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1. Photosynthetic light requirement near the theoretical minimum detected in Arctic microalgae

Author

Clara J. M. Hoppe, Niels Fuchs, Dirk Notz, Philip Anderson, Philipp Assmy, Jørgen Berge, Gunnar Bratbak, Gaël Guillou, Alexandra Kraberg, Aud Larsen, Benoit Lebreton, Eva Leu, Magnus Lucassen, Oliver Müller, Laurent Oziel, Björn Rost, Bernhard Schartmüller, Anders Torstensson, and Jonas Wloka

Subjects
Science
Abstract

Abstract Photosynthesis is one of the most important biological processes on Earth, providing the main source of bioavailable energy, carbon, and oxygen via the use of sunlight. Despite this importance, the minimum light level sustaining photosynthesis and net growth of primary producers in the global ocean is still unknown. Here, we present measurements from the MOSAiC field campaign in the central Arctic Ocean that reveal the resumption of photosynthetic growth and algal biomass buildup under the ice pack at a daily average irradiance of not more than 0.04 ± 0.02 µmol photons m−2 s−1 in late March. This is at least one order of magnitude lower than previous estimates (0.3–5 µmol photons m−2 s−1) and near the theoretical minimum light requirement of photosynthesis (0.01 µmol photons m−2 s−1). Our findings are based on measurements of the temporal development of the under-ice light field and concurrent measurements of both chlorophyll a concentrations and potential net primary production underneath the sea ice at 86 °N. Such low light requirements suggest that euphotic zones where photosynthesis can occur in the world’s oceans may extend further in depth and time, with major implications for global productivity estimates.

Published
2024
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2. Insights on long-term ecosystem changes from stable isotopes in historical squid beaks

Author

Alexey V. Golikov, José C. Xavier, Filipe R. Ceia, José P. Queirós, Paco Bustamante, Bram Couperus, Gaël Guillou, Anna M. Larionova, Rushan M. Sabirov, Christopher J. Somes, and Henk-Jan Hoving

Subjects
Climate change, Food web, Arctic, North atlantic, Cephalopoda, Predator, Ecology, QH540-549.5, Evolution, QH359-425
Abstract

Abstract Background Assessing the historical dynamics of key food web components is crucial to understand how climate change impacts the structure of Arctic marine ecosystems. Most retrospective stable isotopic studies to date assessed potential ecosystem shifts in the Arctic using vertebrate top predators and filter-feeding invertebrates as proxies. However, due to long life histories and specific ecologies, ecosystem shifts are not always detectable when using these taxa. Moreover, there are currently no retrospective stable isotopic studies on various other ecological and taxonomic groups of Arctic biota. To test whether climate-driven shifts in marine ecosystems are reflected in the ecology of short-living mesopredators, ontogenetic changes in stable isotope signatures in chitinous hard body structures were analysed in two abundant squids (Gonatus fabricii and Todarodes sagittatus) from the low latitude Arctic and adjacent waters, collected between 1844 and 2023. Results We detected a temporal increase in diet and habitat-use generalism (= opportunistic choice rather than specialization), trophic position and niche width in G. fabricii from the low latitude Arctic waters. These shifts in trophic ecology matched with the Atlantification of the Arctic ecosystems, which includes increased generalization of food webs and higher primary production, and the influx of boreal species from the North Atlantic as a result of climate change. The Atlantification is especially marked since the late 1990s/early 2000s. The temporal patterns we found in G. fabricii’s trophic ecology were largely unreported in previous Arctic retrospective isotopic ecology studies. Accordingly, T. sagittatus that occur nowadays in the high latitude North Atlantic have a more generalist diet than in the XIXth century. Conclusions Our results suggest that abundant opportunistic mesopredators with short life cycles (such as squids) are good candidates for retrospective ecology studies in the marine ecosystems, and to identify ecosystem shifts driven by climate change. Enhanced generalization of Arctic food webs is reflected in increased diet generalism and niche width in squids, while increased abundance of boreal piscivorous fishes is reflected in squids’ increased trophic position. These findings support opportunism and adaptability in squids, which renders them as potential winners of short-term shifts in Arctic ecosystems.

Published
2024
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3. Trophic niche overlap between sympatric harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) at the southern limit of their European range (Eastern English Channel)

Author

Yann Planque, Jérôme Spitz, Matthieu Authier, Gaël Guillou, Cécile Vincent, and Florence Caurant

Subjects
feeding strategies, foraging ecology, intraindividual variability, marine top predators, pinnipeds, stable isotopes, Ecology, QH540-549.5
Abstract

Abstract Sympatric harbour (Phoca vitulina) and grey seals (Halichoerus grypus) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better understanding of the interactions between these species is critical for conservation efforts. This study aimed to identify the trophic niche overlap between harbour and grey seals at the southern limit of their European range, in the Baie de Somme (BDS, Eastern English Channel, France), where numbers of resident harbour seals and visiting grey seals are increasing exponentially. Dietary overlap was identified from scat contents using hierarchical clustering. Isotopic niche overlap was quantified using δ13C and δ15N isotopic values from whiskers of 18 individuals, by estimating isotopic standard ellipses with a novel hierarchical model developed in a Bayesian framework to consider both intraindividual variability and interindividual variability. Foraging areas of these individuals were identified from telemetry data. The three independent approaches provided converging results, revealing a high trophic niche overlap due to consumption of benthic flatfish. Two diet clusters were dominated by either small or large benthic flatfish; these comprised 85.5% [CI95%: 80.3%–90.2%] of harbour seal scats and 46.8% [35.1%–58.4%] of grey seal scats. The narrower isotopic niche of harbour seals was nested within that of grey seals (58.2% [22.7%–100%] overlap). Grey seals with isotopic values similar to harbour seals foraged in coastal waters close to the BDS alike harbour seals did, suggesting the niche overlap may be due to individual grey seal strategies. Our findings therefore provide the basis for potential competition between both species (foraging on benthic flatfish close to the BDS). We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive interactions and have deleterious effects on harbour seal colonies.

Published
2021
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4. Major Sources of Organic Matter in a Complex Coral Reef Lagoon: Identification from Isotopic Signatures (δ13C and δ15N).

Author

Marine J Briand, Xavier Bonnet, Claire Goiran, Gaël Guillou, and Yves Letourneur

Subjects
Medicine, Science
Abstract

A wide investigation was conducted into the main organic matter (OM) sources supporting coral reef trophic networks in the lagoon of New Caledonia. Sampling included different reef locations (fringing, intermediate and barrier reef), different associated ecosystems (mangroves and seagrass beds) and rivers. In total, 30 taxa of macrophytes, plus pools of particulate and sedimentary OM (POM and SOM) were sampled. Isotopic signatures (C and N) of each OM sources was characterized and the composition of OM pools assessed. In addition, spatial and seasonal variations of reef OM sources were examined. Mangroves isotopic signatures were the most C-depleted (-30.17 ± 0.41 ‰) and seagrass signatures were the most C-enriched (-4.36 ± 0.72 ‰). Trichodesmium spp. had the most N-depleted signatures (-0.14 ± 0.03 ‰) whereas mangroves had the most N-enriched signatures (6.47 ± 0.41 ‰). The composition of POM and SOM varied along a coast-to-barrier reef gradient. River POM and marine POM contributed equally to coastal POM, whereas marine POM represented 90% of the POM on barrier reefs, compared to 10% river POM. The relative importance of river POM, marine POM and mangroves to the SOM pool decreased from fringing to barrier reefs. Conversely, the relative importance of seagrass, Trichodesmium spp. and macroalgae increased along this gradient. Overall, spatial fluctuations in POM and SOM were much greater than in primary producers. Seasonal fluctuations were low for all OM sources. Our results demonstrated that a large variety of OM sources sustain coral reefs, varying in their origin, composition and role and suggest that δ13C was a more useful fingerprint than δ15N in this endeavour. This study also suggested substantial OM exchanges and trophic connections between coral reefs and surrounding ecosystems. Finally, the importance of accounting for environmental characteristics at small temporal and spatial scales before drawing general patterns is highlighted.

