic fluxes. However, due to the high residence time in the water during the summer period, a simple model demonstrated that benthic contributions were sufficient to directly (by direct oxygen consumption) or indirectly (by promoting ammonia oxidation) affect the oxygen stock in the water column during the low-discharge period. Our study demonstrates the importance of the benthic compartment in the occurrence of hypoxia and the obvious lack of knowledge to illustrate and model the biogeochemical functioning of the estuary.
Published: 2023
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3. Coastal Ocean and Nearshore Observation: A French Case Study

Author: Lucie Cocquempot, Christophe Delacourt, Jérôme Paillet, Philippe Riou, Jérôme Aucan, Bruno Castelle, Guillaume Charria, Joachim Claudet, Pascal Conan, Laurent Coppola, Régis Hocdé, Serge Planes, Patrick Raimbault, Nicolas Savoye, Laurent Testut, and Renaud Vuillemin
Subjects: observation infrastructure, national structuration, interdisciplinary, coastal ocean, coastline, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: To understand and predict the physical, chemical, and biological processes at play in coastal and nearshore marine areas requires an integrated, interdisciplinary approach. The case study of the French structuration of coastal ocean and nearshore observing systems provides an original overview on a federative research infrastructure named ILICO. It is a notable example of national structuration and pan-institution efforts to investigate the forefront of knowledge on the processes at work within the critical coastal zone. ILICO comprises, in a pluridisciplinary approach, eight distributed network-systems of observation and data analysis that are accredited and financially supported by French research institutions and the French Ministry for Higher Education, Research, and Innovation. ILICO observation points are implemented along metropolitan and overseas French coasts, where coastline dynamics, sea level evolution, physical and biogeochemical water properties, coastal water dynamics, phytoplankton composition, and health of coral reefs are monitored in order to address a wide range of scientific questions. To give an overview of the diversity and potential of the observations carried out, this paper offers a detailed presentation of three constituting networks: Service Observation en Milieu LITtoral (SOMLIT), with homogeneous sampling strategies, DYNALIT, with heterogeneous sampling strategies adapted to different environments, and Mediterranean Ocean Observing System for the Environment (MOOSE), an integrated, pluri-disciplinary coastal/offshore regional observatory in the north-western Mediterranean Sea. ILICO was conceived using a European framework. It addresses the great challenges of the next decade in terms of sustainability, cost-efficiency, interoperability, and innovation. This paper emphasizes the added-value of federating these systems, and highlights some recommendations for the future.
Published: 2019
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4. Satellite and In Situ Monitoring of Chl-a, Turbidity, and Total Suspended Matter in Coastal Waters: Experience of the Year 2017 along the French Coasts

Author: Francis Gohin, Philippe Bryère, Alain Lefebvre, Pierre-Guy Sauriau, Nicolas Savoye, Vincent Vantrepotte, Yann Bozec, Thierry Cariou, Pascal Conan, Sylvain Coudray, Gaelle Courtay, Sylvaine Françoise, Anne Goffart, Tania Hernández Fariñas, Maud Lemoine, Aude Piraud, Patrick Raimbault, and Michael Rétho
Subjects: satellite, coastal monitoring, Chlorophyll-a, Total suspended matter, turbidity, Naval architecture. Shipbuilding. Marine engineering, VM1-989, Oceanography, GC1-1581
Abstract: The consistency of satellite and in situ time series of Chlorophyll-a (Chl-a), Turbidity and Total Suspended Matters (TSM) was investigated at 17 coastal stations throughout the year 2017. These stations covered different water types, from relatively clear waters in the Mediterranean Sea to moderately turbid regions in the Bay of Biscay and the southern bight of the North-Sea. Satellite retrievals were derived from MODIS/AQUA, VIIRS/NPP and OLCI-A/Sentinel-3 spectral reflectance. In situ data were obtained from the coastal phytoplankton networks SOMLIT (CNRS), REPHY (Ifremer) and associated networks. Satellite and in situ retrievals of the year 2017 were compared to the historical seasonal cycles and percentiles, 10 and 90, observed in situ. Regarding the sampling frequency in the Mediterranean Sea, a weekly in situ sampling allowed all major peaks in Chl-a caught from space to be recorded at sea, and, conversely, all in situ peaks were observed from space in a frequently cloud-free atmosphere. In waters of the Eastern English Channel, lower levels of Chl-a were observed, both in situ and from space, compared to the historical averages. However, despite a good overall agreement for low to moderate biomass, the satellite method, based on blue and green wavelengths, tends to provide elevated and variable Chl-a in a high biomass environment. Satellite-derived TSM and Turbidity were quite consistent with in situ measurements. Moreover, satellite retrievals of the water clarity parameters often showed a lower range of variability than their in situ counterparts did, being less scattered above and under the seasonal curves of percentiles 10 and 90.
Published: 2020
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5. Drivers of growth in a keystone fished species along the European Atlantic coast: The common cockle Cerastoderma edule

Author: M. Anouk Goedknegt, Nicolas Savoye, Sharon A. Lynch, Sarah C. Culloty, Kate E. Mahony, Hugues Blanchet, Shelagh K. Malham, Emily Groves, Sian Egerton, and Xavier de Montaudouin
Subjects: Abiotic component, Cerastoderma edule, Biotic component, Ecology, Fishing, Fisheries, Interspecific competition, Aquatic Science, Biology, Oceanography, biology.organism_classification, Spawn (biology), Salinity, von Bertalanffy growth model, Climate change, Cockle, Ecology, Evolution, Behavior and Systematics, Cockles, Stable isotopes, Shellfish
Abstract: A better understanding of growth drivers in shellfish populations including the common cockle Cerastoderma edule is essential, as their future is challenged by unsustainable fishing practices and climate change. In this study the spatial and temporal variabilities in common cockle growth across latitudes were assessed and compared with historical data. Six locations were examined at bimonthly intervals over 19 months; three Irish, two Welsh and one French, spanning the latitudes 54°N to 44°N. The results demonstrated that local abiotic and biotic factors have a larger impact on cockle growth than latitude. Cockles at similar latitudes grew at different rates and sizes, possibly due to factors such as density, fishing activity and interspecific competition. Cockles (0–3 years) impacted by low salinity and parasites (trematodes), exhibited reduced growth in later years. At the warmest, southernmost site growth was lowest in cockles >2 years. Previously, cockles at that site have been shown to spawn almost year-round, possibly diverting energy to gonad development rather than growth. The results opposed previously literature which demonstrated significantly greater growth at lower latitudes. These findings affirm that cockle growth and size is variable due to local abiotic (reduced salinity) and biotic (potentially trematode infection) drivers. Additionally, the synergistic relationship between these factors, i.e. warmer temperatures driving prolonged spawning, and the potential association between lower salinities and trematode prevalence, is concerning due to predicted climate related increases in temperature, precipitation and trematode prevalence/transmission, which may result in northern cockles reaching smaller maximum sizes.
Published: 2022

6. Trajectories of nutrients concentrations and ratios in the French coastal ecosystems: 20 years of changes in relation with large-scale and local drivers

Author: Arnaud Lheureux, Valérie David, Yolanda Del Amo, Dominique Soudant, Isabelle Auby, Yann Bozec, Pascal Conan, Florian Ganthy, Gérald Grégori, Alain Lefebvre, Aude Leynart, Peggy Rimmelin-Maury, Philippe Souchu, Vincent Vantrepote, Camille Blondel, Thierry Cariou, Olivier Crispi, Marie-Ange Cordier, Muriel Crouvoisier, Vincent Duquesne, Sophie Ferreira, Nicole Garcia, Laure Gouriou, Emilie Grosteffan, Yoann Le Merrer, Claire Meteigner, Michael Retho, Marie-Pierre Tournaire, and Nicolas Savoye
Subjects: Environmental Engineering, Climate Change, Humans, Environmental Chemistry, Human Activities, Nutrients, Pollution, Waste Management and Disposal, Ecosystem
Abstract: Along with their important diversity, coastal ecosystems receive various amounts of nutrients, principally arising from the continent and from the related human activities (mainly industrial and agricultural activities). During the 20th century, nutrients loads have increased following the increase of both the global population and need of services. Alongside, climate change including temperature increase or atmospheric circulation change has occurred. These processes, Ecosystem state changes are hard to monitor and predict. To study the long-term changes of nutrients concentrations in coastal ecosystems, eleven French coastal ecosystems were studied over 20 years as they encompass large climatic and land pressures, representative of temperate ecosystems, over a rather small geographical area. Both univariate (time series decomposition) and multivariate (relationships between ecosystems and drivers) statistical analyses were used to determine ecosystem trajectories as well as typologies of ecosystem trajectories. It appeared that most of the French coastal ecosystems exhibited trajectories towards a decrease in nutrients concentrations. Differences in trajectories mainly depended on continental and human influences, as well as on climatic regimes. One single ecosystem exhibited very different trajectories, the Arcachon Bay with an increase in nutrients concentrations. Ecosystem trajectories based on ordination techniques were proven to be useful tools to monitor ecosystem changes. This study highlighted the importance of local environments and the need to couple uni- and multi-ecosystem studies. Although the studied ecosystems were influenced by both local and large-scale climate, by anthropogenic activities loads, and that their trajectories were mostly similar based on their continental influence, non-negligible variations resulted from their internal functioning.
Published: 2023

7. Relationship between bacterial compartment and particulate organic matter (POM) in coastal systems: An assessment using fatty acids and stable isotopes

Author: Sophie Ferreira, Camilla Liénart, Laurence Costes, Pascal Conan, Tarik Meziane, Nicolas Savoye, Eric Maria, Sabrina Bichon, Karine Charlier, Cédric Hubas, Valérie David, Pierrick Barbier, Aurore Gueux, Hervé Derriennic, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Station de Biologie Marine de Concarneau, Direction générale déléguée à la Recherche, à l’Expertise, à la Valorisation et à l’Enseignement-Formation (DGD.REVE), Muséum national d'Histoire naturelle (MNHN)-Muséum national d'Histoire naturelle (MNHN), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Aquatic Science, Oceanography, French littoral, 01 natural sciences, Mixing models, Organic matter, 14. Life underwater, Fatty acids, POM dynamic, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, chemistry.chemical_classification, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Biomass (ecology), Primary producers, δ13C, Bacteria, 010604 marine biology & hydrobiology, δ15N, 15. Life on land, 6. Clean water, Food web, chemistry, 13. Climate action, Benthic zone, Environmental chemistry, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Surface water
Abstract: International audience; Particulate organic matter (POM) in coastal systems is a mixture of different organic matter (OM) sources originating from land and sea. Among sources, bacterial biomass plays a large role in OM processing and carbon recycling in the ocean and is often neglected as a source in common approaches. The present study proposes to use elemental and isotopic ratio of carbon and nitrogen (C:N, δ13C, δ15N) and fatty acids to investigate the relationship between bacteria and surface water POM composition of three systems with different characteristics (two marine and one estuarine) over an annual cycle. Overall, our results highlight a positive relationship between bacterial contribution and continental degraded or undergoing degradation POM for all the studied systems and an inverse relationship with pelagic primary producers. At multisystem scale, high bacterial contribution is linked to high proportion of refractory terrestrial material characterizing estuarine stations whereas in marine systems, the occurrence of bacteria is mainly linked to river POM. Over the annual cycle, bacterial markers are more abundant during the winter period characterized by larger river and/or benthic POM contribution. This seasonal pattern is mainly driven by changes in river flows and resuspension. This study highlights the importance of bacterial compartment as a component of coastal and estuarine POM. Even though these results remains semi-quantitative, similar studies in other types of systems can help to understand microbial role in OM dynamic and to better estimate bacterial source in carbon budgets and food web studies.
Published: 2020

8. Introduction générale

Author: Guy Bachelet, Marie-Laure Acolas, Magalie Baudrimont, Hugues Blanchet, Françoise Daverat, Frédéric Garabetian, Pierre Labadie, Alexia Legeay, Michel Leconte, Mario Lepage, Jérémy Lobry, Régine Maury-Brachet, Antoine Nowaczyk, Pierre-Guy Sauriau, Benoît Sautour, Hélène Budzinski, Aurélie Chaalali, Xavier Chevillot, Valérie David, Dominique Davoult, Yolanda del Amo, Aurélie Dessier, Marie-Hélène Devier, Eric Goberville, Benoît Gouillieux, Pierre-Yves Gourves, Philippe Jatteau, Mathilde Lauzent, Gabriel Munoz, Aimé Roger Nzigou, Stéphanie Pasquaud, Fabien Pierron, Julien Richirt, Eric Rochard, Nicolas Savoye, and Nathalie Tapie
Published: 2020

9. Les effets des pressions anthropiques sur la biodiversité

Author: Guy Bachelet, Marie-Laure Acolas, Magalie Baudrimont, Hugues Blanchet, Françoise Daverat, Frédéric Garabetian, Pierre Labadie, Alexia Legeay, Michel Leconte, Mario Lepage, Jérémy Lobry, Régine Maury-Brachet, Antoine Nowaczyk, Pierre-Guy Sauriau, Benoît Sautour, Hélène Budzinski, Aurélie Chaalali, Xavier Chevillot, Valérie David, Dominique Davoult, Yolanda del Amo, Aurélie Dessier, Marie-Hélène Devier, Eric Goberville, Benoît Gouillieux, Pierre-Yves Gourves, Philippe Jatteau, Mathilde Lauzent, Gabriel Munoz, Aimé Roger Nzigou, Stéphanie Pasquaud, Fabien Pierron, Julien Richirt, Eric Rochard, Nicolas Savoye, and Nathalie Tapie
Published: 2020

10. Les évolutions récentes de la biodiversité

Author: Guy Bachelet, Marie-Laure Acolas, Magalie Baudrimont, Hugues Blanchet, Françoise Daverat, Frédéric Garabetian, Pierre Labadie, Alexia Legeay, Michel Leconte, Mario Lepage, Jérémy Lobry, Régine Maury-Brachet, Antoine Nowaczyk, Pierre-Guy Sauriau, Benoît Sautour, Hélène Budzinski, Aurélie Chaalali, Xavier Chevillot, Valérie David, Dominique Davoult, Yolanda del Amo, Aurélie Dessier, Marie-Hélène Devier, Eric Goberville, Benoît Gouillieux, Pierre-Yves Gourves, Philippe Jatteau, Mathilde Lauzent, Gabriel Munoz, Aimé Roger Nzigou, Stéphanie Pasquaud, Fabien Pierron, Julien Richirt, Eric Rochard, Nicolas Savoye, and Nathalie Tapie
Published: 2020