Published
2015
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6. Freshwater inflow and responses from estuaries across a climatic gradient: An assessment of northwestern Gulf of Mexico estuaries based on stable isotopes

Author

Danielle A. Marshall, Jennifer Beseres Pollack, Blair Sterba-Boatwright, Gaël Guillou, Benoit Lebreton, Megan K. La Peyre, Terence A. Palmer, School of Renewable Natural Resources, Louisiana State University (LSU), U.S. Geological Survey, Louisiana Cooperative Fish and Wildlife Research Unit, Harte Research Institute for Gulf of Mexico Studies, Texas A&M University [Corpus Christi], LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, geography, Freshwater inflow, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Stable isotope ratio, 010604 marine biology & hydrobiology, Estuary, Aquatic Science, Oceanography, 01 natural sciences, Climatic gradient, 13. Climate action, [SDE]Environmental Sciences, Environmental science, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2021

7. High inter-species variability in elemental composition of the twilight zone fauna varies implications for predators and exploitation by humans

Author

Tiphaine, Chouvelon, Catherine, Munschy, Sandrine, Bruzac, Florence, Caurant, Carine, Churlaud, Sylvette, Crochet, Gaël, Guillou, Aourell, Mauffret, Paula, Méndez-Fernandez, Jasmin, Niol, Teddy, Sireau, Claire, Steinberg, Nathalie, Wessel, and Jérôme, Spitz

Subjects
Food Chain, Seafood, Fishes, Animals, Humans, Mercury, Water Pollutants, Chemical, Environmental Monitoring, Trace Elements
Abstract

While the importance of oceanic micronektonic species in biogeochemical cycles and in the transfer of matter in food webs is globally recognized, specific knowledge on elemental concentrations and their variability within this community is still poorly documented. Here, we report for the first time in the Bay of Biscay, North-East Atlantic, the body composition in various biological parameters and chemical elements of a meso-to bathypelagic micronektonic community. Stable carbon and nitrogen isotope compositions (δ

Published
2021

8. First overview on trophic relationships of the invasive ctenophore Mnemiopsis leidyi in a Mediterranean coastal lagoon (Berre Lagoon, France): benthic–pelagic coupling evidenced by carbon and nitrogen stable isotope composition

Author

Gaël Guillou, Benoit Lebreton, Bruno Belloni, Daniela Bănaru, Loic Guilloux, Guillaume Marchessaux, Mélanie Ourgaud, Mireille Harmelin-Vivien, Delphine Thibault, 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), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-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), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Aquatic Science, 01 natural sciences, Zooplankton, Pelagic ctenophores and cnidarians, Predation, Ecosystem, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Trophic level, Ecology, biology, Mnemiopsis, 010604 marine biology & hydrobiology, Mediterranean lagoon, Pelagic zone, Plankton, biology.organism_classification, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, Benthic zone, [SDE]Environmental Sciences, Animal Science and Zoology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, C and N isotope composition, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

International audience; The ctenophore Mnemiopsis leidyi, ranking among the 100 most damaging bioinvaders in the world, is a major predator of zooplankton, known to alter the biodiversity and functioning of the ecosystems in which it has been introduced. This first survey on the trophic relationships of M. leidyi in a Mediterranean lagoon (Berre, South of France) was performed through stable isotope analyses. Carbon and nitrogen isotope composition was used (1) to determine the types of prey ingested by this ctenophore and (2) the influence of individual size on its isotope composition, and (3) to make assumptions to explore its trophic relationships with the native jellyfish Aurelia sp.. The two gelatinous species ingested mainly (79% to 97% of the diet) planktonic prey (copepods, cirriped nauplii, gastropod larvae and cladocerans), but also preyed upon benthic organisms (mainly harpacticoid copepods and the amphipod Monocorophium insidiosum) in lower proportions (2.5% to 21%). Size-related changes in M. leidyi diet were evidenced with an increase in trophic level and benthic prey consumption in the larger individuals. These two gelatinous organisms probably play an important and underestimated role in the benthic–pelagic​ coupling in coastal lagoons by transferring benthic organic matter to the pelagic food webs.

Published
2021

9. Importance of Serpulid Reef to the Functioning of a Hypersaline Estuary

Author

Natasha Breaux, Gaël Guillou, Jennifer Beseres Pollack, Benoit Lebreton, Terence A. Palmer, Harte Research Institute for Gulf of Mexico Studies, Texas A&M University [Corpus Christi], LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, geography, Biomass (ecology), geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Estuary, 15. Life on land, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, Food web, Habitat destruction, Habitat, Benthic zone, [SDE]Environmental Sciences, Environmental science, 14. Life underwater, Bay, Reef, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS
Abstract

Biogenic reefs provide important ecological functions and services to coastal and marine environments, supplying high levels of biodiversity, providing refuge and foraging habitat, and supporting fisheries. Serpulid reefs are a relatively uncommon habitat in coastal ecosystems globally that provide habitat for a diverse community of organisms, and have become a target for conservation and management efforts due to habitat degradation and loss. Baffin Bay, Texas, USA, is known for exceptionally productive commercial and recreational fisheries that are thought to be supported by Serpulid reef benthic macrofauna, particularly during regular periods of hypersalinity. This study compared the functioning of Serpulid reef habitats with nearby soft sediment areas using quantitative faunal and food web analyses. Serpulid reefs support a unique benthic macrofaunal community with 191 times greater abundance, 97 times greater biomass, and twice the number of species than in soft sediments. In contrast to soft-sediment macrofauna, Serpulid reef macrofaunal abundance and biomass were not correlated with any measured water quality variables. Isotope compositions of both suspension and deposit-feeding macrofauna from both habitats (i.e., Serpulid reefs and soft sediments) were close to organic matter from the sediment, demonstrating connectivity and the importance of primary production in the sediment to both habitat types. Abundant macrofauna inhabiting Serpulid reefs likely serve as an important food source for sport fish and other higher trophic-level fauna, particularly in hypersaline periods when soft-sediment macrobenthic food resources are scarce. Given the substantial loss of Baffin Bay’s Serpulid reef habitat compared to historic levels, conservation actions may be warranted to protect and restore Serpulid habitat and food resources. The results of this study can be used to increase the success of such efforts.

Published
2021

10. Trophic niche overlap between sympatric harbour seals (

Author

Yann, Planque, Jérôme, Spitz, Matthieu, Authier, Gaël, Guillou, Cécile, Vincent, and Florence, Caurant

Subjects
marine top predators, intraindividual variability, pinnipeds, stable isotopes, foraging ecology, feeding strategies, Original Research
Abstract

Sympatric harbour (Phoca vitulina) and grey seals (Halichoerus grypus) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better understanding of the interactions between these species is critical for conservation efforts. This study aimed to identify the trophic niche overlap between harbour and grey seals at the southern limit of their European range, in the Baie de Somme (BDS, Eastern English Channel, France), where numbers of resident harbour seals and visiting grey seals are increasing exponentially. Dietary overlap was identified from scat contents using hierarchical clustering. Isotopic niche overlap was quantified using δ13C and δ15N isotopic values from whiskers of 18 individuals, by estimating isotopic standard ellipses with a novel hierarchical model developed in a Bayesian framework to consider both intraindividual variability and interindividual variability. Foraging areas of these individuals were identified from telemetry data. The three independent approaches provided converging results, revealing a high trophic niche overlap due to consumption of benthic flatfish. Two diet clusters were dominated by either small or large benthic flatfish; these comprised 85.5% [CI95%: 80.3%–90.2%] of harbour seal scats and 46.8% [35.1%–58.4%] of grey seal scats. The narrower isotopic niche of harbour seals was nested within that of grey seals (58.2% [22.7%–100%] overlap). Grey seals with isotopic values similar to harbour seals foraged in coastal waters close to the BDS alike harbour seals did, suggesting the niche overlap may be due to individual grey seal strategies. Our findings therefore provide the basis for potential competition between both species (foraging on benthic flatfish close to the BDS). We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive interactions and have deleterious effects on harbour seal colonies., There is a critical need for a better understanding of interactions between two sympatric seal species, the harbour and grey seals, considered as potential competitors. We identified here the overlap in trophic niches between these two species at the southern limit of their European range, in the Baie de Somme (Eastern English Channel, France). All approaches provided converging results and revealed that foraging on benthic flatfish close to the Baie de Somme is the basis for potential competition between harbour and grey seals. We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive interactions and have deleterious effects on harbour seal colonies.

Published
2020

11. Using GPS tracking and stable multi-isotopes for estimating habitat use and winter range in Palearctic ospreys

Author

Jean-Marie Dominici, Andrea Sforzi, Flavio Monti, Rafel Triay Bagur, Ilham Bentaleb, Aloїs Robert, Gaël Guillou, Olivier Duriez, and Antoni Muñoz Navarro

Subjects
0106 biological sciences, Mediterranean climate, Marsh, Range (biology), Population, Biology, 010603 evolutionary biology, 01 natural sciences, Mediterranean Basin, Pandion haliaetus, Birds, Isotopes, Temperate climate, Animals, Aquatic habitat, Feather isotope ratios, Foraging ecology, Gps tracking, Raptor, Animal Migration, Ecosystem, Seasons, Feathers, education, Ecology, Evolution, Behavior and Systematics, Isotope analysis, geography, education.field_of_study, geography.geographical_feature_category, 010604 marine biology & hydrobiology, Population Ecology–Original Research, Habitat, Physical geography
Abstract

We used both satellite tracking and carbon, nitrogen and sulphur stable isotopic analysis (SIA) to infer wintering ecology and habitat use of the Corsican osprey Pandion haliaetus population. A control sample of feathers from 75 individuals was collected within the osprey’s northern hemisphere breeding range, to assess the SIA variability across habitat types. An experimental set of SIA on feathers of 18 Corsican adults was examined to infer wintering ground locations and habitat types used during the non-breeding period. We calibrated the SIA using GPS/GSM tracks of 12 Mediterranean adults’ movements as wintering site references. We found 50% of individuals were resident and the other half migrated. Ospreys spent the winter at temperate latitudes and showed a high plasticity in habitat selection spread over the Mediterranean basin (marine bays, coastal lagoons/marshland, inland freshwater sites). Complementary to GPS tracking, SIA is, at a broad geographical scale, a reliable method to determine whether ospreys overwinter in a habitat different from that of their breeding area. This study proved that the integration of SIA and GPS/GSM tracking techniques was effective at overcoming the intrinsic limits of each method and achieving greater information for basic ecological studies of migratory birds in aquatic environments. Supplementary Information The online version contains supplementary material available at 10.1007/s00442-021-04855-5.

Published
2020

12. Trophic importance of microphytobenthos and bacteria to meiofauna in soft-bottom intertidal habitats: A combined trophic marker approach

Author

Ragnhild Asmus, Jadwiga Rzeznik-Orignac, Benoit Lebreton, Q. Bernier, Nathalie Niquil, Gaël Guillou, Martin Graeve, Harald Asmus, L.H. van der Heijden, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-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), Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), and Normandie Université (NU)

Subjects
0106 biological sciences, Aquatic Organisms, Geologic Sediments, Nematoda, Meiofauna, Marennes-Oléron Bay, Oceanography, 01 natural sciences, Germany, Microalgae, Sandflats, Stable isotopes, Trophic level, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Carbon Isotopes, biology, Ecology, Stable isotope ratio, Fatty Acids, Food webs, Microphytobenthos, General Medicine, Pollution, Seagrass, Habitat, Bays, Benthic zone, France, Seasons, Bare mudflats, Food Chain, Meiobenthos, Intertidal zone, Aquatic Science, 010603 evolutionary biology, Copepoda, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Animals, Sylt-Rømø Bight, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, 14. Life underwater, Ecosystem, Diatoms, Bacteria, Nitrogen Isotopes, 010604 marine biology & hydrobiology, fungi, Seagrass beds, Feeding Behavior, biology.organism_classification, [SDE.ES]Environmental Sciences/Environmental and Society, Tracheophyta, Compound specific isotope analysis, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract

International audience; Meiofauna can play an important role in the carbon fluxes of soft-bottom coastal habitats. Investigation of their feeding behavior and trophic position remains challenging due to their small size. In this study, we determine and compare the food sources used by nematodes and benthic copepods by using stable isotope compositions, fatty acid profiles and compound specific isotope analyses of fatty acids in the mudflats, seagrass beds and a sandflat of the Marennes-Oléron Bay, France, and the Sylt-Rømø Bight, Germany. Suspended particulate organic matter was much more 13C-depleted than other food sources and meiofauna, highlighting its poor role in the different studied habitats. The very low proportions of vascular plant fatty acid markers in meiofauna demonstrated that these consumers did not rely on this food source, either fresh or detrital, even in seagrass beds. The combined use of stable isotopes and fatty acids emphasized microphytobenthos and benthic bacteria as the major food sources of nematodes and benthic copepods. Compound specific analyses of a bacteria marker confirmed that bacteria mostly used microphytobenthos as a substrate.

Published
2019

13. Primary production and depth drive different trophic structure and functioning of fish assemblages in French marine ecosystems

Author

Gaël Guillou, Matthieu Doray, Daniela Bănaru, Jerome Baudrier, Angélique Jadaud, Paco Bustamante, Jérôme Spitz, Manuel Rouquette, Margaux Denamiel, Pierre Cresson, Tiphaine Chouvelon, Mireille Harmelin-Vivien, Sandrine Serre, François Le Loc'h, Benoit Mialet, Claire Saraux, Coline Lazard, Aourell Mauffret, Marine J. Briand, Nathalie Wessel, Solène Prieur, Yves Verin, Charles-André Timmerman, Laboratoire Ressources halieutiques Boulogne sur mer (LRHBL), Halieutique Manche Mer du Nord (HMMN), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Observatoire pour la Conservation de la Mégafaune Marine (PELAGIS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), 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), Service Valorisation de l'Information pour la gestion Intégrée Et la Surveillance (VIGIES), Dynamiques des Écosystèmes Côtiers (DYNECO), 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), Institut de Recherche pour le Développement (IRD), Laboratoire Biogéochimie des Contaminants Métalliques (LBCM), Biogéochimie et Ecotoxicologie (BE), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire Environnement Ressources Provence Azur Corse (LERPAC), LITTORAL (LITTORAL), Écologie et Modèles pour l'Halieutique (EMH), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ressources halieutiques Manche Mer du nord, IFREMER Centre Manche Mer du Nord, (HMMN), Observatoire PELAGIS UMS 3462 (PELAGIS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Ifremer ODE/VIGIES, 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 BE/LBCM Centre Atlantique, Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ifremer ODE/LER-PAC Centre Méditerranée, Écologie et Modèles pour l'Halieutique (IFREMER EMH), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Future studies, trophodynamics, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, Fish community, Dominance (ecology), Ecosystem, Marine ecosystem, 14. Life underwater, Trophic level, Ecology, ACL, 010604 marine biology & hydrobiology, Food webs, Geology, Pelagic zone, Benthic-pelagic coupling, 15. Life on land, Trophodynamics, Oceanography, 13. Climate action, Benthic zone, food webs, [SDE]Environmental Sciences, benthic-pelagic coupling, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, fish community, Bay
Abstract

International audience; Investigating the drivers of fish assemblage trophic structure is a critical question, in order to better understand ecosystem functioning, predict the effects of perturbations and implement integrated management of exploited marine ecosystems. Ecosystemic surveys enabled the determination of the trophic structure of the fish assemblages in three French marine ecosystems, namely the Eastern English Channel, the Bay of Biscay and the Gulf of Lions, through the simultaneous collection of qualitative (stable isotopes and energy content) and quantitative (biomass) data. In the Bay of Biscay and in the Gulf of Lions, pelagic primary production supported at least 80% of the fish biomass production, and explained the dominance of pelagic species, but with differences resulting from the different productivity. The lower productivity in the oligotrophic Gulf of Lions led to a lower total biomass, energy density as well as the predominance of zooplankton feeders. In contrast, fluxes in the Bay of Biscay were sufficient to support a higher biomass of pelagic piscivores, and of species with higher energy content. In the shallow Eastern English Channel, the respective contributions of pelagic and benthic sources were similar. Bentho-demersal species of higher trophic level dominated this assemblage, because of their ability to exploit both pathways. Results of the present study confirmed that fisheries-focused surveys can be used as efficient platforms to address questions about ecosystem functioning. Here it confirmed the expected differences between ecosystems and the importance of primary production and environment as drivers of fish assemblage structure and functioning. Future studies should nevertheless develop new methods to better assess the paramount role of low trophic level consumers.