11. Les compartiments biologiques et leurs interrelations

Author: Marie-Laure Acolas, Guy Bachelet, Magalie Baudrimont, Hugues Blanchet, Françoise Daverat, Frédéric Garabetian, Pierre Labadie, Alexia Legeay, Michel Leconte, Mario Lepage, Jérémy Lobry, Régine Maury-Brachet, Antoine Nowaczyk, Pierre-Guy Sauriau, Benoît Sautour, Hélène Budzinski, Aurélie Chaalali, Xavier Chevillot, Valérie David, Dominique Davoult, Yolanda del Amo, Aurélie Dessier, Marie-Hélène Devier, Eric Goberville, Benoît Gouillieux, Pierre-Yves Gourves, Philippe Jatteau, Mathilde Lauzent, Gabriel Munoz, Aimé Roger Nzigou, Stéphanie Pasquaud, Fabien Pierron, Julien Richirt, Eric Rochard, Nicolas Savoye, and Nathalie Tapie
Published: 2020

12. Spatial and temporal distribution of mercury and methylmercury in bivalves from the French coastline

Author: Nicolas Briant, Christophe Brach-Papa, Nicolas Savoye, Jeroen E. Sonke, Jean-Francois Chiffoleau, Joël Knoery, Laura Martinez, and Tiphaine Chouvelon
Subjects: Bivalves, animal structures, 010504 meteorology & atmospheric sciences, Speciation, chemistry.chemical_element, 010501 environmental sciences, Aquatic Science, Oceanography, 01 natural sciences, chemistry.chemical_compound, Spatio-Temporal Analysis, Animals, 14. Life underwater, Methylmercury, 0105 earth and related environmental sciences, Mytilus, biology, fungi, Isognomon alatus, Mercury, Methylmercury Compounds, biology.organism_classification, Pollution, Mercury (element), Fishery, chemistry, Crassostrea, France, Water Pollutants, Chemical, Environmental Monitoring
Abstract: Marine mercury (Hg) concentrations have been monitored in the French coastline for the last half a century using bivalves. The analyses presented in this study concerned 192 samples of bivalves (mussels: Mytilus edulis and Mytilus galloprovincialis and oysters: Crassostrea gigas and Isognomon alatus) from 77 sampling stations along the French coast and in the French Antilles sea. The goals of this study were to assess MeHg levels in various common bivalves from French coastline, and to identify possible geographic, taxonomic or temporal variations of concentrations. We show that the evolution of methylmercury (MeHg) concentrations covary with total mercury (HgT) concentrations. Moreover, in most of the study sites, HgT concentrations have not decreased since 1987, despite regulations to decrease or ban mercury used for anthropic activities.
Published: 2017

13. Seasonal and long-term changes in elemental concentrations and ratios of marine particulate organic matter

Author: Adam C. Martiny, Yann Bozec, Nicolas Savoye, Michael W. Lomas, Agathe Talarmin, Helene Frigstad, and David M. Karl
Subjects: 0106 biological sciences, Atmospheric Science, Global and Planetary Change, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Phosphorus, chemistry.chemical_element, Pelagic zone, Estuary, Particulates, 01 natural sciences, Nutrient, Oceanography, chemistry, Ecological stoichiometry, Environmental Chemistry, Environmental science, Ecosystem, 0105 earth and related environmental sciences, General Environmental Science, Redfield ratio
Abstract: What is the temporal variability of the elemental stoichiometry of marine microbial communities across ocean regions? To answer this question, we present an analysis of environmental conditions, particulate organic carbon, nitrogen, and phosphorus concentrations and their ratios across 20 time series (3–25 years duration) representing estuarine, coastal, and open ocean environments. The majority of stations showed significant seasonal oscillations in particulate organic elemental concentrations and ratios. However, shorter-term changes contributed most to overall variance in particulate organic matter concentrations and ratios. We found a correlation between the seasonal oscillations of environmental conditions and elemental ratios at many coastal but not open ocean and estuarine stations. C:N peaked near the seasonal temperature minimum and nutrient maximum, but some stations showed other seasonal links. C:N ratios declined with time over the respective observation periods at all open ocean and estuarine stations as well as at five coastal station but increased at the nine other coastal stations. C:P (but not N:P) declined slightly at Bermuda Atlantic Time-series Study but showed large significant increases at Hawaii Ocean Time-series and Arendal stations. The relationships between long-term changes in environmental conditions and particulate organic matter concentrations or ratios were ambiguous, but interactions between changes in temperature and nutrient availability were important. Overall, our analysis demonstrates significant changes in elemental ratios at long-term and seasonal time scales across regions, but the underlying mechanisms are currently unclear. Thus, we need to better understand the detailed mechanisms driving the elemental composition of marine microbial ecosystems in order to predict how oceans will respond to environmental changes.
Published: 2016

14. Dynamics of microbial communities across the three domains of life over an annual cycle with emphasis on marine mucilage in the Southern Bay of Biscay resolved by microbial fingerprinting

Author: Yolanda Del Amo, Anne Fahy, Nicolas Susperregui, Robert Duran, Rémy Guyoneaud, Nicolas Savoye, Sabrina Bichon, Philippe Gaudin, Vanessa Rouaud, Béatrice Lauga, Camilla Liénart, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Milieux Aquatiques, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA), Aquitaine Regional Government Council, the Agence de l’Eau Adour-Garonne, France Filière Pêche to the PERMALA-LIGA program, Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux (IPREM), Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Muséum National d'Histoire Naturelle (MNHN)-Université de Caen Normandie (UNICAEN), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit [Brussels] (VUB), Groupe de Recherche et d'Etudes du Processus Inflammatoire (GREPI), and Université Joseph Fourier - Grenoble 1 (UJF)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Mucilage, [SDE.MCG]Environmental Sciences/Global Changes, Context (language use), Aquatic Science, Oceanography, 01 natural sciences, T-RFLP fingerprinting, Littoral zone, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, River, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Geology, Estuary, Pelagic zone, Microbial community structure, Coastal seawater, Annual cycle, Geography, Microbial population biology, 13. Climate action, Littoral, [SDE]Environmental Sciences, Bay
Abstract: International audience; Marine mucilage has been described as worldwide phenomena occurring sporadically, or frequently in certain coastal areas. They are transitory phenomena that can remain in the photic zone for several days or weeks. Their occurrence has been more frequent and persistent, and their magnitude has increased during the last decades. Their formation typically reflects an imbalance in the marine microbial communities, and has frequently be linked to global changes. Recurrent marine mucilage events have been observed in recent years in the Southern Bay of Biscay near the French coast, mainly south of the Adour estuary. In this study, we used a fingerprinting method (T-RFLP) targeting 16S and 18S rRNA genes to investigate marine microbial community composition and dynamics over an annual cycle across the three domains of life in coastal water at three depths, in the Adour River upstream of the mouth and in the marine mucilage. In line with studies conducted in marine environments we highlighted that the dynamics of marine microbial communities in the Bay of Biscay coincided with two environmental contexts: winter and spring on one hand and summer and autumn on the other hand. More interestingly, this dynamics affects also the marine pelagic mucilage that was observed during the sampling campaigns. Thus, the composition of the marine mucilage that appears in winter/spring context diverges from the composition of the marine mucilage that occurred during the summer/autumn context. We highlighted also that marine microbial communities were partly different from marine mucilage communities with an enrichment of some microorganisms suggesting that marine mucilage behaves as a microhabitat in seawater and possesses distinct microbial assemblages from the surrounding communities.
Published: 2019

15. Dynamics of particulate organic matter in a coastal system characterized by the occurrence of marine mucilage – A stable isotope study

Author: Béatrice Lauga, Karine Charlier, Robert Duran, Joana Cavalheiro, Sabrina Bichon, Vanessa Rouaud, Thierry Pigot, Valérie David, Mathilde Monperrus, Camilla Liénart, Yolanda Del Amo, Nicolas Savoye, Nicolas Susperregui, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-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 Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Pau et des Pays de l'Adour (UPPA), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), PERMALA-LIGA (Aquitaine Regional Council), EC2CO-DRIL MOSLIT (French national program), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), and Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Marine mucilage, Aquatic Science, Oceanography, 01 natural sciences, Water column, Particulate organic matter, Phytoplankton, [CHIM]Chemical Sciences, Coastal systems, Organic matter, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Stable isotopes, 0105 earth and related environmental sciences, chemistry.chemical_classification, 010604 marine biology & hydrobiology, Sediment, 15. Life on land, Bay of Biscay, Annual cycle, Deposition (aerosol physics), chemistry, Mucilage, 13. Climate action, Environmental science, Bay
Abstract: International audience; In coastal systems, particulate organic matter (POM) originates from various autochthonous and allochthonous organic matter sources. Also, some coastal systems are characterized by the occurrence of large amounts of mucilaginous material of biologic origin (i.e. phytoplankton, bacteria), which aggregates and potentially traps other organisms and particles present in the water column. This study focuses on POM origin and spatio-temporal dynamics in the South-East coast of the Bay of Biscay, an area subject to mucilage occurrence. In order to investigate POM quantitative and qualitative (C and N elemental and isotopic ratios) characteristics, sampling was performed over an annual cycle at two sites experiencing different mucilage occurrence and river influence. Contribution of phytoplankton, terrestrial POM and anthropogenic POM to coastal-POM composition was calculated using a three-sources mixing model. Overall, phytoplankton dominated the coastal-POM composition at all seasons, sites and most of the depths (71.6 ± 24.2%). Terrestrial-POM contribution was moderate (22.7 ± 21.8%) and anthropogenic-POM contribution was usually negligible (5.7 ± 7.4%). Both sites mainly exhibited similar vertical and temporal variations in terms of POM origin and dynamics: terrestrial-POM contribution increased with depth and was higher in winter at all depths and in autumn in bottom waters, compared to other seasons. The main differences between both sites were related to the vertical dynamics of the terrestrial contribution to the coastal POM. Horizontal, vertical and temporal variation of POM composition was linked to processes driving the sedimentary hydrodynamics: the river flow, the direction of the river plume and events of sediment resuspension/deposition. During the study period, the mucilage occurred only as flocs (small aggregates). The mucilage was of autochthonous origin and did not trap detectable amount of allochthonous material. © 2016 Elsevier B.V.
Published: 2016

16. Estuarine habitats structure zooplankton communities: Implications for the pelagic trophic pathways

Author: Benoit Gouillieux, Nicolas Savoye, Guy Bachelet, Hugues Blanchet, Jonathan Selleslagh, Benoît Sautour, Valérie David, Michel Leconte, Sophie Dubois, Jérémy Lobry, Nicolas Lavesque, Antoine Nowaczyk, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes aquatiques et changements globaux (UR EABX), and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
Subjects: 0106 biological sciences, geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Intertidal zone, Pelagic zone, Estuary, Aquatic Science, Oceanography, 010603 evolutionary biology, 01 natural sciences, Zooplankton, Food web, Fishery, Habitat, [SDE]Environmental Sciences, Environmental science, 14. Life underwater, Trophic level, Isotope analysis
Abstract: International audience; Estuarine ecosystems have been described as a mosaic of habitats exhibiting different physical, biological and chemical properties and processes. These habitats are of primary importance for fishes, providing refuges and/or food for juveniles. While it is well known that habitats contribute also to the structuration of meio- and macrobenthic assemblages, this concept of habitat has never been associated to zooplankton communities, a major food resource for many pelagic fishes during summer in North-European estuaries. The objective of this work was thus to assess if estuarine habitats, in addition to the salinity gradient, structured zooplankton communities as well. Sampling was conducted at high tide during summer in a highly turbid system, the Gironde estuary, for which primary production and thus food resource at the basis of the food web is strongly limited. The results showed that even if the upstream-downstream estuarine gradient was the main factor structuring zooplankton at the scale of the estuary, there was a significant difference of zooplankton assemblages between samples collected over subtidal areas and those collected over intertidal areas. More particularly, the estuarine gradient was associated to the distribution pattern of species while difference between subtidal and intertidal samples were mainly due to difference in the level of abundance of species. Stable isotope analysis revealed that these zooplanktonic omnivorous species may be attracted to intertidal mudflats by microphytobenthos availability and that some planktivorous fishes, in particular Alosa fallax, preferentially fed on this zone. The role of intertidal habitats in structuring zooplankton assemblages suggests that this habitat strongly participates to the production of planktivorous species and that it represents a biotic vector of carbon resources toward subtidal areas. The loss of tidal flats habitats could thus have consequences on the functioning of pelagic system as well.
Published: 2016

17. Precise indices based on n-alkane distribution for quantifying sources of sedimentary organic matter in coastal systems

Author: Nicolas Savoye, Sophie Dubois, Nicolas R. Chevalier, Valérie David, Hélène Budzinski, Karyn Le Menach, Mathias Lama Lama, Pascal Lecroart, and Laboratoire d’Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), UMR CNRS 5805, Allée Geoffroy Saint-Hilaire, 33615 Pessac Cedex, France
Subjects: Spartina, 010504 meteorology & atmospheric sciences, biology, Terrigenous sediment, Coastal system, Arcachon Bay, 010502 geochemistry & geophysics, biology.organism_classification, 01 natural sciences, n-Alkanes, Seagrass, Oceanography, Algae, 13. Climate action, Geochemistry and Petrology, Aquatic plant, [SDE]Environmental Sciences, Sedimentary organic matter, [CHIM]Chemical Sciences, Environmental science, 14. Life underwater, Zostera, Bay, 0105 earth and related environmental sciences
Abstract: International audience; Precise indices based on n-alkane signatures were developed in order to determine the sources and composition of sedimentary organic matter (SOM) in coastal systems. The Arcachon Bay (France), a well-studied temperate lagoon, was used as an example of a complex coastal system sheltering a wide diversity of OM sources. Three main groups of sources were well discriminated from their n-alkane signatures: seagrass (Zostera sp.) produced mainly n-C17, n-C19, n-C21, n-C23 and n-C25 alkanes, algae (Rhodophyta, Chlorophyta) produced n-C15 and n-C17 and the terrigenous input [Quercus sp., Spartina sp. and river suspended particulate OM (SPOM)] was characterized by n-C25, n-C27, n-C29, n-C31 and n-C33. From the above and literature n-alkane fingerprints, we developed a set of indices (n-alkane ratios) to quantify the contribution of these three major sources of the SOM. At the Arcachon Bay scale, they indicated that SOM was composed mainly of seagrass (ca. 53 ± 19%) and terrestrial (ca. 41 ± 17%) material, followed by algae (ca. 6 ± 9%). Moreover, the new n-alkane indices exhibited more relevant spatial patterns than classical ones – the TAR (C27 + C29 + C31/C15 + C17 + C19; terrestrial to aquatic ratio) and the Paq (C23 + C25/C23 + C25 + C29 + C31; aquatic plant %) – with a greater contribution from marine sources in the central part of the lagoon where a high density of Zostera seagrass was observed. Therefore, the development of precise indices adapted to the local diversity of OM sources is needed when using n-alkanes for quantifying the source composition of SOM in complex coastal systems.
Published: 2015