Published
2020

14. 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

15. Mercury in blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus) from north-eastern Atlantic: Implication for fishery management

Author

Daniela Bǎnaru, Sebastián Biton-Porsmoguer, Marc Bouchoucha, Mireille Harmelin-Vivien, Gaël Guillou, Charles F. Boudouresque, Ivan Dekeyser, Francoise Marco-Miralles, Benoit Lebreton, 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), Laboratoire Environnement Ressources Provence Azur Corse (LERPAC), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-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), 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), IFREMER - Laboratoire Provence Azur Corse, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Isurus, Food Chain, Food Safety, Fisheries, chemistry.chemical_element, Pelagic sharks, 010501 environmental sciences, Aquatic Science, Biology, Oceanography, 01 natural sciences, Predation, media_common.cataloged_instance, Animals, Humans, Long-line fishery, 14. Life underwater, European union, NE Atlantic, Atlantic Ocean, 0105 earth and related environmental sciences, Trophic level, media_common, Blue shark, 010604 marine biology & hydrobiology, Prionace glauca, Pelagic zone, δ15N, Mercury, biology.organism_classification, Pollution, Mercury (element), Fishery, chemistry, Spain, long-line fishery, Shortfin mako, Sharks, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Water Pollutants, Chemical, Environmental Monitoring
Abstract

International audience; Pelagic sharks (blue shark Prionace glauca and shortfin mako Isurus oxyrinchus) caught by long-line Spanish and Portuguese fleets in the NE Atlantic, were sampled at Vigo fish market (Spain) for total mercury (Hg) analysis. Hg concentration in white muscle increased with size and weight in both species, but at a higher rate in shortfin mako than in the blue shark. No difference was found with sex, year and season. Spatial variation was observed in the blue shark with higher Hg values in the North of the Azorean archipelago, but not in the shortfin mako. These high-level predators are particularly susceptible to bioaccumulate contaminants (Hg) in their tissues (muscle). However, a significant positive relationship between Hg concentration and trophic level (delta N-15) of individuals was observed only in the shortfin mako. Most sharks landed were juveniles which presented Hg concentration lower than the maximum limit allowed by the European Union (1 mg kg(-1) wet weight) for marketing. However, concentrations above this threshold were most recorded in blue sharks larger than 250 cm total length (TL) and in shortfin makos larger than 190 cm TL, raising the question of the commercialization of large-sized individuals.

Published
2018

16. Hg-stable isotope variations in marine top predators of the Western Arctic Ocean

Author

Paul R. Becker, David Amouroux, Gaël Guillou, Jeroen E. Sonke, David Point, Jérémy Masbou, 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 ) -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), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), 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
Atmospheric Science, mercury, 010504 meteorology & atmospheric sciences, Ursus maritimus, 010501 environmental sciences, 01 natural sciences, Marine mammal, Arctic, Geochemistry and Petrology, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, biology.animal, Sea ice, mammals, 14. Life underwater, isotopes, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, biology, Stable isotope ratio, MIF, fungi, δ15N, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [ CHIM.POLY ] Chemical Sciences/Polymers, [CHIM.POLY]Chemical Sciences/Polymers, 13. Climate action, Space and Planetary Science, Bioaccumulation, Environmental chemistry, [ CHIM.MATE ] Chemical Sciences/Material chemistry, [ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistry, Beluga Whale, Environmental science, [ CHIM.ANAL ] Chemical Sciences/Analytical chemistry, geographic locations
Abstract

Recent studies on mercury (Hg)-stable isotopes in Alaskan seabird eggs and ringed seal livers illustrated the control of sea ice cover on marine methyl-Hg photochemistry. Here, complementary marine mammal tissues have been analyzed to document variations in Hg-, carbon (C)-, and nitrogen (N)-stable isotope compositions of Arctic marine food webs. Hg-stable isotope ratios were measured in liver samples of 55 beluga whales (Delphinapterus leucas) and 15 polar bears (Ursus maritimus) collected since 1990. Large variations in delta Hg-202 (approximate to 2.1 parts per thousand) and Delta Hg-199 (approximate to 1.7 parts per thousand) are observed between species and within species stocks covering the Gulf of Alaska-Bering Sea-Arctic Ocean regions. Polar bears, mainly feeding on ringed seal (delta N-15 shift of 4.2 parts per thousand), show identical liver Delta Hg-199 of 0.5 parts per thousand, confirming the absence of metabolic mass-independent fractionation, and 0.33 +/- 0.11 parts per thousand enrichment in heavy Hg isotopes. Beluga whale liver total Hg concentrations increase with age, reflecting lifetime bioaccumulation, while Hg speciation shifts to inorganic Hg with age as a result of hepatic methyl-Hg breakdown. Delta Hg-200 variations in biota show a small, 0.1 parts per thousand decrease from North Pacific Ocean to Arctic Ocean habitats, suggesting atmospheric Hg deposition to be important in the Pacific and terrestrial Hg inputs to dominate in the Arctic Ocean. Similar to seabird eggs, a consistent south to north gradient in Delta Hg-199 baseline is seen in mammal liver tissues, confirming sea ice cover as a control factor on marine Hg photoreduction and Delta Hg-199. Arctic Ocean beluga whales have near zero Delta Hg-199, indicating that terrestrial Hg and in-situ-produced methyl-Hg are not measurably photoreduced in the Arctic Ocean before entering the marine food web.

Published
2018

17. Trace elements in a Mediterranean scorpaenid fish: Bioaccumulation processes and spatial variations

Author

Paco Bustamante, Hugo Bourgogne, Sandrine Ruitton, Benoit Lebreton, Gaël Guillou, Carine Churlaud, Mélanie Ourgaud, Mireille Harmelin-Vivien, 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), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-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), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines ( LMGEM ), Centre National de la Recherche Scientifique ( CNRS ) -Université de la Méditerranée - Aix-Marseille 2, LIttoral ENvironnement et Sociétés - UMR 7266 ( LIENSs ), and Université de La Rochelle ( ULR ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
010504 meteorology & atmospheric sciences, Coastal fish, 010501 environmental sciences, Aquatic Science, 01 natural sciences, Mediterranean sea, Scorpaena, Mediterranean Sea, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Trophic level, [ SDE.BE ] Environmental Sciences/Biodiversity and Ecology, Trace elements, biology, Chemistry, Stable isotope ratio, Ecology, Trace element, Geology, Scorpaena porcus, biology.organism_classification, Bioaccumulation, Oceanography, Seagrass, Environmental chemistry, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; The black scorpionfish Scorpaena porcus, a carnivorous sedentary species, was studied as an indicator of local trace element (TE) contamination of coastal fish species in the northwestern Mediterranean Sea. Fish were collected in seagrass meadows in winter 2012 at four sampling sites: three were located near Marseille, a highly urbanized and industrial area that is subjected to various types of contaminant inputs, and one was located near Hyères, a less urbanized area. Size, sex, age and diet of fish were determined before stable isotope and TE analyses. C and N isotopic compositions and concentrations of nine TEs (As, Ba, Cd, Cu, Cr, T-Hg, Ni, Pb, and Zn) were determined in dorsal white muscle. Most TEs did not bioaccumulate in S. porcus, as no increase in TE concentrations with increasing size, age or trophic level of fish was evident. Total mercury (T-Hg) was the only element to bioaccumulate and biomagnify, displaying strong positive correlations of its concentration with age (r = 0.88, p < 0.01), length (r = 0.84, p < 0.01) and δ 15 N value (r = 0.68, p < 0.01). Compared with the reference site, higher concentrations of As, Ba, Cd, T-Hg, Pb, and Zn were recorded in fish collected at one or all of the Marseille site. In contrast, no difference was observed for Cr, Cu, and Ni concentrations with site. Spatial differences in TE concentrations in S. porcus were related to differences in isotopic composition and to the primary environmental characteristics and human activities prevailing at each site. Concentrations of Cd, T-Hg and Pb in fish muscle (priority substances for monitoring) were all below the maximum permitted European values.

Published
2018

18. Methods of lipid-normalization for multi-tissue stable isotope analyses in tropical tuna

Author

Benoit Lebreton, Maxime Degroote, Edwin Fouché, Nathalie Bodin, Fany Sardenne, Stephanie Hollanda, Gaël Guillou, and Frédéric Ménard

Subjects
0106 biological sciences, Normalization (statistics), Skipjack tuna, δ13C, biology, Chemistry, Stable isotope ratio, 010604 marine biology & hydrobiology, Organic Chemistry, Extraction (chemistry), biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Isotopes of nitrogen, Analytical Chemistry, Isotopes of carbon, Environmental chemistry, 14. Life underwater, Biological system, Tuna, Spectroscopy
Abstract

RATIONALE: The bias associated with lipid contents in fish tissues is a recalcitrant topic for trophic studies using stable isotopes. Lipids are depleted in the heavy carbon isotope (13C) and the lipid content varies considerably among species, tissues and in both time and space. We have applied and assessed different correction methods for tropical tuna tissues. METHODS:We tested two types of normalization methods to deal with variable lipid content in liver, gonads, and white and red muscles of yellowfin, bigeye and skipjack tuna: a chemical extraction using dichloromethane and a mathematical correction based on three modeling approaches (linear, non-linear and mass balance models). We measured isotopic ratios of bulk and lipid-free tissues and assessed the predictive ability of the correction models with the lipid-free measurements. The parameters of the models were estimated from our dataset and from results from published studies on other species. RESULTS: Comparison between bulk, lipid-free and lipid-corrected isotopic ratios demonstrated that (1) chemical extraction using dichloromethane did not affect δ15N values; (2) the change in δ13C values after extraction was tissuespecific; (3) lipid-normalization models using published parameter estimates failed to predict lipid-corrected δ13C values; and (4) linear and non-linear models using parameters estimated for each tissue from our dataset provided accurate δ13C predictions for all tissues, and mass balance model for white muscle only. CONCLUSIONS: Models using published estimates for parameters from other species cannot be used. Based on a range of lipid content that do not exceed 45%, we recommend the linear model to correct the bulk δ13C values in the investigated tissues but the parameters have to be estimated from a proportion of the original data for which chemical extraction is required and the isotopic values of bulk and lipid-free tissues are measured.

Published
2015

19. 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

20. Pathways of organic matter in an estuarine mangrove trophic network assessed by carbon and nitrogen stable isotopes

Author

Marine J. Briand, Yves Letourneur, Gaël Guillou, Institut de sciences exactes et appliquées (ISEA), and Université de la Nouvelle-Calédonie (UNC)

Subjects
0106 biological sciences, chemistry.chemical_classification, biology, Ecology, 010604 marine biology & hydrobiology, [SDV]Life Sciences [q-bio], 15. Life on land, Aquatic Science, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Food web, Food chain, chemistry, Avicennia marina, [SDE]Environmental Sciences, Environmental science, Sedimentary organic matter, Organic matter, Ecosystem, 14. Life underwater, Mangrove, Trophic level
Abstract

Carbon and nitrogen stable isotopes were used to describe an estuarine mangrove food web in New Caledonia, SW Pacific. Isotopic values were measured for all components of the ecosystem, from various organic matter (OM) sources to predators. Primary producers showed δ13C values from −32.29‰ (Bruguiera gymnorhiza) to −24.67‰ (mouth particulate organic matter), whereas δ15N values ranged from 1.48‰ (Avicennia marina) to 10.17‰ (Eichomia crassipes). Two potential organic matter sources, i.e. the mangrove species and E. crassipes, appeared not to be directly used by consumers although were indirectly entering the food web through particulate and sedimentary organic matter pools (POM and SOM). Overall, invertebrates showed C-depleted and N-depleted values compared with fish, highlighting their lower trophic level. The highest trophic levels in this estuarine mangrove were represented by carangids (δ15N of 11.24‰ for Caranx sp. and 10.81‰ for Carangoides fulvoguttatus) and gerrids (δ15N of 10.42‰ for Gerres filamentosus). Two main pathways of organic matter were identified from sources of OM to end-members, i.e. from estuarine POM and SOM toward gerrids and from marine POM towards carangids. The food chain comprised three or four trophic levels, depending on the pathway of organic matter. The position of some consumer species within the reconstructed food web might imply that an important source of organic matter was probably missing, i.e. microphytobenthos. Despite an obvious connection, the role of river inputs as potential drivers of mangrove food web dynamics appeared important only during the wet season.

Published
2017

21. 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

22. Trophic shift in young-of-the-year Mugilidae during salt-marsh colonization

Author

Benoit Lebreton, Pierre Richard, Gaël Guillou, and Gérard F. Blanchard

Subjects
geography, geography.geographical_feature_category, Ecology, Consumer, Pelagic zone, Aquatic Science, Biology, Fish measurement, biology.organism_classification, Predation, Benthic zone, Salt marsh, Golden grey mullet, Ecology, Evolution, Behavior and Systematics, Trophic level
Abstract

This study investigated the trophic shift of young-of-the-year (YOY) thinlip grey mullet Liza ramada and golden grey mullet Liza aurata during their recruitment in a salt marsh located on the European Atlantic Ocean coast. Stable-isotope signatures (δ(13) C and δ(15) N) of the fishes followed a pattern, having enrichments in (13) C and (15) N with increasing fork length (LF ): δ(13) C in fishes 30 mm δ(13) C ranged from -15.8 to -12.7‰, closer to the level in salt-marsh food resources. Large differences between the δ(15) N values of mugilids and those of food sources (6·0‰ on average) showed that YOY are secondary consumers, similar to older individuals, when feeding in the salt marsh. YOY mugilids shift from browsing on pelagic prey to grazing on benthic resources from the salt marsh before reaching 30 mm LF. The results highlight the role of European salt marshes as nurseries for juvenile mugilids.

Published
2013

23. Trophic niches of sympatric tropical tuna in the Western Indian Ocean inferred by stable isotopes and neutral fatty acids

Author

Aurélien Amiel, Heidi Pethybridge, Frédéric Ménard, Stephanie Hollanda, Nathalie Bodin, Fany Sardenne, Emmanuel Chassot, Edwin Fouché, Gaël Guillou, Maxime Degroote, Benoit Lebreton, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Prévention et promotion de la cancérogénèse par les aliments (ToxAlim-PPCA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Seychelles Fishing Authority (SFA) (SFA), Université des Seychelles, CISRO Oceans and Atmosphere Flagship, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-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)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université de Toulouse (UT)-Université de Toulouse (UT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Ecole d'Ingénieurs de Purpan (INP - PURPAN), and Sardenne, Fany

Subjects
0106 biological sciences, monoene fats, Yellowfin tuna, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, mozambique channel, food-web, thunnus-albacares, 14. Life underwater, foraging ecology, ComputingMilieux_MISCELLANEOUS, Trophic level, Isotope analysis, Ecological niche, biology, Ecology, Stable isotope ratio, 010604 marine biology & hydrobiology, Niche differentiation, yellowfin tuna, salmon salmo-salar, Geology, biology.organism_classification, Food web, pacific-ocean, top predators, diet, [SDE]Environmental Sciences, Tuna
Abstract