18. Impact of human activities on the spatio-seasonal dynamics of plankton diversity in drained marshes and consequences on eutrophication

Author: Olivier Philippine, Martine Bréret, Valérie David, François-Xavier Robin, Christine Dupuy, Sébastien Tortajada, Nicolas Lachaussée, Nicolas Savoye, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and Union des marais de la Charente-Maritime (UNIMA)
Subjects: Environmental Engineering, Marsh, 0208 environmental biotechnology, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Zooplankton, Phytoplankton, Dominance (ecology), Animals, Humans, Human Activities, 14. Life underwater, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, geography, geography.geographical_feature_category, Ecology, Ecological Modeling, Hypoxia (environmental), Pelagic zone, 15. Life on land, Plankton, Eutrophication, Pollution, 6. Clean water, 020801 environmental engineering, 13. Climate action, Wetlands, [SDE]Environmental Sciences, Environmental science, Seasons, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: The functional diversity of two planktonic functional compartments, the nano-microphytoplankton and the mesozooplankton was used in order to better understand i) the drained marshes functioning and their related ecological functions, ii) the impacts of human control (replenishment) and human activities on the catchment basin (urbanization and catchment basin size). It was based on a monthly seasonal survey on 7 freshwater drained marshes. Both nano-microphyto- and mesozooplankton displayed high seasonal variations linked to the environmental fluctuations and human control on sea lock gates. Winter presented the lower biomasses of both compartments. Winter that is characterized by low water temperature, low light availability and high flood is actually related to the dominance of tychopelagic phytoplankton and K-strategists zooplankton. Spring and summer were characterized by i) the succession of pelagic large cells, small cells and then taxa with alternatives food strategies due to nitrogen limitation and phosphorous desorption from the sediment leading to eutrophication processes and ii) the dominance of r-strategists for mesozooplankton. The artificial summer replenishment acts positively on water quality by decreasing the eutrophication processes since the nitrogen inputs limit the proliferation of phytoplankton mixotrophs and diazotrophs and increase the ecological efficiency during the warm period. Both small and large catchment basins may lead to summer eutrophication processes in drained marshes since the largest ones imply higher hydrodynamic features at the root of large inputs of nitrogen nutrient favoring the phytoplankton development while the smallest ones exhibit hypoxia problems due to high proliferation of macrophytes. Urbanized marshes are less subjected to eutrophication during summer than non urbanized marshes due to more recurrent nutrient inputs from urban waste. However they exhibited a lower ecological efficiency. The results suggest that a better management of the hydrodynamics of such anthropogenic systems can avoid eutrophication risks on coastal areas.
Published: 2018

19. Liga en Sud-Aquitaine. Causes et conséquences du développement de 'neige marine' sur la côte Basque et le sud des Landes

Author: Nicolas Susperregui, Philippe Gaudin, Béatrice Lauga, Robert Duran, Vanessa Rouaud, Mathilde Monperrus, Thierry Pigot, Denis Morichon, Gaëlle Deletraz, Yolanda Del Amo, Nicolas Savoye, Camilla Liénart, Florence Jude, Valerie David, Edith PARLANTI, Jeremie Parot, Mahaut Sourzac, Marie-Ange Cordier, Elbée, Jean D., Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA), Passages, Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Pau et des Pays de l'Adour (UPPA)-Ministère de la Culture et de la Communication (MCC)-Université de Bordeaux (UB), Agence de l'Eau Adour Garonne, France Filière Pêche, Région Nouvelle-Aquitaine, Fédération MIRA - Milieux et Ressources Aquatiques, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Pau et des Pays de l'Adour (UPPA), and Université de Bordeaux (UB)-Ministère de la Culture et de la Communication (MCC)-Université de Pau et des Pays de l'Adour (UPPA)-Université Bordeaux Montaigne-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDV]Life Sciences [q-bio], [CHIM]Chemical Sciences, [SHS.GEO]Humanities and Social Sciences/Geography
Published: 2018

20. Dynamics of particulate organic matter composition in coastal systems: Forcing of spatio-temporal variability at multi-systems scale

Author: Philippe Pineau, Aurore Gueux, Martine Bréret, Sophie Ferreira, Muriel Crouvoisier, Cédric Leroux, Pascal Claquin, Francois Dindinaud, Peggy Rimmelin-Maury, Camilla Liénart, Elsa Breton, Gaël Guillou, Pascal Conan, Mireille Pujo-Pay, Patrick Raimbault, Franck Petit, Béatrice Lauga, Emilie Grossteffan, Nicolas Susperregui, Michel Lafont, Paco Rodriguez Tress, Véronique Lagadec, Emmanuelle Sultan, Eric Maria, Pierre-Guy Sauriau, Yann Bozec, Julien Guillaudeau, Jézabel Lamoureux, Sandrine Geslin, Fabien Aubert, Orianne Jolly, Anne-Marie Corre, Nicolas Savoye, Maïa Durozier, Laurence Costes, Eric Feunteun, Sabrina Bichon, Stéphane L'Helguen, Eric Macé, Benoit Lebreton, Nicolas Lachaussée, Christophe Boinet, Valérie David, Vincent Marieu, Laure Mousseau, Jocelyne Caparros, Hervé Derriennic, Yolanda Del Amo, Vanessa Rouaud, Jean-Paul Lehodey, Sébastien Aubin, Robert Duran, Thierry Cariou, Nicole Garcia, Line Bourasseau, Pierre Ramond, Vincent Hanquiez, Eric Lecuyer, Jérémy Devesa, Antoine Nowaczyk, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Environnements et Paléoenvironnements OCéaniques (EPOC), Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Station marine Dinard, Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), CHImie Marine (CHIM), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), 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), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Nutrition et Neurobiologie intégrée (NutriNeuro), Université Bordeaux Segalen - Bordeaux 2-Institut National de la Recherche Agronomique (INRA)-Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Ecole nationale supérieure de chimie, biologie et physique, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Centre de recherches en environnement côtier (CREC), Université de Caen Normandie (UNICAEN), Institut des Milieux Aquatiques, PERMALA-LIGA, funded by the Aquitaine Regional Council, EC2CO-DRIL MOSLIT, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), 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]), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche de Roscoff (FR2424), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Université Bordeaux Segalen - Bordeaux 2-Institut National de la Recherche Agronomique (INRA)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut Polytechnique de Bordeaux-Ecole nationale supérieure de chimie, biologie et physique, 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 Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit [Brussels] (VUB), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Nutrition et Neurobiologie intégrée (NutriNeur0), Ecole nationale supérieure de chimie, biologie et physique-Institut Polytechnique de Bordeaux-Université Sciences et Technologies - Bordeaux 1-Institut National de la Recherche Agronomique (INRA)-Université Bordeaux Segalen - Bordeaux 2, Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Evolution des Systèmes Naturels et Modifiés (LESNM), Muséum national d'Histoire naturelle (MNHN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre de recherche et d'enseignement des systèmes côtiers (CRESCO), Muséum national d'Histoire naturelle (MNHN), UMS 3113, Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO), Qualité des eaux et prévention des pollutions (UR QELY), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Station Marine, Université de Lille, Sciences et Technologies-PRES Université Lille Nord de France-Centre National de la Recherche Scientifique (CNRS), Sorbonne Universités, Centre d'Analyse et d'Intervention Sociologiques (CADIS), École des hautes études en sciences sociales (EHESS)-Centre National de la Recherche Scientifique (CNRS), EMBIO, Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Laboratoire Biens, Normes, Contrats (LBNC), Avignon Université (AU), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Pau et des Pays de l'Adour (UPPA), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Pau et des Pays de l'Adour (UPPA), and 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)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Environmental forcing, Forcing (mathematics), Aquatic Science, 01 natural sciences, Water column, Particulate organic matter, Phytoplankton, medicine, Coastal systems, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Trophic level, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, ACL, Geology, Estuary, Seasonality, medicine.disease, Meta-analysis, Oceanography, 13. Climate action, Benthic zone, [SDE]Environmental Sciences, Environmental science, Sedimentary rock, France, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; In costal systems, particulate organic matter (POM) results from a multiplicity of sources having their respective dynamics in terms of production, decomposition, transport and burial. The POM pool experiences thus considerable spatial and temporal variability. In order to better understand this variability, the present study employs statistical multivariate analyses to investigate links between POM composition and environmental forcings for a panel of twelve coastal systems distributed along the three maritime regions of France and monitored weekly to monthly for 1 to 8 years.At multi-system scale, two main gradients of POC composition have been identified: a 'Continent-Ocean' gradient associated with hydrodynamics, sedimentary dynamics and depth of the water column, and a gradient of trophic status related to nutrient availability. At local scale, seasonality of POC composition appears to be station-specific but still related to part of the above-mentioned forcings. A typology of systems was established by coupling spatial and temporal variability of POC composition. Four groups were highlighted: (1) the estuarine stations where POC composition is dominated by terrestrial POM and driven by hydrodynamics and sedimentary processes, (2) the oligotrophic systems, characterized by the contribution of diazotrophs due to low nutrient availability, and the marine meso/eutroph systems whose POC composition is (3) either deeply dominated by phytoplankton or (4) dominated by phytoplankton but where the contribution of continental and benthic POC is not negligible and is driven by hydrodynamics, sedimentary processes and the height of the water column.Finally, the present study provides several insights into the different forcings to POM composition and dynamics in temperate coastal systems at local and multi-system scales. This work also presents a methodological approach that establishes statistical links between forcings and POM composition, helping to gain more objectively insight of forcings.
Published: 2018

21. Dynamics of particulate organic matter composition in coastal systems: a spatio-temporal study at multi-systems scale

Author: Francois Dindinaud, Michel Lafont, Aurore Gueux, Benoit Lebreton, Christophe Boinet, Vincent Cornille, Gaël Guillou, Jocelyne Caparros, Martine Bréret, Jean-Paul Lehodey, Julien Guillaudeau, Pierre Richard, Fabien Aubert, Sabrina Bichon, Stéphane L'Helguen, Fabrice Garcia, Eric Maria, Laurence Costes, Yolanda Del Amo, Eric Macé, Nicolas Lachaussée, Sandrine Geslin, Pascal Riera, Gauthier Schaal, Elsa Breton, Emilie Grossteffan, Valérie David, Laure Mousseau, Emmanuelle Sultan, Pierre-Guy Sauriau, Karine Grangeré, Nicolas Savoye, Maïa Durozier, Nicole Garcia, Line Bourasseau, Eric Lecuyer, Olivier Crispi, Pascal Claquin, Michel Fornier, David Lemeille, Yann Bozec, Philippe Kerhervé, Franck Petit, Mireille Pujo-Pay, Cédric Leroux, Anne-Marie Corre, Marie Czamanski, Antoine Nowaczyk, Jérémy Devesa, Karine Charlier, Jézabel Lamoureux, Orianne Joly, Hervé Derriennic, Sébastien Aubin, Thierry Cariou, Peggy Rimelin-Maury, Vincent Hanquiez, Sébastien Lefebvre, Camilla Liénart, Patrick Raimbault, Eric Feunteun, Philippe Pineau, Sophie Ferreira, Muriel Crouvoisier, Pascal Conan, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), CHImie Marine (CHIM), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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]), Université du Littoral Côte d'Opale (ULCO), Laboratoire d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Station marine Dinard, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), 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 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), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), 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), Ecogéochimie et Fonctionnement des Ecosystèmes Benthiques (EFEB), Muséum national d'Histoire naturelle (MNHN), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche de Roscoff (FR2424), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de recherches en environnement côtier (CREC), Normandie Université (NU)-Normandie Université (NU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Adaptation et diversité en milieu marin (AD2M), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-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)-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), 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), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Centre de recherche et d'enseignement des systèmes côtiers (CRESCO), Harte Research Institute for Gulf of Mexico Studies, Texas A&M University [Corpus Christi], Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), ESEO-GSII (GSII), ESEO-Tech, Université Bretagne Loire (UBL)-Université Bretagne Loire (UBL), CNRS 5320, Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Nutrition et Neurobiologie intégrée (NutriNeur0), Ecole nationale supérieure de chimie, biologie et physique-Institut Polytechnique de Bordeaux-Université Sciences et Technologies - Bordeaux 1-Institut National de la Recherche Agronomique (INRA)-Université Bordeaux Segalen - Bordeaux 2, Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG), Institut de Physique du Globe de Paris, Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Brest (UBO), EMBIO, Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), UMS 3113, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO), Biologie des écosystèmes aquatiques (UR BELY), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Normandie Université (NU), Centre Émile Durkheim (CED), 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), 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)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Biologie des Organismes et Ecosystèmes Aquatiques ( BOREA ), Université des Antilles ( UA ) -Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Institut de Recherche pour le Développement ( IRD ) -Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Environnements et Paléoenvironnements OCéaniques ( EPOC ), Observatoire aquitain des sciences de l'univers ( OASU ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -École pratique des hautes études ( EPHE ) -Centre National de la Recherche Scientifique ( CNRS ), CHImie Marine ( CHIM ), Adaptation et diversité en milieu marin ( ADMM ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 ( LOG ), Université du Littoral Côte d'Opale-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Océanographie Microbienne ( LOMIC ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), LIttoral ENvironnement et Sociétés - UMR 7266 ( LIENSs ), Université de La Rochelle ( ULR ) -Centre National de la Recherche Scientifique ( CNRS ), Centre de recherche et d'enseignement des systèmes côtiers ( CRESCO ), Muséum National d'Histoire Naturelle ( MNHN ), Centre de Formation et de Recherche sur les Environnements Méditérranéens ( CEFREM ), Université de Perpignan Via Domitia ( UPVD ) -Centre National de la Recherche Scientifique ( CNRS ), Harte Research Institute for Gulf of Mexico Studies, Texas A&M University – Corpus Christi, Rongeurs Sauvages – Risques Sanitaires et Gestion des Populations, INRA, VetAgro Sup ( USC1233/RS2GP ), Institut National de la Recherche Agronomique ( INRA ) -VetAgro Sup ( VAS ), Laboratoire des Sciences de l'Environnement Marin (LEMAR) ( LEMAR ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Brest ( UBO ) -Institut Français de Recherche pour l'Exploitation de la Mer ( IFREMER ) -Institut Universitaire Européen de la Mer ( IUEM ), Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ), Laboratoire d'océanographie de Villefranche ( LOV ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Institut méditerranéen d'océanologie ( MIO ), Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Université de Toulon ( UTLN ) -Centre National de la Recherche Scientifique ( CNRS ), Ecogéochimie et Fonctionnement des Ecosystèmes Benthiques ( EFEB ), ESEO-GSII ( GSII ), PRES Université Nantes Angers Le Mans ( UNAM ) -PRES Université Nantes Angers Le Mans ( UNAM ), Centre de recherche Paul Pascal, CNRS, Université de Bordeaux ( UPR8641 ), Centre de Recherche Paul Pascal, CNRS, Université de Bordeaux, Centre National de la Recherche Scientifique ( CNRS ), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux ( EPOC ), Station biologique de Roscoff [Roscoff] ( SBR ), Nutrition et Neurobiologie intégrée ( NutriNeur0 ), Université Bordeaux Segalen - Bordeaux 2-Institut National de la Recherche Agronomique ( INRA ) -Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Ecole nationale supérieure de chimie, biologie et physique, OVSG-IPGP, Observatoire Volcanologique et sismologique de la Soufrière de Guadeloupe, Institut de Biologie Intégrative de la Cellule ( I2BC ), Université Paris-Sud - Paris 11 ( UP11 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Université de Brest ( UBO ), Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Université de Toulon ( UTLN ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Université de Toulon ( UTLN ) -Centre National de la Recherche Scientifique ( CNRS ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Universitaire Européen de la Mer ( IUEM ), Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ), Centre de recherches en environnement côtier ( CREC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ), Biologie des écosystèmes aquatiques ( UR BELY ), CEMAGREF, Normandie Université ( NU ), Centre Émile Durkheim ( CED ), and Université de Bordeaux ( UB ) -Sciences Po-Centre National de la Recherche Scientifique ( CNRS )
Subjects: 0106 biological sciences, Mediterranean climate, 010504 meteorology & atmospheric sciences, chibido, Mixing model, Aquatic Science, 01 natural sciences, coastal systems, N ratio [C], C:N ratio, Water column, Particulate organic matter, Phytoplankton, Littoral zone, medicine, Coastal systems, Organic matter, 14. Life underwater, particulate organic matter, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, chemistry.chemical_classification, [ SDE.BE ] Environmental Sciences/Biodiversity and Ecology, geography, geography.geographical_feature_category, C and N stable isotopes, 010604 marine biology & hydrobiology, ACL, Geology, Estuary, Seasonality, mixing model, medicine.disease, meta-analysis, Oceanography, chemistry, 13. Climate action, Benthic zone, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, france
Abstract: International audience; In coastal systems, the multiplicity of sources fueling the pool of particulate organic matter (POM) leads to divergent estimations of POM composition. Eleven systems (two littoral systems, eight embayments and semi-enclosed systems and one estuary) distributed along the three maritime façades of France were studied for two to eight years in order to quantify the relative contribution of organic matter sources to the surface-water POM pool in coastal systems. This study was based on carbon and nitrogen elemental and isotopic ratios, used for running mixing models. The POM of the estuary is dominated by terrestrial material (93% on average), whereas the POM of the other systems is dominated by phytoplankton (84% on average). Nevertheless, for the latter systems, the POM composition varies in space, with 1) systems where POM is highly composed of phytoplankton (≥ 93%), 2) systems characterized by a non-negligible contribution of benthic (8 to 19%) and/or riverine (7 to 19%) sources, and 3) the Mediterranean systems characterized by the contribution of diazotroph organisms (ca. 14%). A continent-to-ocean gradient of riverine and/or benthic POM contribution is observed. Finally, time series reveal 1) seasonal variations of POM composition, 2) differences in seasonality between systems, and 3) an inshore-offshore gradient of seasonality within each system that were sampled at several stations. Spatial and seasonal patterns of POM composition are mainly due to local to regional processes such as hydrodynamics and sedimentary hydrodynamic (e.g. resuspension processes, changes in river flows, wind patterns influencing along-shore currents) but also due to the geomorphology of the systems (depth of the water column, distance to the shore). Future studies investigating the link between these forcings and POM composition would help to better understand the dynamics of POM composition in coastal systems.
Published: 2017

22. Carbon and nitrogen elemental and isotopic ratios of filter-feeding bivalves along the French coasts: An assessment of specific, geographic, seasonal and multi-decadal variations

Author: Nicolas Briant, Karine Charlier, Jeroen E. Sonke, Valérie David, Joël Knoery, Samuel Rodriguez, Christophe Brach-Papa, Tiphaine Chouvelon, Jean François Chiffoleau, and Nicolas Savoye
Subjects: 0106 biological sciences, Environmental Engineering, 010504 meteorology & atmospheric sciences, Nitrogen, Biology, 01 natural sciences, Mediterranean sea, Spatio-Temporal Analysis, Phytoplankton, Littoral zone, Mediterranean Sea, Environmental Chemistry, Animals, Ecosystem, Waste Management and Disposal, Atlantic Ocean, 0105 earth and related environmental sciences, Trophic level, Carbon Isotopes, Primary producers, δ13C, Nitrogen Isotopes, Ecology, 010604 marine biology & hydrobiology, Pollution, Carbon, Bivalvia, Oceanography, Spatial variability, France, Seasons
Abstract: Primary consumers play a key role in coastal ecosystems by transferring organic matter from primary producers to predators. Among them, suspension-feeders, like bivalve molluscs are widely used in trophic web studies. The main goal of this study was to investigate variations of C and N elemental and isotopic ratios in common bivalves (M. edulis, M. galloprovincialis, and C. gigas) at large spatial (i.e. among three coastal regions) and different temporal (i.e. from seasonal to multi-decadal) scales in France, in order to identify potential general or specific patterns and speculate on their drivers. The observed spatial variability was related to the trophic status of the coastal regions (oligotrophic Mediterranean Sea versus meso- to eutrophic English Channel and Atlantic ocean), but not to ecosystem typology (estuaries, versus lagoons versus bays versus littoral systems). Furthermore, it highlighted local specificities in terms of the origin of the POM assimilated by bivalves (e.g., mainly continental POM vs. marine phytoplankton vs. microphytobenthic algae). Likewise, seasonal variability was related both to the reproduction cycle for C/N ratios of Mytilus spp. and to changes in trophic resources for δ13C of species located close to river mouth. Multi-decadal evolution exhibited shifts and trends for part of the 30-year series with decreases in δ13C and δ15N. Specifically, shifts appeared in the early 2000's, likely linking bivalve isotopic ratios to a cascade of processes affected by local drivers.
Published: 2017

23. Trophic resource use by macrozoobenthic primary consumers within a semi-enclosed coastal ecosystem: Stable isotope and fatty acid assessment

Author: Aurélie Garcia, Karine Charlier, Gaël Guillou, Nicolas Savoye, Robert Galois, Pierre Richard, Hugues Blanchet, Antoine Grémare, Marjorie Massé, and Sophie Dubois
Subjects: chemistry.chemical_classification, Zostera noltei, Detritus, Ecology, fungi, Detritivore, Aquatic Science, Biology, Oceanography, biology.organism_classification, Seagrass, chemistry, Benthic zone, Organic matter, Ecosystem, Ecology, Evolution, Behavior and Systematics, Trophic level
Abstract: The diet of different macrozoobenthic trophic groups was investigated in the Arcachon Bay—a semi-enclosed macrotidal ecosystem that shelters the largest Zostera noltei s eagrass meadow in Europe—in early spring and late summer 2009, using stable isotopes and fatty acids. Fatty acid profiles and literature information about the biology and physiology of benthic consumers were combined to identify the main organic matter sources for the benthic primary consumers. An isotope mixing model was then run to evaluate the contribution of each organic matter source to each identified trophic group (suspension feeders, sub-surface deposit feeders, micro-and macrograzers, suspension-oriented interface feeders and deposit-oriented interface feeders). Variations in organism' diets with respect to both habitats (intertidal seagrass meadows, intertidal bare sediments and subtidal bare sediments) and study periods were also investigated. At the scale of this study, it appeared that the diet of macrozoobenthos primary consumers was based exclusively on autochthonous material (no use of terrestrial organic matter): mainly microphytobenthos, seagrasses and their epiphytes, and phytoplankton. In addition, the different trophic groups relied on different organic matter pools: for instance, suspension feeders mainly fed on microphytobenthos and phytoplankton, whereas subsurface deposit feeders fed on microphytobenthos, decayed seagrasses and bacteria, and grazers mainly fed on microphytobenthos, and seagrasses and their epiphytes. The same pattern was observed in both early spring and late summer, indicating a stability of the benthic system at a six-month time scale. Finally our results showed that, in Arcachon Bay, the seagrass meadow directly or indirectly (through detritus) plays a significant role in the diet of most benthic consumers.
Published: 2014

24. Stable isotope ratios in bentho-demersal biota along a depth gradient in the bay of biscay: A multitrophic study

Author: Anne Lorrain, Gauthier Schaal, Jean-Michel Mortillaro, Anik Brind'Amour, Hervé Le Bris, Jacques Grall, Yves-Marie Paulet, Caroline Nerot, Nicolas Savoye, Tiphaine Chouvelon, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de Brest (UBO), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Écologie et Modèles pour l'halieutique (EMH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, 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), 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), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Écologie et Modèles pour l'Halieutique (IFREMER EMH), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), and 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)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)
Subjects: 0106 biological sciences, Bivalves, crassostrea-gigas, nitrogen isotopes, 010504 meteorology & atmospheric sciences, coastal, Aquatic Science, Biology, Oceanography, Trophic, 01 natural sciences, delta-n-15, continental-shelf, 14. Life underwater, 0105 earth and related environmental sciences, Trophic level, δ13C, Ecology, Consumer, Stable isotope ratio, 010604 marine biology & hydrobiology, ACL, Biota, Food web, δ15N, 15. Life on land, Bay of Biscay, Diet, Fish, Coastal, 13. Climate action, Benthic zone, food webs, spatial-analysis, northeast atlantic, M40 - Écologie aquatique, trophic relationships, L20 - Écologie animale, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: 00003 ăWOS:000381531600019; International audience; Although stable isotope ratios are increasingly used to investigate the trophic ecology of marine organisms, their spatial variations are still poorly understood in the coastal environment. In this study, we measured the stable isotope composition (delta C-13, delta N-15) of suspended particulate organic matter (SPOM) (primary producer), a suspension feeder, the great scallop Pecten maximus (primary consumer), megabenthic decapods and benthic fishes (secondary consumers) along a depth gradient (from 5 m to 155 m depth) across the continental shelf of the Bay of Biscay. Although the three trophic levels exhibited similar delta C-13 patterns along the gradient, the delta N-15 patterns varied between SPOM, scallops and carnivores. The delta N-15 difference between SPOM and scallops decreased with increasing depth, suggesting that non trophic factors may affect the stable isotope composition of scallops at deepest sampling stations. An opposed trend was found between scallops and carnivores, suggesting that the trophic level of these carnivores increased at higher depth, possibly as an adaptation to lower prey abundances. Although our results suggest that primary consumers are suitable to establish isotopic baselines in coastal environments, we stress the need for further studies aiming at characterizing the variability of stable isotopes in coastal biota, and the respective effects of baseline, trophic and metabolic factors in their isotopic composition. (C) 2015 Elsevier Ltd. All rights reserved.
Published: 2016

25. Export and degassing of terrestrial carbon through watercourses draining a temperate podzolized catchment

Author: Dominique Poirier, Mathieu Canton, Pierre Polsenaere, Nicolas Savoye, Gwenaël Abril, Steven Bouillon, and Henri Etcheber
Subjects: Hydrology, geography, Detritus, geography.geographical_feature_category, Ecology, Drainage basin, chemistry.chemical_element, Aquatic Science, Particulates, Catchment scale, Podzol, chemistry, Temperate climate, Environmental science, Water cycle, Carbon, Ecology, Evolution, Behavior and Systematics, Water Science and Technology
Abstract: We measured spatial and temporal variations in carbon concentrations, isotopic compositions and exports during a complete hydrological cycle in nine watercourses draining a lowland forested podzolized catchment, flowing into the Arcachon lagoon (France). In addition, integrated fluxes of CO2 across the water-atmosphere interface were estimated to assess the relative importance of CO2 evasion versus lateral carbon transport at the catchment scale. Watercourse similarities and specificities linked to the local catchment characteristics are discussed and compared with other riverine systems. Low concentrations of suspended particulate matter and particulate organic carbon (POC) were generally measured in all the watercourses (8. 4 ± 3. 4 and 1. 6 ± 0. 6 mg L-1, respectively), reflecting limited mechanical soil erosion. The generally high POC content in the suspended matter (20 %), low Chl a concentrations (1. 3 ± 1. 4 μg L-1) and the relatively constant δ13C-POC value (near -28 ‰) throughout the year reveal this POC originates from terrestrial C3 plant and soil detritus. The presence of podzols leads to high levels of dissolved organic carbon (DOC; 6. 6 ± 2. 2 mg L-1). Similarly, high dissolved inorganic carbon (DIC) concentrations were measured in the Arcachon lagoon catchment (5. 9 ± 2. 2 mg L-1). The δ13C-DIC value around -20 ‰ throughout the year in many small watercourses reveals the predominance of terrestrial carbon mineralisation and silicate rock weathering in soils as the major DIC source. With pCO2 between 1,000 and 10,000 ppmv, all watercourses were a source of CO2 to the atmosphere, particularly during the low river stage. Organic carbon parameters remained relatively stable throughout the year, whereas DIC parameters showed strong seasonal contrasts closely linked to the hydrological regime and hyporheic flows. In total, the carbon export from the Arcachon watershed was estimated at 15,870 t C year-1 or 6 t C km-2 year-1, mostly exported to the lagoon as DOC (35 %), DIC (24 %) and lost as CO2 degassing to the atmosphere (34 %). © 2012 Springer Basel AG. ispartof: Aquatic Sciences vol:75 issue:2 pages:299-319 status: published
Published: 2012