International audience; This study examined the trophic ecology of three sympatric tropical tuna species (bigeye BET, skipjack SKJ, and yellowfin YFT) sampled in the Western Indian Ocean throughout 2013. Specifically we explored inter-specific resource partitioning and ontogenetic variability using neutral fatty acids and stable isotope analysis of liver and muscle from small (100 cm FL) tuna collected in mixed schools at the surface by purse-seine. Both biochemical tracers were used to calculate trophic niche indices that collectively revealed high potential for resource overlap, especially among small tuna. Resource overlap appeared strongest between BET and YFT, with SKJ tissues having high carbon isotope (delta C-13) values (-17 +/- 0.3 parts per thousand), lower nitrogen isotope (delta N-15) values (11.4 +/- 0.6 parts per thousand), and higher relative proportion of poly-unsaturated fatty acids (PUFA) than the two other species, indicating a different diet. Size was found to be a strong predictor for most biochemical tracers in the three species with delta C-13, delta N-15 and total lipid content in the liver. In the larger species (YFT and BET), proportions of mono-unsaturated fatty acids typically increased with size, while quantities of PUFA decreased. In addition to ontogenetic variability, trophic markers were shown to vary between sampling area and season: higher lipid reserves and delta N-15 values, and lower delta C-13 values occurred during monsoon periods around Seychelles than in the Mozambique Channel (parted from about 1500 km). Our multi-tracer approach reveals the magnitude of potential competitive interactions in mixed tropical tuna schools at both small and large sizes and demonstrates that ontogenetic niche differentiation acts as a major factor of coexistence in tropical tuna

Published
2016

24. Complex food webs in highly diversified coral reefs: Insights from δ13C and δ15N stable isotopes

Author

Xavier Bonnet, Marine J. Briand, Gaël Guillou, Yves Letourneur, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire LIVE, Université de la Nouvelle Calédonie (UNC), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), and LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs)

Subjects
0106 biological sciences, Organic matter sources, 010603 evolutionary biology, 01 natural sciences, Predatory fish, New Caledonia, 14. Life underwater, Reef, Ecology, Evolution, Behavior and Systematics, Trophic level, geography, geography.geographical_feature_category, Ecology, biology, 010604 marine biology & hydrobiology, Pelagic zone, Coral reef, Isotopic ratios, biology.organism_classification, Food web, Fishery, Predators, Seagrass, Benthic zone, [SDE]Environmental Sciences, Trophic networks, Consumers
Abstract

International audience; We studied the trophic network architecture of the coral reef ecosystem of the New Caledonian lagoon. To encompass the main tropic levels, we assayed carbon and nitrogen stable isotopes in various organic matter sources, intermediate consumers (invertebrates and fish), and 19 species of predatory fish (total of 1229 samples). At each level, wide range of variations for δ13C and δ15N suggested multiple sources for the OM, and complex trophic relationships among the different organisms. Despite this complexity, four trophic structures were identified. 1) The predominant reef benthic food web (R-BFW) based on the OM produced by algal turf supplies most of intermediate consumers and all anguilliform fish studied. 2) The sedimentary benthic food web (S-BFW), and 3) the lagoon pelagic food web (L-PFW), respectively based on sedimentary OM (SOM) and particulate OM (POM) involve a wide range of organisms and represent complementary food webs for most anguilliform fish. 4) Finally, the detrital benthic food web (D-BFB) where the OM issued from seagrass is indirectly utilised by reef consumers plays a secondary role. Anguilliform fish are widespread sedentary predators that live in various habitats; the species sampled were respectively associated with the three main trophic structures identified, depending on their diet and habitat. This study reveals several major structures that are inter-connected to form an overall complex trophic network in the coral reefs.

Published
2016

25. Seasonal variation of harbor seal's diet from the Wadden Sea in relation to prey availability

Author

Benoit Lebreton, Ursula Siebert, Harald Asmus, Krishna Das, Gaël Guillou, Camille de la Vega, Ragnhild Asmus, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover Foundation (TiHo), and Laboratory of oceanology — MARE center, Université de Liège

Subjects
0106 biological sciences, Male, Composite Particles, Seasonal variation, lcsh:Medicine, Predation, 01 natural sciences, Wadden Sea, Isotopes, Harbor seal, Biomass, Animal Anatomy, lcsh:Science, Stable isotopes, Biomass (ecology), Carbon Isotopes, Multidisciplinary, biology, Ecology, Geography, Physics, Trophic Interactions, Spring, Community Ecology, Benthic zone, Physical Sciences, [SDE]Environmental Sciences, Female, Seasons, North Sea, Research Article, Atoms, Food Chain, Summer, Foraging, Phoca, 010603 evolutionary biology, Marine mammal, Species Specificity, [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology, medicine, Animal Physiology, Animals, 14. Life underwater, Particle Physics, Analysis of Variance, Nitrogen Isotopes, 010604 marine biology & hydrobiology, lcsh:R, Ecology and Environmental Sciences, Winter, Biology and Life Sciences, Pelagic zone, Seasonality, biology.organism_classification, medicine.disease, Diet, Vibrissae, Predatory Behavior, Earth Sciences, lcsh:Q, Zoology
Abstract

International audience; The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight.

Published
2016

26. Origin, composition and quality of suspended particulate organic matter in relation to freshwater inflow in a South Texas estuary

Author

Jennifer Beseres Pollack, Terence A. Palmer, Benoit Lebreton, Paul A. Montagna, Gaël Guillou, Brittany N. Blomberg, L. G. Adams, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Harte Research Institute for Gulf of Mexico Studies, Texas A&M University [Corpus Christi], and Department of Life Sciences, Texas A&M University – Corpus Christi

Subjects
0106 biological sciences, Freshwater inflow, 010504 meteorology & atmospheric sciences, Chlorophyll a, Aquatic Science, Suspended particulate organic matter, Oceanography, 01 natural sciences, Phytoplankton, Organic matter, 14. Life underwater, Stable isotope ratio, 0105 earth and related environmental sciences, chemistry.chemical_classification, Hydrology, Total organic carbon, geography, Gulf of Mexico, geography.geographical_feature_category, Detritus, Texas estuary, 010604 marine biology & hydrobiology, Estuary, 15. Life on land, 6. Clean water, chemistry, 13. Climate action, Benthic zone, Salt marsh, [SDE]Environmental Sciences, Environmental science
Abstract

International audience; South Texas has a semi-arid climate with a large interannual variability of freshwater inflows. This study sought to define how changes in freshwater inflow affect the composition, quantity and quality of suspended particulate organic matter (SPOM) in a South Texas estuary: the Mission-Aransas estuary. The study was implemented 1.5 months after a large rain event in September 2010 and continued for 10 months of drought conditions. The composition of SPOM originating from rivers, the Gulf of Mexico and the estuary were determined using stable isotopes (δ 13 C, δ 15 N and δ 34 S). The quantity and quality of SPOM were assessed using organic carbon content, chlorophyll a concentrations and C/chl a ratios. Our results demonstrated that autochthonous phytoplankton was the dominant component of SPOM in the Mission-Aransas estuary during droughts. Benthic organic matter from local primary producers (i.e., seagrass, salt marsh plants, benthic microalgae) did not influence SPOM composition, either as fresh material or as detritus. A comparison with a positive estuary (i.e., Sabine-Neches estuary, TX) indicates that decreases in freshwater inflow may lead to decreases of terrestrial organic matter inputs and to increase the ratio of autochtonous phytoplanktonic material in SPOM. Highlights-Phytoplankton dominate particulate organic matter in the Mission-Aransas estuary.-Benthic organic matter does not influence particulate organic matter composition.-Organic matter drained by rivers during minor rain events is of very poor quality.