26. Origin and composition of particulate organic matter in a macrotidal turbid estuary: The Gironde Estuary, France

Author: Isabelle Billy, François Morisseau, Henri Etcheber, Hervé Derriennic, Benoît Sautour, Nicolas Savoye, Gwenaël Abril, Karine Charlier, Valérie David, and Georges Oggian
Subjects: geography, geography.geographical_feature_category, Continental shelf, Pelagic zone, Estuary, Aquatic Science, Plankton, Oceanography, Benthic zone, Phytoplankton, Dissolved organic carbon, Littoral zone, Environmental science
Abstract: At the interface between continent and ocean, estuaries receive particles, and especially particulate organic matter (POM) originating from these two reservoirs, but also produce POM, through autochthonous primary production. The origin and composition of surface POM in the Gironde Estuary (SW France) and the environmental forcing of its variability was investigated using the data set produced by the French Coastal Monitoring Network SOMLIT (Service d'Observation en Milieu LITtoral; monthly like sampling during years 2007–2009). This estuary is considered as a model of macrotidal turbid estuaries. Using elemental and isotopic composition of the POM, we estimated that, at the inner estuary space scale and inter-annual time scale, surface particulate organic carbon (POC) was composed of terrestrial POM originated from the turbidity maximum (96.4%; refractory POC) and flood events (1.6%; labile and refractory POC), and of riverine (0.1%), estuarine (0.8%) and marine (1.1%) phytoplankton, i.e. that POC was 98% and 2% of terrestrial and phytoplankton origin, respectively. However, there was a clear spatial gradient: the phytoplankton contribution increases from ca. 1% in the upper and middle estuary to 8.5% in the lower estuary, where light condition is more favourable to plankton growth. The low contribution of phytoplankton to the POC is a characteristic of the Gironde estuary and contrast with other large temperate estuaries. Statistical analysis indicates that salinity, river flow and SPM concentration, and thus associated hydro-dynamic and sedimentary processes, were the only environmental forcings to the composition of surface POC in this system, at intra- and inter-annual time scale. In contrast, temperature and nutrient concentrations, and thus associated processes, do not force this composition of POC. By combining POC fluxes entering the inner estuary (literature data), POC loss as dissolved organic carbon and CO 2 and as sediment trapping within the inner estuary (literature data), and our estimate of the composition of POC flux at the mouth of the estuary (96% and 4% of terrestrial and phytoplankton origin), a first-order net export of POC originating from the Gironde to the continental shelf was estimated: it amounts 48,150 tC yr −1 , and is composed of 46,200 tC yr −1 of terrestrial material and of 1950 tC yr −1 of estuarine phytoplankton. POC exported by the Gironde Estuary is thus poorly bioavailable for shelf pelagic and benthic food webs.
Published: 2012

27. The buffering capacity of a small estuary on nutrient fluxes originating from its catchment (Leyre estuary, SW France)

Author: Mathieu Canton, Pierre Anschutz, Nicolas Savoye, Dominique Poirier, Romain Chassagne, and Jonathan Deborde
Subjects: chemistry.chemical_classification, geography, Nutrient cycle, geography.geographical_feature_category, Drainage basin, Estuary, Aquatic Science, Oceanography, Salinity, Nutrient, chemistry, Environmental chemistry, Dissolved organic carbon, Environmental science, Organic matter, Phosphorus cycle
Abstract: This work studied the impact of a small estuary (a 4 km-long estuary, at the interface between the Leyre River and the Arcachon lagoon, SW France) with a short flushing time on continental nutrient loads to a coastal lagoon. While large estuaries are known to modify the nutrient load of rivers to the coast, the impact on continental fluxes of a short salinity gradient from small coastal rivers is rarely studied. A survey of nutrient and dissolved organic matter concentration, particulate phosphorus speciation and particulate organic matter (POM) concentration and characteristics (C:N ratio and particulate organic carbon δ 13 C) showed that the estuarine behaviour varied throughout the year. The autochthonous primary production was a sink of dissolved N, P and Si in spring. During this period, the continental load of dissolved nitrogen was reduced by about 1/3 and phosphorus was totally consumed by estuarine processes. Nutrient recycling occurred in summer with ammonium production although this source was low in comparison with continental fluxes of nitrogen. The phosphorus concentration was dominated by the iron oxides-bound fraction. Contrary to large estuaries, the desorption of particulate phosphorus was not a source of dissolved phosphorus. Our results showed that estuarine processes impacted the net nutrient fluxes during productive periods, although estuarine residence time was very short. Passive transport with conservative mixing of nutrient was observed in autumn and winter. The non-conservative behaviour of small estuaries must be taken into account for nutrient mass balance calculation in lagoon.
Published: 2012

28. Isotopic constraints on the Si-biogeochemical cycle of the Antarctic Zone in the Kerguelen area (KEOPS)

Author: François Fripiat, Anne-Julie Cavagna, Nicolas Savoye, Damien Cardinal, Luc André, and Frank Dehairs
Subjects: Biogeochemical cycle, Mixed layer, Stratification (water), General Chemistry, Biogenic silica, Oceanography, Atmospheric sciences, Isotope fractionation, Circumpolar deep water, Environmental Chemistry, Seawater, Photic zone, Geology, Water Science and Technology
Abstract: Estimation of the silicon (Si) mass balance in the ocean from direct measurements (Si uptake-dissolution rates …) is plagued by the strong temporal and spatial variability of the surface ocean as well as methodological artifacts. Tracers with different sensitivities toward physical and biological processes would be of great complementary use. Silicon isotopic composition is a promising proxy to improve constraints on the Si-biogeochemical cycle, since it integrates over longer timescales in comparison with direct measurements and since the isotopic balance allows to resolve the processes involved, i.e. uptake, dissolution, mixing. Si-isotopic signatures of seawater Si(OH)4 and biogenic silica (bSiO2) were investigated in late summer 2005 during the KEOPS experiment, focusing on two contrasting biogeochemical areas in the Antarctic Zone: a natural iron-fertilized area above the Kerguelen Plateau ( 1000 m water depth). For the HNLC area the Si-isotopic constraint identified Upper Circumpolar Deep Water as being the ultimate Si-source. The latter supplies summer mixed layer with 4.0 ± 0.7 mol Si m− 2 yr− 1. This supply must be equivalent to the net annual bSiO2 production and exceeds the seasonal depletion as estimated from a simple mixed layer mass balance (2.5 ± 0.2 mol Si m− 2 yr− 1). This discrepancy reveals that some 1.5 ± 0.7 mol Si m− 2 yr− 1 must be supplied to the mixed layer during the stratification period. For the fertilized plateau bloom area, a low apparent mixed layer isotopic fractionation value (∆30Si) probably reflects (1) a significant impact of bSiO2 dissolution, enriching the bSiO2 pool in heavy isotope; and/or (2) a high Si uptake over supply ratio in mixed layer at the beginning of the bloom, following an initial closed system operating mode, which, however, becomes supplied toward the end of the bloom (low Si uptake over supply ratio) with isotopically light Si(OH)4 from below when the surface Si(OH)4 pool is significantly depleted. We estimated a net integrated bSiO2 production of 10.5 ± 1.4 mol Si m− 2 yr− 1 in the AASW above the plateau, which includes a significant contribution of bSiO2 production below the euphotic layer. However, advection which could be significant for this area has not been taken into account in the latter estimation based on a 1D approach of the plateau system. Finally, combining the KEOPS Si-isotopic data with those from previous studies, we refined the average Si-isotopic fractionation factor to − 1.2 ± 0.2‰ for the Antarctic Circumpolar Current.
Published: 2011

29. Determination of diet in Manila clams by spatial analysis of stable isotopes

Author: Cécile Dang, Pierre-Guy Sauriau, Nicolas Savoye, Nathalie Caill-Milly, Philippe Martinez, Joel Haure, X. de Montaudouin, C. Millaret, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: 0106 biological sciences, Delta, Mixing model, Drainage basin, Ruditapes, Aquatic Science, Spatial variability, 010603 evolutionary biology, 01 natural sciences, Trophic sources, Ruditapes philippinarum, SW France, Phytoplankton, Sedimentary organic matter, 14. Life underwater, Zostera, Ecology, Evolution, Behavior and Systematics, Trophic level, geography, geography.geographical_feature_category, C and N stable isotopes, Ecology, biology, 010604 marine biology & hydrobiology, Arcachon Bay, biology.organism_classification, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, Oceanography, Muscle, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition, Bay
Abstract: Spatial changes in the dietary regime of Ruditapes philippinarum from intertidal sediments of Arcachon Bay were depicted by analyzing stable isotope ratios in both its adductor muscles and potential trophic sources. Manila clams were collected from 50 sites in May to June 2006. Dietary reconstruction was based on the IsoSource mixing model, considering trophic enrichments of 3.5%. for carbon and 3.0%. for nitrogen, which were determined experimentally. delta C-13 and delta N-15 values, respectively, averaged -28.2 and 5.2 parts per thousand for riverine particulate organic matter (POM), -20.6 and 4.7 parts per thousand for inner bay phytoplankton, -21.0 and 5.6%. for outer bay phytoplankton, -16.8 and 4.8 parts per thousand. for microphytobenthos, -18.4 and 3.9 parts per thousand. for sedimentary organic matter (SOM) and 11.8 and 4.0 parts per thousand. for Zostera noltii. Clam muscle delta C-13 and delta N-15 values ranged from -20.5 to -16.4 parts per thousand., and from 7.6 to 9.3 parts per thousand., respectively. delta N-15 significantly decreased from southern to northern parts of the bay, while delta C-13 values increased with tidal elevation. Outer bay phytoplankton was the major diet component of clams. Clams from the southeast mainly incorporated outer bay phytoplankton despite the proximity of the Leyre River, whereas clams from the northwest incorporated approximately equal parts of inner and outer bay phytoplankton, riverine POM, microphytobenthos and SOM. These patterns were consistent with spatial gradients driven by the dominant role of tidal hydrodynamics within the bay and land-use characteristics of the catchment.
Published: 2009

30. Barium in twilight zone suspended matter as a potential proxy for particulate organic carbon remineralization: Results for the North Pacific

Author: Christophe Monnin, Stéphan Jacquet, F.A. Dehairs, Ken O. Buesseler, B. A. S. Van Mooy, Carl H. Lamborg, Nicolas Savoye, Marc Elskens, Willy Baeyens, Karen L. Casciotti, Philip W. Boyd, and James K. B. Bishop
Subjects: Total organic carbon, Remineralisation, Oceanography, Water column, chemistry, Mesopelagic zone, Mixed layer, chemistry.chemical_element, Barium, Particulates, Subarctic climate, Geology
Abstract: This study focuses on the fate of exported organic carbon in the twilight zone at two contrasting environments in the North Pacific: the oligotrophic ALOHA site (22°45′N, 158°W; Hawaii; studied during June–July 2004) and the mesotrophic Subarctic Pacific K2 site (47°N, 161°W; studied during July–August 2005). Earlier work has shown that non-lithogenic, excess particulate Ba (Baxs) in the mesopelagic water column is a potential proxy of organic carbon remineralization. In general, Baxs contents were significantly larger at K2 than at ALOHA. At ALOHA, the Baxs profiles from repeated sampling (five casts) showed remarkable consistency over a period of three weeks, suggesting that the system was close to being at steady state. In contrast, more variability was observed at K2 (six casts sampled), reflecting the more dynamic physical and biological conditions prevailing in this environment. While for both sites Baxs concentrations increased with depth, at K2 a clear maximum was present between the base of the mixed layer at around 50 and 500 m, reflecting production and release of Baxs. Larger mesopelagic Baxs contents and larger bacterial production in the twilight zone at the K2 site indicate that more material was exported from the upper mixed layer for bacterial degradation deeper, compared to the ALOHA site. Furthermore, application of a published transfer function [Dehairs, F., Shopova, D., Ober, S., Veth, C., Goeyens, L., 1997. Particulate barium stocks and oxygen consumption in the Southern Ocean mesopelagic water column during spring and early summer: relationship with export production. Deep-Sea Research II 44(1–2), 497–516] relating oxygen consumption to the observed Baxs data indicated that the latter were in good agreement with bacterial respiration, calculated from bacterial production. These results corroborate earlier findings highlighting the potential of Baxs as a proxy for organic carbon remineralization. The range of POC remineralization rates calculated from twilight zone excess particulate Ba contents also compared well with the depth dependent POC flux decrease as recorded by neutrally buoyant sediment traps, except in one case (out of four). This discrepancy could indicate that differences in sinking velocities cause an uncoupling of the processes occurring in the fine suspended particle pool from those affecting the larger particle pool which sustains the vertical flux, thus rendering comparison between both approaches risky.
Published: 2008

31. 234Th-based export fluxes during a natural iron fertilization experiment in the Southern Ocean (KEOPS)

Author: Frank Dehairs, Thomas W. Trull, Nicolas Savoye, Stephanie Jacquet, and Jacques Navez
Subjects: Total organic carbon, geography, Plateau, geography.geographical_feature_category, Oceanography, Phytoplankton, Iron fertilization, Environmental science, Ecosystem, Plankton, Bloom, Carbon cycle
Abstract: Five iron-fertilization experiments in the Southern Ocean have clearly demonstrated that adding iron increases primary production, but the implications for carbon export to the ocean interior have been less clear. This reflects both observational limitations of short-term experiments and their uncertain relevance to quantifying ecosystem level processes that are likely to be structured differently under conditions of punctual versus persistent stimulation. To avoid these biases, KEOPS (KErguelen Ocean and Plateau compared Study) investigated the naturally iron-fertilized Kerguelen Plateau region in the Indian Sector of the Southern Ocean that exhibits an annual phytoplankton bloom. Here, we report particulate organic carbon (POC) and nitrogen export from this system based on the 234 Th approach. Results indicate that the export fluxes were variable both on and off the Kerguelen Plateau (9.0–38.4 mmol C m −2 d −1 and 1.6–4.8 mmol N m −2 d −1 ) and were in the range of values reported for natural Southern Ocean ecosystems. Export fluxes were compared at two reference stations, one above and one outside the Plateau. The station above the plateau was characterized by higher iron supply and export fluxes compared to the station outside the plateau. The difference in the export flux between these two reference stations defines the export excess induced by iron fertilization. It was 10.8±4.9 mmol C m −2 d −1 and 0.9±0.7 mmol N m −2 d −1 at 100 m, and 14.2±7.7 mmol C m −2 d −1 and 2.0±1.3 mmol N m −2 d −1 at 200 m. This POC export excess was similar to those found during other studies of artificial (SOFeX) and natural (CROZEX) iron fertilization in the Southern Ocean. The examination of the export efficiency (defined as the ratio of export to primary production) revealed significant variability over the plateau related to the temporal decoupling of production and export during the demise of the bloom. On average, the export efficiency was lower over the plateau than in surrounding waters, suggesting that increased iron supply may increase total export but lower export efficiency. Our findings are very important for evaluating present and past carbon cycling in the Southern and global oceans and for assessing predictive scenarios of carbon cycling and budget.
Published: 2008

32. Spring phytoplankton assemblages in the Southern Ocean between Australia and Antarctica

Author: Nicolas Savoye, Damien Cardinal, Marc Elskens, Elzbieta E. Kopczynska, and Frank Dehairs
Subjects: Diatom, Oceanography, Productivity (ecology), Ecology, Phytoplankton, Chaetoceros, Autotroph, Gymnodinium, New production, Biology, General Agricultural and Biological Sciences, biology.organism_classification, Zooplankton
Abstract: Variations of phytoplankton assemblages were studied in November–December 2001, in surface waters of the Southern Ocean along a transect between the Sub-Antarctic Zone (SAZ) and the Seasonal Ice Zone (SIZ; 46.9°–64.9°S; 142°–143°E; CLIVAR-SR3 cruise). Two regions had characteristic but different phytoplankton assemblages. Nanoflagellates( 20 μm), diatoms and dinoflagellates, were more abundant in the Antarctic Zone-South (AZ-S) and the SIZ, (60.9°–64.9°S). In AZ-S and SIZ diatoms ranged between 2.7 × 105 and 1.2 × 106 cells l−1, dinoflagellates from 3.1 × 104 to 1.02 × 105 cells l−1. A diatom bloom was in progress in the AZ-S showing a peak of 1.8 × 106 cells l−1. Diatoms were dominated by Pseudo-nitzschia spp., Fragilariopsis spp., and Chaetoceros spp. Pseudo-nitzschia spp. outnumbered other diatoms in the AZ-S. Fragilaropsis spp. were most numerous in the SIZ. Dinoflagellates contained autotrophs (e.g. Prorocentrum) and heterotrophs (Gyrodinium/Gymnodinium, Protoperidinium). Diatoms and dinoflagellates contributed most to the cellular carbon: 11–25 and 17–124 μg C l−1, respectively. Small cells dominated in the northern region characterized by the lowest N-uptake and new production of the transect. Larger diatom cells were prevalent in the southern area with higher values of N-uptake and new production. Diatom and nanoflagellate cellular carbon contents were highly correlated with one another, with primary production, and productivity related parameters. They contributed up to 75% to the total autotrophic C biomass. Diatom carbon content was significantly correlated to nitrate uptake and particle export, but not to ammonium uptake, while flagellate carbon was well correlated to ammonium uptake, but not to export. Diatoms have contributed highly to particle export along the latitudinal transect, while flagellates played a minor role in the export.
Published: 2007

33. Silicon isotopes in spring Southern Ocean diatoms: Large zonal changes despite homogeneity among size fractions

Author: Thomas W. Trull, Nicolas Savoye, Damien Cardinal, Elzbieta E. Kopczynska, Jean-Louis Tison, Frank Dehairs, Luc André, and François Fripiat
Subjects: Polar front, biology, Mineralogy, General Chemistry, Biogenic silica, Oceanography, biology.organism_classification, Equilibrium fractionation, Chemical oceanography, chemistry.chemical_compound, Diatom, Isotope fractionation, chemistry, Environmental Chemistry, Seawater, Silicic acid, Geology, Water Science and Technology
Abstract: We determine Southern Ocean diatom silicon isotopic signatures and compare them with the previously published data for dissolved silicic acid from the same locations. Five stations distributed along the WOCE SR-3 transect (Australian Sector of the Southern Ocean) in different biogeochemical provinces are presented: Polar Front and Inter-Polar Front Zones (PFZ–IPFZ), Southern Antarctic Zone (AZ-S), Seasonal Ice Zone (SIZ). Total (N0.4 μm), medium-sized (20–70 μm), and large diatoms (N70 μm) were sampled at 2–4 depths in the upper 150 m. Silicon isotopic compositions of biogenic silica (diatoms) and seawater were then measured by MC-ICP-MS, in dry plasma mode using external Mg doping. Results are expressed as δ 29 Si relative to the NBS28 standard. The isotopic composition of diatoms (δ 29 SiBSi) is generally homogeneous in the mixed layer and does not exhibit a systematic isotopic fractionation linked to a size effect. δ 29 SiBSi are always lighter than the ambient dissolved silicic acid signatures (δ 29 SiDSi), reflecting the preferential uptake of light isotopes by diatoms. A trend of lighter isotopic signatures southward is observed both in diatoms and seawater samples but the δ 29 SiBSi latitudinal gradient is much steeper. A diatom signature as low as −0.26‰ in the southernmost SIZ station strongly contrasts with the +0.65‰ signature measured on PFZ diatoms. The difference between the ambient dissolved silicic acid and diatom isotopic signatures, Δ 29 Si, strongly increases southward: from 0.4 in the PFZ up to 1.08‰ in the SIZ. This points toward occurrence of mixing events in the PFZ–IPFZ with diatoms not being under equilibrium with their surrounding water and/or, possible variation of the diatom–seawater equilibrium fractionation factor, 29 e. Apart from mixing, we found that the other parameters likely responsible of such variation are temperature, dissolved Si contents and, Si specific uptake and dissolution rates although at this stage none of these could be clearly recognized as the leading cause. Thorough examination of these parameters through in vitro experiments reflecting the extreme Southern Ocean conditions is needed to determine whether the observed latitudinal variation of Δ 29 Si reflects real variable fractionation or results from nonequilibrium or different time-scales recorded between dissolved and biogenic Si isotopic signatures. Our results also call for the development of more realistic models for describing short-term isotopic composition changes due to e.g. Si consumption, export
Published: 2007

34. Barium cycling along WOCE SR3 line in the Southern Ocean

Author: Stephanie Jacquet, Marc Elskens, Frank Dehairs, Nicolas Savoye, Damien Cardinal, Analytical and Environmental Chemistry, and Chemistry
Subjects: Polar front, Alkalinity, chemistry.chemical_element, Barium, Southern Ocean, Ba-nutrients, General Chemistry, Particulates, Oceanography, Atmospheric sciences, Silicate, chemistry.chemical_compound, chemistry, Environmental Chemistry, Seawater, Dissolution, Surface water, Geology, Water Science and Technology
Abstract: Spring and summer profiles of dissolved and particulate barium (Ba) from WOCE SR3 line (145°E) in the Southern Ocean are compared and seasonal evolutions discussed. Fluxes are estimated from mass conservation equations and from differences in reservoir contents between seasons. Subtraction of barium is observed at mesopelagic depths (upper 600 m) and appears to exceed up to tenfold the combined local build-up and the deep-ocean fluxes of particulate Ba, pointing towards significant dissolution to take place in intermediate and deep waters. Although regression analyses identify silicate as the major predictor of dissolved Ba, Ba and silicate are clearly uncoupled in surface waters where Ba behaves more similar to nitrate, excluding diatoms as users of Ba. Moreover, we observe a southward decrease in the Ba vs. silicate regression slopes driven by the conditions in intermediate and deep waters and mainly marked by the location of the Polar Front. These findings corroborate existing knowledge about the predominant control by barite formation and dissolution on the oceanic Ba cycle. It suggests a decreased dissolution of barite south of the Polar Front as compared to the situation in the Polar Front Zone and the Subantarctic Zone. This is in agreement with the fact that, except for deep waters, the Antarctic Circumpolar Current water column is oversaturated with respect to barite, in contrast to the situation north of the Polar Front, where the whole water column is undersaturated [Jeandel C., B. Dupre, G. Lebaron, C. Monnin and J.F. Minster, 1996. Longitudinal distributions of dissolved barium, silica and alkalinity in the western and southern Indian Ocean. Deep-Sea Res. 1, 43 (1), 1-31; Monnin, C., C. Jeandel, T. Cattaldo and F. Dehairs, 1999. The marine barite saturation state of the world's ocean. Mar. Chem., 65, 253-261].
Published: 2007

35. A review of present techniques and methodological advances in analyzing 234Th in aquatic systems

Author: Manmohan Sarin, Mark Baskaran, Matthew A. Charette, Paul J. Morris, Robert Turnewitsch, Claudia R. Benitez-Nelson, K.A. Orlandini, Ingrid Vöge, Michiel M Rutgers van der Loeff, Alessia M. Rodriguez y Baena, Örjan Gustafsson, Sabine Schmidt, Pere Masqué, Ken O. Buesseler, Minhan Dai, James T. Waples, and Nicolas Savoye
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Aquatic ecosystem, Analytical technique, Sampling (statistics), Sample (statistics), General Chemistry, Oceanography, 01 natural sciences, 6. Clean water, Variety (cybernetics), Flow chart, 13. Climate action, Environmental Chemistry, 14. Life underwater, Biochemical engineering, Physical geography, Freshwater systems, Strengths and weaknesses, Geology, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: The short-lived thorium isotope 234Th (half-life 24.1 days) has been used as a tracer for a variety of transport processes in aquatic systems. Its use as a tracer of oceanic export via sinking particles has stimulated a rapidly increasing number of studies that require analyses of 234Th in both marine and freshwater systems. The original 234Th method is labor intensive. Thus, there has been a quest for simpler techniques that require smaller sample volumes. Here, we review current methodologies in the collection and analysis of 234Th from the water column, discuss their individual strengths and weaknesses, and provide an outlook on possible further improvements and future challenges. Also included in this review are recommendations on calibration procedures and the production of standard reference materials as well as a flow chart designed to help researchers find the most appropriate 234Th analytical technique for a specific aquatic regime and known sampling constraints.
Published: 2006

36. 234Th sorption and export models in the water column: A review

Author: Matthew A. Charette, Nicolas Savoye, Ken O. Buesseler, Matthieu Roy-Barman, Marc Elskens, J. Kirk Cochran, George A. Jackson, Claudia R. Benitez-Nelson, Sabine Schmidt, Adrian B. Burd, Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), University of South Carolina [Columbia], Stony Brook University [SUNY] (SBU), State University of New York (SUNY), Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Texas A&M University [College Station], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochimie Des Impacts (GEDI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Meteorology, Physical oceanography, Oceanography, Atmospheric sciences, 01 natural sciences, Pacific ocean, Water column, Particle dynamics, Environmental Chemistry, 14. Life underwater, 0105 earth and related environmental sciences, Water Science and Technology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, model, $^{234}$Th, 010604 marine biology & hydrobiology, Sorption, General Chemistry, scavenging, Field (geography), particle dynamics, High flux, 13. Climate action, [SDE]Environmental Sciences, export, Geology
Abstract: Over the past few decades, the radioisotope pair of 238U / 234Th has been widely and increasingly used to describe particle dynamics and particle export fluxes in a variety of aquatic systems. The present paper is one of five review articles dedicated to 234Th. It is focused on the models associated with 234Th whereas the companion papers (same issue) are focused on present and future methodologies and techniques (Rutgers van der Loeff et al.), C / 234Th ratios (Buesseler et al.), 234Th speciation (Santschi et al.) and present and future applications of 234Th [Waples, J.T., Benitez-Nelson, C.R., Savoye, N., Rutgers van der Loeff, M., Baskaran, M., Gustafsson, O., this issue. An Introduction to the application and future use of 234Th in aquatic systems. Marine Chemistry, FATE special issue]. In this paper, we review current 234Th scavenging models and discuss the relative importance of the non-steady state and physical terms associated with the most commonly used model to estimate 234Th flux. Based on this discussion we recommend that for future work the use of models should be accompanied by a discussion of the effect that model and data uncertainty have on the model results. We also suggest that future field work incorporate repeat occupations of sample sites on time scales of 1–4 weeks in order to evaluate steady state versus non-steady state estimates of 234Th export, especially during high flux events (> ca. 800 dpm m− 2 d− 1). Finally, knowledge of the physical oceanography of the study area is essential, particularly in ocean margins and in areas of established upwelling (e.g., Equatorial Pacific). These suggestions will greatly enhance the application of 234Th as a tracer of particle dynamics and flux in more complicated regimes.
Published: 2006

37. An introduction to the application and future use of 234Th in aquatic systems

Author: Nicolas Savoye, Mark Baskaran, Michiel M Rutgers van der Loeff, Claudia R. Benitez-Nelson, James T. Waples, and Örjan Gustafsson
Subjects: 010504 meteorology & atmospheric sciences, business.industry, Aquatic ecosystem, Environmental resource management, Future application, Context (language use), General Chemistry, Biology, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, 6. Clean water, Natural (archaeology), Variety (cybernetics), 13. Climate action, Particle dynamics, Aquatic science, Environmental Chemistry, Lack of knowledge, 14. Life underwater, business, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: 234 Th is an extremely useful radiotracer of particle dynamics in aquatic systems. Its utility, however, has yet to be realized by many within the aquatic science community. The reasons for this may in part be due to a lack of knowledge of how this nuclide has been used in the past as well as how and where 234 Th might be profitably applied in future research. The purpose of this paper, then, is to examine the variety of 234 Th applications that have been used to understand natural aquatic processes in four major areas: vertical transport, particle cycling, horizontal transport, and sediment dynamics. We provide a general overview of the possible applications of 234 Th in the hopes of provoking an increased interest in the inherent potential and future application of 234 Th in these systems. We end this paper with a discussion of future research avenues in the context of three specific regimes: (i) the upper 1000 m of the open ocean, (ii) coastal sediment/water processes and (iii) large freshwater lakes.
Published: 2006

38. An assessment of particulate organic carbon to thorium-234 ratios in the ocean and their impact on the application of 234Th as a POC flux proxy