Published
2016

27. Trophic ecology of mullets during their spring migration in a European saltmarsh: A stable isotope study

Author

Benoit Lebreton, Gaël Guillou, Pierre Richard, Gérard F. Blanchard, and Emmanuel P. Parlier

Subjects
education.field_of_study, biology, Ecology, Meiobenthos, Population, Aquatic Science, Catch per unit effort, Oceanography, biology.organism_classification, Mullet, Food web, education, Bay, Isotope analysis, Trophic level
Abstract

Mullet populations are abundant in littoral waters throughout the world and play a significant role in organic matter fluxes. Mullets are opportunistic feeders: adults have frequently been shown to feed on primary producers (e.g. fresh or detrital plant material, microphytobenthos) but they may also feed on meiofauna. The population structure and stomach contents of mullets that colonize saltmarsh creeks in Aiguillon Bay (French Atlantic coast) were studied to determine if they use saltmarshes as a feeding ground in spring. Stable isotope analyses were carried out on mullets sampled to assess their diet during their spring migration. The mullet population was primarily composed of young-of-the-year (G0), 1 year-old (G1) of both Liza ramada and Liza aurata species and 3 year-old or older (G3+) L. ramada individuals. G0 and G3+ population densities increased during the spring period: catch per unit effort (CPUE) increased from 0.22 to 1.49 ind min −1 for the G0 age group; but stomach content analyses revealed that only G1 and G3+ feed in the saltmarsh. Isotopic signatures of G1 (spring: δ 13 C: −14.8‰, δ 15 N: 14.1‰) and G3+ mullets (spring: δ 13 C: −16.9‰, δ 15 N: 13.8‰) indicate that mullet growth is supported largely by primary consumers, such as benthic meiofauna or small macrofauna. Mullets are thus positioned at a much higher trophic level than true primary consumers.

Published
2011

28. 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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29. Relative contribution of natural productivity and compound feed to tissue growth in blue shrimp (Litopenaeus stylirostris) reared in biofloc: Assessment by C and N stable isotope ratios and effect on key digestive enzymes

Author

Emilie Cardona, Pierre Richard, Gaël Guillou, Denis Saulnier, Liet Chim, Claire Geffroy, Bénédicte Lorgeoux, Yannick Gueguen, Unité de recherche Lagons, Ecosystèmes et Aquaculture Durable en Nouvelle Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre Océanologique du Pacifique (COP), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Interactions Hôtes-Pathogènes-Environnements (IHPE), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Perpignan Via Domitia (UPVD)

Subjects
animal structures, Biomass, Aquatic Science, Biology, 03 medical and health sciences, Fish meal, Digestive enzyme activities, 14. Life underwater, Food science, Soy protein, 030304 developmental biology, 2. Zero hunger, chemistry.chemical_classification, 0303 health sciences, Stable isotope ratio, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], fungi, Digestive enzyme mRNA level, 04 agricultural and veterinary sciences, Litopenaeus stylirostris, Stable isotope, Shrimp, Fishery, Enzyme, Productivity (ecology), chemistry, 040102 fisheries, 0401 agriculture, forestry, and fisheries, Shrimps, Biofloc
Abstract

The aim of this study was to assess the relative contribution of natural productivity and compound food to the growth of the juvenile blue shrimp Litopenaeus stylirostris reared in a biofloc system. Two experiments were carried out based on the same protocol with three treatments: clear water with experimental diet (CW), biofloc with experimental diet (BF) and biofloc unfed (BU). Shrimp survival was significantly higher in biofloc rearing than in CW rearing. The contribution of the biofloc to shrimp diet was estimated through measurement of carbon and nitrogen stable isotope ratios in shrimp and food sources. Different isotopic compositions between feeds were obtained by feeding natural productivity with a mixture rich in fish meal and the shrimps with a pellet containing a high level of soy protein concentrate. Using a two source one-isotope mixing model, we found that the natural productivity of the biofloc system contributed to shrimp growth at a level of 39.8% and 36.9%, for C and N, respectively. The natural food consumed by the shrimps reared in the biofloc system resulted in higher gene expression (mRNA transcript abundance) and activities of two digestive enzymes in their digestive gland: α-amylase and trypsin. The growth of shrimp biomass reared in biofloc was, on average, 4.4 times that of those grown in clear water. Our results confirmed the best survival and promoted growth of shrimps using biofloc technology and highlighted the key role of the biofloc in the nutrition of rearing shrimps. Statement of relevance In this study, we have applied an original protocol to determine the respective contribution of natural productivity and artificial feeds on the alimentation of the juvenile blue shrimp L. stylirostris reared in biofloc system by using C and N natural stable isotope analysis. Moreover, we have compared, in shrimp digestive gland, the α-amylase and trypsin enzyme activities at biochemical and molecular levels for two different shrimp rearing systems, biofloc and clear water. In our knowledge, the use of molecular tool to study the influence of biofloc consumption on digest process of shrimp was never carried out. We think that our research is new and important to increase knowledge on biofloc topic.

Published
2015

30. Methods of lipid-normalization for multi-tissue stable isotope analyses in tropical tuna

Author

Fany, Sardenne, Frédéric, Ménard, Maxime, Degroote, Edwin, Fouché, Gaël, Guillou, Benoit, Lebreton, Stephanie J, Hollanda, and Nathalie, Bodin

Subjects
Fish Proteins, Male, Carbon Isotopes, Tropical Climate, Nitrogen Isotopes, Tuna, Chemical Fractionation, Models, Theoretical, Lipids, Mass Spectrometry, Liver, Animals, Female, Muscle, Skeletal, Indian Ocean
Abstract

The bias associated with lipid contents in fish tissues is a recalcitrant topic for trophic studies using stable isotopes. Lipids are depleted in the heavy carbon isotope ((13)C) and the lipid content varies considerably among species, tissues and in both time and space. We have applied and assessed different correction methods for tropical tuna tissues.We tested two types of normalization methods to deal with variable lipid content in liver, gonads, and white and red muscles of yellowfin, bigeye and skipjack tuna: a chemical extraction using dichloromethane and a mathematical correction based on three modeling approaches (linear, non-linear and mass balance models). We measured isotopic ratios of bulk and lipid-free tissues and assessed the predictive ability of the correction models with the lipid-free measurements. The parameters of the models were estimated from our dataset and from results from published studies on other species.Comparison between bulk, lipid-free and lipid-corrected isotopic ratios demonstrated that (1) chemical extraction using dichloromethane did not affect δ(15)N values; (2) the change in δ(13)C values after extraction was tissue-specific; (3) lipid-normalization models using published parameter estimates failed to predict lipid-corrected δ(13)C values; and (4) linear and non-linear models using parameters estimated for each tissue from our dataset provided accurate δ(13)C predictions for all tissues, and mass balance model for white muscle only.Models using published estimates for parameters from other species cannot be used. Based on a range of lipid content that do not exceed 45%, we recommend the linear model to correct the bulk δ(13)C values in the investigated tissues but the parameters have to be estimated from a proportion of the original data for which chemical extraction is required and the isotopic values of bulk and lipid-free tissues are measured.