Author: Nicolas Savoye, Scott W. Fowler, Juan-Carlos Miquel, Carl H. Lamborg, Matthew A. Charette, J. K. Cochran, Pere Masqué, Wilford D. Gardner, Peter H. Santschi, Thomas W. Trull, Örjan Gustafsson, S.B. Moran, Ken O. Buesseler, Laurent Coppola, Uta Passow, Adrian B. Burd, Gillian Stewart, Nicholas S. Fisher, Claudia R. Benitez-Nelson, and Laodong Guo
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Chemistry, Mixed layer, 010604 marine biology & hydrobiology, Mineralogy, General Chemistry, Oceanography, Atmospheric sciences, 01 natural sciences, Chemical oceanography, Flux (metallurgy), Water column, Settling, 13. Climate action, TRACER, Sediment trap, Environmental Chemistry, 14. Life underwater, Particle size, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: Thorium-234 is increasingly used as a tracer of ocean particle flux, primarily as a means to estimate particulate organic carbon export from the surface ocean. This requires determination of both the 234 Th activity distribution (in order to calculate 234 Th fluxes) and an estimate of the C / 234 Th ratio on sinking particles, to empirically derive C fluxes. In reviewing C / 234 Th variability, results obtained using a single sampling method show the most predictable behavior. For example, in most studies that employ in situ pumps to collect size fractionated particles, C / 234 Th either increases or is relatively invariant with increasing particle size (size classes > 1 to 100s μm). Observations also suggest that C / 234 Th decreases with depth and can vary significantly between regions (highest in blooms of large diatoms and highly productive coastal settings). Comparisons of C fluxes derived from 234 Th show good agreement with independent estimates of C flux, including mass balances of C and nutrients over appropriate space and time scales (within factors of 2–3). We recommend sampling for C / 234 Th from a standard depth of 100 m, or at least one depth below the mixed layer using either large volume size fractionated filtration to capture the rarer large particles, or a sediment trap or other device to collect sinking particles. We also recommend collection of multiple 234 Th profiles and C / 234 Th samples during the course of longer observation periods to better sample temporal variations in both 234 Th flux and the characteristic of sinking particles. We are encouraged by new technologies which are optimized to more reliably sample truly settling particles, and expect the utility of this tracer to increase, not just for upper ocean C fluxes but for other elements and processes deeper in the water column.
Published: 2006

39. Amazon River carbon dioxide outgassing fuelled by wetlands

Author: Jonathan Deborde, L. Felipe Artigas, Luciana O. Vidal, Edivaldo Lima Souza, Marc F. Benedetti, Marcelo Friederichs Landim de Souza, Patrick Albéric, Nicolas Savoye, Jung-Hyun Kim, Fábio Roland, Gwenaël Abril, Tarik Meziane, Patricia Moreira-Turcq, Marcelo Bernardes, Jean-Michel Martinez, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), 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), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-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-Université Fédérale Toulouse Midi-Pyrénées-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), Laboratoire de géochimie des Eaux (LGE), Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris, Laboratório de Ecologia Aquática, Universidade Federal de Juiz de Fora (UFJF), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Departamento de Geoquímica, Universidade Federal Fluminense [Rio de Janeiro] (UFF), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), 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), 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]), Université du Littoral Côte d'Opale (ULCO), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), 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), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)
Subjects: 010504 meteorology & atmospheric sciences, Floodplain, Drainage basin, chemistry.chemical_element, Wetland, 010501 environmental sciences, 01 natural sciences, Carbon Cycle, Carbon cycle, chemistry.chemical_compound, Rivers, Water Movements, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Total organic carbon, Hydrology, geography, Multidisciplinary, geography.geographical_feature_category, Atmosphere, Ecology, Primary production, Carbon Dioxide, Plants, 15. Life on land, Lakes, chemistry, [SDU]Sciences of the Universe [physics], 13. Climate action, Wetlands, Carbon dioxide, Environmental science, Carbon, Brazil
Abstract: International audience; River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.
Published: 2014

40. Growth anomalies in Pecten maximus from coastal waters (Bay of Brest, France): relationship with diatom blooms

Author: Elisabeth Nézan, Yves-Marie Paulet, Nicolas Savoye, Laurent Guerin, Anne Lorrain, Laurent Chauvaud, 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), IFREMER-Concarneau, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), 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), Laboratoire Environnement Ressource Bretagne Nord (LERBN), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, SHELL, Aquatic Science, Biology, 01 natural sciences, SINKING, Algae, GIANT SCALLOP, Phytoplankton, Limiting factors, Pecten maximus, Biscay bay, 14. Life underwater, OF-BREST, 0105 earth and related environmental sciences, Primary production, Growth rate, Phytoplankton cnoncentration, Ecology, WESTERN-EUROPE, 010604 marine biology & hydrobiology, fungi, MACROTIDAL ECOSYSTEMS, PLACOPECTEN-MAGELLANICUS, Pelagic zone, Spring bloom, biology.organism_classification, Oceanography, Diatom, Benthic zone, [SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, NITRATE
Abstract: The aim of this study was to characterize the daily shell growth of Pecten maximus from early 1998 to late spring 1999 in the Bay of Brest with a careful qualitative and quantitative description of the pelagic primary production. Our results, in accordance with previous studies, demonstrate that there are episodic declines in the growth rate. Concurrent events of low growth rate and large bottom-concentrations of algae following diatom blooms (Cerataulina pelagica or Rhizosolenia delicatula), suggests that this high concentration of phytoplankton on the bottom layer may affect food intake or respiratory activity of the scallops by gill clogging or oxygen depletion. In this study, silicic acid or phosphorus are inferred to be limiting factors responsible for the collapse of the spring bloom. Further, we suggest that, in an N-enriched ecosystem, Si or P-limitation and the changing sinking velocities of phytoplankton, could affect the biology of benthic suspension-feeders.
Published: 2000

41. Sources of organic matter for flatfish juveniles in coastal and estuarine nursery grounds: A meta-analysis for the common sole (Solea solea) in contrasted systems of Western Europe

Author: Mireille Harmelin-Vivien, Gaël Beaunée, Catarina Vinagre, O. Le Pape, Henrique N. Cabral, Anik Brind'Amour, C. Kostecki, Julien Moderan, Susana França, Stéphanie Pasquaud, Nicolas Savoye, H. Le Bris, Pascal Riera, Audrey M. Darnaude, D. Nicolas, Ecogéochimie et Fonctionnement des Ecosystèmes Benthiques (EFEB), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), and 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)
Subjects: 0106 biological sciences, Common sole, 010504 meteorology & atmospheric sciences, Flatfish, Intertidal zone, Aquatic Science, Oceanography, 01 natural sciences, Benthos, Mixing model SIAR, Ecosystem, Organic matter, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Trophic level, Stable isotopes, chemistry.chemical_classification, geography, geography.geographical_feature_category, biology, Ecology, 010604 marine biology & hydrobiology, Nursery ground, biology.organism_classification, Fishery, chemistry, Organic matter origin, Benthic zone, Salt marsh, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: [Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASAREDocument Type : Proceedings Paper Conference Date : NOV 05-11, 2011 Conference Location : Ijmuiden, NETHERLANDS; Shallow and productive areas provide the high food supply that allows maximizing juvenile growth and survival in most flatfish species. However, the main organic matter sources at the basis of benthic food webs might differ drastically between estuarine nursery grounds under strong freshwater influences, where food webs are mainly supported by continental organic matter, and coastal ecosystems under limited freshwater influence, where the local marine primary production is the main source of carbon for the benthos. To better understand the links between continental inputs to the coastal zone and stock maintenance in the highly prized common sole, Solea solea (L.), we investigated the variability in the organic matter sources supporting the growth of its young-of-the-year (YoY) in five contrasted estuarine and coastal nursery grounds under varying freshwater influence. Stable isotopes of carbon and nitrogen allowed tracing the origin of the organic matter exploited by YoY soles in the very first months following their benthic settlement, i.e. when most of the juvenile mortality occurs in the species. A mixing model was run to unravel and quantify the contribution of all major potential sources of organic matter to sole food webs, with a sensitivity analysis allowing assessment of the impact of various trophic enrichment factors on model outputs. Thismeta-analysis demonstrated a relative robustness of the estimation of the respective contributions of the various organic matter sources. At the nursery scale, the upstream increase in freshwater organic matter exploitation by YoY soles and its positive correlation with inter-annual variations in the river flow confirmed previous conclusions about the importance of organic matter from continental origin for juvenile production. However, inter-site differences in the organic matter sources exploited for growth showed that, although freshwater organic matter use is significant in all nursery sites, it is never dominant, with especially high contributions of local primary production by microphytobenthos or saltmarsh macrophytes to juvenile sole growth in tidal nursery ecosystems. These patterns stress the need for maintaining both the intensity of freshwater inputs to the coastal zone and of local autochthonous primary production (especially that of the intertidal microphytobenthos) to preserve the nursery function of coastal and estuarine ecosystems.
Published: 2013

42. Deep carbon export from a Southern Ocean iron-fertilized diatom bloom

Author: Martin Losch, Matthew M. Mills, Philipp Assmy, Adrian Webb, Boris Cisewski, Gry Mine Berg, Jesús M. Arrieta, Jill Nicola Schwarz, Linn Hoffmann, Ulrich Bathmann, Volker Strass, Ilka Peeken, Harry Leach, Marina Montresor, Eberhard Sauter, Maike M. Schmidt, Victor Smetacek, Christine Klaas, Francesco d'Ovidio, Anja Terbrüggen, Dieter Wolf-Gladrow, Oliver Sachs, Joachim Henjes, Rüdiger Röttgers, Craig Neill, Gerhard J. Herndl, Richard G. J. Bellerby, Nicolas Savoye, Peter Croot, Santiago F. Gonzalez, Couplage physique-biogéochimie-carbone (PHYBIOCAR), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), 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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636))
Subjects: 0106 biological sciences, Carbon Sequestration, Time Factors, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Iron, Oceans and Seas, [SDE.MCG]Environmental Sciences/Global Changes, chemistry.chemical_element, cycles, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Carbon sequestration, 01 natural sciences, Atmosphere, chemistry.chemical_compound, Phytoplankton, 14. Life underwater, 0105 earth and related environmental sciences, Diatoms, Biomass (ecology), atmospheric co2, Multidisciplinary, model, biology, 010604 marine biology & hydrobiology, fungi, Carbon Dioxide, biology.organism_classification, Carbon, Diatom, Oceanography, chemistry, 13. Climate action, Carbon dioxide, Environmental science, sea-floor, Bloom
Abstract: International audience; Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncertain. Here we report the results of a five-week experiment carried out in the closed core of a vertically coherent, mesoscale eddy of the Antarctic Circumpolar Current, during which we tracked sinking particles from the surface to the deep-sea floor. A large diatom bloom peaked in the fourth week after fertilization. This was followed by mass mortality of several diatom species that formed rapidly sinking, mucilaginous aggregates of entangled cells and chains. Taken together, multiple lines of evidence--although each with important uncertainties--lead us to conclude that at least half the bloom biomass sank far below a depth of 1,000 metres and that a substantial portion is likely to have reached the sea floor. Thus, iron-fertilized diatom blooms may sequester carbon for timescales of centuries in ocean bottom water and for longer in the sediments.
Published: 2012

43. Origin and composition of sediment organic matter in a coastal semi-enclosed ecosystem: An elemental and isotopic study at the ecosystem space scale

Author: Karine Charlier, A. Beltoise, Swan Dubois, Antoine Grémare, Hugues Blanchet, Nicolas Savoye, and Martin Plus
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Primary producers, Aquatic Science, Oceanography, 01 natural sciences, Phytoplankton, Organic matter, Ecosystem, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, chemistry.chemical_classification, C and N stable isotopes, 010604 marine biology & hydrobiology, Sediment, 15. Life on land, Arcachon Bay, Zostera noltii, Sediment organic matter, chemistry, 13. Climate action, Granulometry, Environmental science, Spatial variability, Bay
Abstract: The origin and composition of sediment organic matter (SOM) were investigated together with its spatial distribution in the Arcachon Bay - a macrotidal lagoon that shelters the largest Zostera noltii meadow in Europe - using elemental and isotopic ratios. Subtidal and intertidal sediments and primary producers were both sampled in April 2009. Their elemental and isotopic compositions were assessed. Relative contributions of each source to SOM were estimated using a mixing model. The SOM composition tended to be homogeneous over the whole ecosystem and reflected the high diversity of primary producers in this system. On average, SOM was composed of 25% of decayed phanerogams, 19% of microphytobenthos, 20% of phytoplankton, 19% of river SPOM and 17% of macroalgae. There was no evidence of anthropogenic N-sources and SOM was mainly of autochthonous origin. None of the tested environmental parameters - salinity, current speed, emersion, granulometry and chlorophyll a - nor a combination of them explained the low spatial variability of SOM composition and characteristics. Resuspension, mixing and redistribution of the different particulate organic matters by wind-induced and tidal currents in combination with shallow depth probably explain the observed homogeneity at the whole bay scale. (C) 2011 Elsevier B.V. All rights reserved.
Published: 2012

44. Variation in particulate C and N isotope composition following iron fertilization in two successive phytoplankton communities in the Southern Ocean

Author: Richard G. J. Bellerby, Kevin R. Arrigo, Matthew C. Long, Matthew M. Mills, Rüdiger Röttgers, Nicolas Savoye, Gry Mine Berg, Volker Strass, Peter Croot, and Adrian Webb
Subjects: 0106 biological sciences, Polar front, Atmospheric Science, Global and Planetary Change, Biomass (ecology), 010504 meteorology & atmospheric sciences, Chemistry, Stable isotope ratio, 010604 marine biology & hydrobiology, Iron fertilization, Particulates, 01 natural sciences, Substrate (marine biology), Oceanography, Environmental chemistry, Phytoplankton, Environmental Chemistry, 14. Life underwater, Growth rate, 0105 earth and related environmental sciences, General Environmental Science
Abstract: [1] Surface δ15NPON increased 3.92 ± 0.48‰ over the course of 20 days following additions of iron (Fe) to an eddy in close proximity to the Antarctic Polar Front in the Atlantic sector of the Southern Ocean. The change in δ15NPON was associated with an increase in the >20 μm size fraction, leading to a maximal difference of 6.23‰ between the >20 μm and
Published: 2011

45. Silicon uptake and supply during a Southern Ocean iron fertilization experiment (EIFEX) tracked by Si isotopes

Author: Boris Cisewski, Frank Dehairs, Dieter Wolf-Gladrow, A.-J. Cavagna, Luc André, François Fripiat, Nicolas Savoye, and Damien Cardinal
Subjects: 0106 biological sciences, Hydrology, 010504 meteorology & atmospheric sciences, biology, Isotope, 010604 marine biology & hydrobiology, Iron fertilization, Fractionation, Aquatic Science, Biogenic silica, Oceanography, biology.organism_classification, Thermal diffusivity, 01 natural sciences, Diatom, Human fertilization, 13. Climate action, Environmental chemistry, Environmental science, 14. Life underwater, Bloom, 0105 earth and related environmental sciences
Abstract: We studied the evolution of the isotopic composition of dissolved Si (d30SiDSi) and biogenic Si (d30SiBSi) during a diatom bloom induced by an iron fertilization experiment in a Southern Ocean (SO) eddy. Dissolved Si (DSi) consumption was clearly boosted as a result of iron addition. We estimate an apparent Si isotopic fractionation factor of -1.36 parts per thousand +/- 0.11 parts per thousand, not significantly different from estimates based on in vitro incubations under Fe-replete conditions and in agreement with previous SO studies under Fe-depleted conditions. The temporal variations of the d30Si are best reconstructed considering the fertilized surface waters as an open system, i.e., DSi is continuously supplied from the winter water. Using vertical diffusivity, we estimate a supply of 6.7 +/- 1.2 mmol Si m-2 d-1 representing 30% +/- 5% of total DSi demand. We estimate biogenic silica (BSi) production at 22.1 +/- 1.8 mmol Si m-2 d-1, similar to BSi production under natural conditions in the SO. The DSi use preceding the start of the fertilization was conservatively estimated at 49% +/- 4%, and as a result of the Fe-fertilization, a further 31% +/- 4% of the initial DSi reservoir was consumed. The BSi export was estimated to be 17.4 +/- 1.7 mmol Si m-2 d-1. Our results suggest that for this study three main processes were acting significantly on d30Si signatures, biological uptake, Si supply from subsurface, and export of BSi, and that the magnitude of production and export in such a Fe-fertilized experiment are similar to those for natural diatom blooms occurring in the Southern Ocean.
Published: 2011

46. Digenean trematodes-marine mollusc relationships: a stable isotope study

Author: Pierre-Guy Sauriau, Nicolas Savoye, Isabelle Billy, Swan Dubois, X. de Montaudouin, and Philippe Martinez
Subjects: Male, Nitrogen, Zoology, Aquatic Science, medicine.disease_cause, Host-Parasite Interactions, Dry weight, Infestation, medicine, Helminths, Animals, Cockle, Mollusca, Ecology, Evolution, Behavior and Systematics, Trophic level, Carbon Isotopes, biology, Nitrogen Isotopes, Ecology, Aquatic animal, biology.organism_classification, Carbon, Female, Trematoda
Abstract: The stable carbon and nitrogen isotopic composition of digenean trematode parasites and their marine mollusc hosts was investigated to describe the potential influence of parasites on their host and its different tissues, and to obtain further insight into their trophic relationships. Four parasite-host systems were studied: Labratrema minimus-Cerastoderma edule, Monorchis parvus-C. edule, Lepocreadiidae parasites-Nassarius reticulatus and Zoogonidae parasites-N. reticulatus. Among the 4 sampling occasions reported here and corresponding to the 4 parasite-host systems, isotopic shifts from pathologic (i.e. linked to disturbances in host metabolism) and mass-balance (i.e. linked to significant differences between host and parasite isotopic signatures) origins were observed only once. Both corresponded to delta 13C measurements of the L. minimus-C. edule system when the infestation load (percentage parasite dry weight compared to total flesh dry weight) was highest (9 to 25%, mean = 16%) over the sampling period. Overall, measurements indicate that digenean trematode parasitism induced low or no shifts in isotopic signatures of C. edule and N. reticulatus tissues. The 2 endoparasites L. minimus and M. parvus appeared to be slightly depleted in 13C compared to C. edule digestive gland and gonads, which were the most parasitized tissues. In contrast, no fractionation or low 15N trophic enrichments occurred in the parasites. These results highly contrast with the classical trophic enrichment reported in prey-predator systems but are in agreement with the scarce literature regarding other parasite-host systems. Our results indicate that (1) digenean trematodes mainly feed on digestive glands (the cockle tissue with which they are mainly associated) with a possible slight preference for lipids, and (2) fractionation due to parasite metabolism should be low due to abbreviated metabolic pathways and/or slight loss of materials through excretion, tegument diffusion and respiration.
Published: 2009

47. Stable isotopes changes in the adductor muscle of diseased bivalve Ruditapes philippinarum

Author: Pierre-Guy Sauriau, Nicolas Savoye, X. de Montaudouin, Philippe Martinez, Cécile Dang, Nathalie Caill-Milly, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Adductor muscle, 0106 biological sciences, Muscle tissue, animal structures, Ruditapes, Aquatic Science, Clam, 010603 evolutionary biology, 01 natural sciences, Calcification, Ruditapes philippinarum, Stable Isotope, medicine, Disease, Mollusca, Ecology, Evolution, Behavior and Systematics, Shellfish, Stable isotopes, Trophic level, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, [SDV.BA.MVSA]Life Sciences [q-bio]/Animal biology/Veterinary medicine and animal Health, Ecology, biology, Conchiolin, 010604 marine biology & hydrobiology, Condition Index, Manila Clam, Anatomy, biology.organism_classification, Bivalvia, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, medicine.anatomical_structure, Aragonite, Posterior Muscle, Adductor muscles, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Abstract: In this article, we show how a disease could bias stable isotope analyzes of trophic networks and propose a strategy in the choice of tissues to be analyzed. In the past few years, a new pathology (brown muscle disease or BMD) affecting the posterior adductor muscle of Ruditapes philippinarum has emerged in Arcachon Bay. BMD induces a necrosis of muscle tissues which become infused by conchiolin and hence calcified. As muscle of mollusks are often used for trophic food webs studies through stable isotopic analyzes, this work investigated the effect of BMD on carbon and nitrogen isotopic ratios of anterior and posterior adductor muscles of clams collected in February and August 2007. Infected clams displayed a lower condition index and a posterior adductor muscle delta C-13 enrichment of 1.2aEuro degrees in February and 0.7aEuro degrees in August. delta N-15 of posterior muscles was however not affected by the disease. Anterior muscle of diseased clams remained healthy and displayed the same isotopic signature as both posterior and anterior muscular tissues of healthy clam. Acidification significantly depleted delta C-13 in posterior muscles of infected clams, suggesting calcification, contrary to anterior muscles of infected clam and to both muscles of healthy clams, where no effect was observed. An X-ray diffractometry analysis confirmed the presence of CaCO3 (aragonite). Trophic food web studies relying on stable isotope ratios should utilize only healthy animals or anterior adductor muscles when expertise in mollusk pathology is lacking.
Published: 2009

48. Mesopelagic organic carbon remineralization in the Kerguelen Plateau region tracked by biogenic particulate Ba

Author: Christophe Monnin, Nicolas Savoye, Damien Cardinal, Urania Christaki, Ingrid Obernosterer, Stephanie Jacquet, Frank Dehairs, Department of Analytical and Environmental Chemistry [Bruxelles], Vrije Universiteit Brussel [Bruxelles] (VUB), Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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]), Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), 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)-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), Royal Museum for Central Africa [Tervuren] (RMCA), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Laboratoire d'océanographie biologique de Banyuls (LOBB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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), Analytical and Environmental Chemistry, Chemistry, 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: 0106 biological sciences, Total organic carbon, chemistry.chemical_classification, 010504 meteorology & atmospheric sciences, Mesopelagic zone, 010604 marine biology & hydrobiology, Iron fertilization, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Particulates, Plankton, Oceanography, 01 natural sciences, Water column, chemistry, 13. Climate action, Particulatebarium, Mesopelagic remineralization, Phytoplankton, Environmental science, Organic matter, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience; We report on the distribution of excess, non-lithogenic particulate barium (Ba), a proxy for twilight-zone remineralization of organic matter (OM), in the Kerguelen Plateau area during the late austral summer of 2005. This study was part of a broader investigation focusing on natural iron fertilization controlling the characteristic and recurrent phytoplankton blooms in the region. The Plateau area contrasted strongly with the off-shelf HNLC area. Plateau stations had quite high excess of Baxs contents (up to 5000 pM) in surface waters (upper 150 m) that coincided with enhanced phytoplankton biomass. However, it had a lower mesopelagic (125–450 m) excess of biogenic Ba contents when compared to the off-shelf stations. Particulate excess Ba in the twilight zone (125–450 m depth layer) proved to be significantly set by the vertical distribution of bacterial activity, with higher particulate Ba contents in situations where significant bacterial activity extended deeper in the water column. These observations are in agreement with the role of excess biogenic particulate Ba as a proxy of twilight-zone OM remineralization. Using a transfer function established during earlier work, we calculated organic carbon remineralization rates and weighed these against other carbon fluxes (primary production, bacterial carbon demand), including carbon export from the 125-m horizon (234Th method). Off-shelf HNLC stations had a larger fraction of the organic carbon production exported and subsequently mineralized in the mesopelagic waters (125–450 m). Plateau stations had a smaller fraction of produced carbon exported, but this fraction appeared less prone to remineralization in the twilight zone and therefore had potential to reach the shallow (not, vert, similar500 m) seafloor or to be exported off-shelf. Differences in trophic structure and in composition of the diatom community would explain the variability in twilight-zone remineralization processes and in transfer efficiency through the mesopelagic zone in the Kerguelen Plateau area.
Published: 2008

49. Mesopelagic carbon remineralization during the European Iron Fertilization Experiment

Author: F.A. Dehairs, Nicolas Savoye, Volker Strass, Damien Cardinal, and Stephanie Jacquet
Subjects: 0106 biological sciences, Total organic carbon, Atmospheric Science, Global and Planetary Change, Remineralisation, 010504 meteorology & atmospheric sciences, Mesopelagic zone, 010604 marine biology & hydrobiology, Iron fertilization, chemistry.chemical_element, 01 natural sciences, Oceanography, Nutrient, Water column, chemistry, Environmental Chemistry, Environmental science, 14. Life underwater, Bloom, Carbon, 0105 earth and related environmental sciences, General Environmental Science
Abstract: [1] The impact of iron fertilization on mesopelagic carbon (C) remineralization was assessed during the European Iron Fertilization Experiment (EIFEX) in the Southern Ocean by following the temporal change of excess particulate barium (also called biogenic or Baxs) in the mesopelagic waters of a mesoscale eddy. Before the iron infusion the site was already sustaining a significant vertical flux of particles leading to organic remineralization in the mesopelagic. Approximately 35 d after the fertilization, mesopelagic Baxs contents provided evidence of changes in surface particulate export and of enhanced and particularly fast remineralization extending down to 1000 m. At the end of the experiment (day 36) both export and remineralization decreased. Organic carbon remineralization took place mainly in the lower part of the mesopelagic zone (500–1000 m) and increased more than 5-fold during EIFEX, reaching values up to 92 ± 15 mg C m−2 d−1. However, such remineralization rates are not particularly high when compared to other values reported for the natural Southern Ocean during summer. Though export and remineralization reached peak values around day 34, remineralization integrated over the 150 to 1000 m layer accounted only for 13 ± 1.4% of the export at 150 m, suggesting that a substantial amount of exported carbon reached deeper in the water column. Compared to natural blooms in high-nutrient low-chlorophyll (HNLC) waters of the Southern Ocean, the Fe-induced bloom during EIFEX resulted in a lower ratio of remineralized organic carbon over exported carbon, similar to what we recently observed for natural Fe-replete conditions prevailing above the Kerguelen Plateau. Unexpected similarities and phase lags of profiles in the mesopelagic between casts sampled inside and outside the fertilized patch during EIFEX indicated that eddy dynamics were a determinant in setting particle patterns on a broad spatial scale exceeding the extent of the fertilization, thereby homogenizing the signals of mesopelagic remineralization.
Published: 2008

50. Primary, new and export production in the NW Pacific subarctic gyre during the vertigo K2 experiments

Author: Willy Baeyens, Marc Elskens, F.A. Dehairs, Ken O. Buesseler, Nicolas Savoye, Nathalie Brion, B. A. S. Van Mooy, and Philip W. Boyd
Subjects: Deep chlorophyll maximum, chemistry.chemical_compound, Oceanography, chemistry, Nitrate, f-ratio, Dissolved organic carbon, Phytoplankton, chemistry.chemical_element, Ammonium, New production, Nitrogen
Abstract: This paper presents results on tracer experiments using 13C and 15N to estimate uptake rates of dissolved inorganic carbon (DIC) and nitrogen (DIN). Experiments were carried out at station K2 (47°N, 161°E) in the NW Pacific subarctic gyre during July-August 2005. Our goal was to investigate relationships between new and export production. New production was inferred from the tracer experiments using the f ratio concept (0-50 m); while export production was assessed with neutrally buoyant sediment traps (NBSTs) and the e ratio concept (at 150 m). During trap deployments, K2 was characterized both by changes in primary production (523-404 mg C m-2d-1), new production (119-67 Mg C m-2d-1), export production (68-24 Mg C m-2d-1) and phytoplankton composition (high to low proportion of diatoms). The data indicate that 17-23% ofprimary production is exportable to deeper layers (f ratio) but only 6-13% collected as a sinking particle flux at 150 m (e ratio). Accordingly, >80% of the carbon fixed by phytoplankton would be mineralized in the upper 50 m (1-f), while < 11% would be within 50-150 m (f-e). DIN uptake flux amounted to 0.5 MM m-2 h-1. which was equivalent to about 95% particulate nitrogen (PN) remineralized and/or grazed within the upper 150 m. Most of the shallow PN remineralization occurred just above the depth of the deep chlorophyll maximum (DCM), where a net ammonium production was measured. Below the DCM, while nitrate uptake rates became negligible because of light limitation, ammonium uptake did continue to be significant. The uptake of ammonium by heterotrophic bacteria was estimated to be 14-17% of the DIN assimilation. Less clear are the consequences of this uptake on the phytoplankton community and biogeochemical processes, e.g. new production. It was suggested that competition for ammonium could select for small cells and may force large diatoms to use nitrate. This implies that under Fe stress as observed here, ammonium uptake is preferred and new production progressively suppressed despite the surplus of nitrate.
Published: 2008

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