Published
2014

31. Trophic ecology of European sardine Sardina pilchardus and European anchovy Engraulis encrasicolus in the Bay of Biscay (north-east Atlantic) inferred from δ13C and δ15N values of fish and identified mesozooplanktonic organisms

Author

Françoise Mornet, Christine Dupuy, Laurie Violamer, Sébastien Lefebvre, Paco Bustamante, Gaël Guillou, Tiphaine Chouvelon, Alexis Chappuis, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-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 Ressources Halieutiques (LRH), 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), and 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])

Subjects
Aquatic Science, Oceanography, Spatial variability, Pelagic fish, plankton preservation, Plankton preservation, Engraulis, pelagic fish, European anchovy, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Trophic level, trophic interactions, plankton delipidation, biology, Ecology, Sardine, Pelagic zone, Plankton, biology.organism_classification, Isotopic mixing model, Fishery, isotopic mixing model, spatial variability, Trophic interactions, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, Acartia, Bay, Plankton delipidation
Abstract

International audience; European sardine (Sardina pilchardus) and European anchovy (Engraulis encrasicolus) are two species of economical and ecological significance in the Bay of Biscay (north-east Atlantic). However, the trophic ecology of both species is still poorly known in the area, and more generally, few studies have considered the potential trophic overlap between sardines and anchovies worldwide. This study aims to highlight the trophic links between the mesozooplankton and adults of these two pelagic fish in the Bay of Biscay, through carbon and nitrogen stable isotopes analysis (SIA). Mesozooplankton and individuals of sardines and anchovies were collected during one season (spring 2010), over spatially contrasted stations within the study area. First, the potential effect of preservation (ethanol vs. freezing) and of delipidation (by cyclohexane) on mesozooplankton δ13C and δ15N values was assessed. Results demonstrated the necessity to correct for the preservation effect and for lipid contents in mesozooplankton for further analyses of sardines' and anchovies' diet through SIA. Next, this study highlighted the interest of working on identified mesozooplanktonic organisms instead of undetermined assemblages when unravelling food sources of planktivorous fish using stable isotopes. The inter-specific variability of isotope values within a planktonic assemblage was effectively high, probably depending on the various feeding behaviours that can occur among mesozooplankton species. Intra-specific variability was also significant and related to the spatial variations of baseline signatures in the area. To investigate the foraging areas and potential diet overlap of S. pilchardus and E. encrasicolus, mixing models (SIAR) were applied. Both fish species appeared to feed mainly in the neritic waters of the Bay of Biscay in spring and to select mainly small- to medium-sized copepods (e.g. Acartia sp., Temora sp.). However, E. encrasicolus showed a greater trophic plasticity by foraging more offshore and on a wider range of prey sizes, while S. pilchardus seemed more limited to coastal areas and the mesozooplanktonic species of these waters for feeding.

Published
2014

32. Spatial variability of metallic and organic contamination of anguilliform fish in New Caledonia

Author

Paco Bustamante, Thomas Fauvel, Xavier Bonnet, Marine J. Briand, François Brischoux, Gaël Guillou, Emmanuel Wafo, Yves Letourneur, Laboratoire Insulaire du Vivant et de l'Environnement (LIVE), Université de la Nouvelle-Calédonie (UNC), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Pollution, Health, Toxicology and Mutagenesis, media_common.quotation_subject, Biodiversity, 010501 environmental sciences, 01 natural sciences, Mining, Predatory fish, New Caledonia, Environmental Chemistry, Animals, 14. Life underwater, PCBs, Organic Chemicals, Pesticides, POPs, 0105 earth and related environmental sciences, media_common, Pollutant, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, Trace element, Fishes, carnivorous fish, General Medicine, Coral reef, Contamination, 6. Clean water, Trace Elements, Fishery, Oceanography, 13. Climate action, Metals, Environmental science, Spatial variability, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, coral reefs, SW Pacific Ocean, Water Pollutants, Chemical, Environmental Monitoring
Abstract

International audience; New Caledonia is one of the main hot spots of biodiversity on the planet. Large amounts of contaminants are discharged into the lagoon as a result of increasing anthropogenic activities such as intense mining, urbanization and industrialization. Concentrations of 14 trace elements and 26 persistent organic pollutants (POPs: PCBs and pesticides) were measured in the muscles of two anguilliform fish species, over a coast to barrier reef gradient in two lagoon areas differently exposed to anthropic disturbances. This study emphasizes the high trace element contamination status of anguilliform fish and also highlights slight but perceptible organic pollution. The contamination extends throughout the lagoon, from coast to barrier reef, even in areas remote from emission points. High levels of trace elements, especially those linked to mining activities (i.e. Co, Cr, Fe, Mn and Ni), were detected in coastal sites. Furthermore the large dispersion of most POPs throughout the entire lagoon poses the question of their potential toxicity on marine organisms from numerous habitats. Our results underline the need for long term monitoring of various contaminants over large spatial and time scales.

Published
2013

33. Macroalgae delta N-15 values in well-mixed estuaries: Indicator of anthropogenic nitrogen input or macroalgae metabolism?

Author

Mélanie Raimonet, Gaël Guillou, Françoise Mornet, Pierre Richard, Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, 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), Laboratoire Ressources Halieutiques (LRH), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris), LIttoral ENvironnement et Sociétés (LIENSs), and La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, nitrogen isotopes, Fucus serratus, Fucus vesiculosus, 010501 environmental sciences, Aquatic Science, Biology, Oceanography, 01 natural sciences, chemistry.chemical_compound, Nitrate, land-sea continuum, nitrate, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, primary producers, Ecology, Stable isotope ratio, 010604 marine biology & hydrobiology, Estuary, δ15N, 15. Life on land, biology.organism_classification, 6. Clean water, Isotopes of nitrogen, indicators, ammonium, chemistry, 13. Climate action, Environmental chemistry, Bioindicator
Abstract

Although nitrogen stable isotope ratio (delta N-15) in macroalgae is widely used as a bioindicator of anthropogenic nitrogen inputs to the coastal zone, recent studies suggest the possible role of macroalgae metabolism in delta N-15 variability. Simultaneous determinations of delta N-15 of dissolved inorganic nitrogen (DIN) along the land sea continuum, inter-species variability of delta N-15 and its sensitivity to environmental factors are necessary to confirm the efficiency of macroalgae delta N-15 in monitoring nitrogen origin in mixed-use watersheds. In this study, delta N-15 of annual and perennial macroalgae (Ulva sp., Enterommpha sp., Fucus vesiculosus and Fucus serratus) are compared to delta N-15-DIN along the Charente Estuary, after characterizing delta N-15 of the three main DIN sources (i.e. cultivated area, pasture, sewage treatment plant outlet). During late winter and spring, when human activities produce high DIN inputs, DIN sources exhibit distinct delta N-15 signals in nitrate (NO3-) and ammonium (NH4+): cultivated area (+6.5 +/- 0.6 parts per thousand and +9.0 +/- 11.0 parts per thousand), pasture (+9.2 +/- 1.8 parts per thousand and +12.4 parts per thousand) and sewage treatment plant discharge (+16.9 +/- 8.7 parts per thousand and +25.4 +/- 5.9 parts per thousand). While sources show distinct delta N-15 NO3- in this multiple source catchment, the overall mixture of NO3- sources generally >95% DIN leads to low variations of delta N-15 NO3- at the mouth of the estuary (+7.7 to +/- 8.4 parts per thousand). Even if estuarine delta N-15 NO3- values are not significantly different from pristine continental and oceanic site (+7.3 parts per thousand and +/- 7.4 parts per thousand), macroalgae delta N-15 values are generally higher at the mouth of the estuary. This highlights high anthropogenic DIN inputs in the estuary, and enhanced contribution of N-15-depleted NH4+ in oceanic waters. Although seasonal variations in delta N-15 NO3- are low, the same temporal trends in macroalgae delta N-15 values at estuarine and oceanic sites, and inter-species differences in delta N-15 values, suggest that macroalgae delta N-15 values might be modified by the metabolic response of macroalgae to environmental parameters (e.g., temperature, light, DIN concentrations). Differences between annual and perennial macroalgae indicate both a higher integration time of perennial compared to annual macroalgae and the possible role of passive versus active uptake mechanisms. Further studies are required to characterize the sensitivity of macroalgae fractionation to variable environmental conditions and uptake mechanisms.

Published
2013

34. Food sources used by sediment meiofauna in an intertidal Zostera noltii seagrass bed: a seasonal stable isotope study

Author

Amel Brahmia, Cyril André, Gaël Guillou, Benoit Lebreton, Gilles Radenac, Robert Galois, Marig Grouazel, Pierre Richard, Géraldine Colli, Gérard F. Blanchard, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Ecology, Stable isotope ratio, 010604 marine biology & hydrobiology, Meiobenthos, Intertidal zone, Sediment, δ15N, Aquatic Science, Biology, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Oceanography, Seagrass, 13. Climate action, Benthic zone, [SDE]Environmental Sciences, 14. Life underwater, Zostera, Ecology, Evolution, Behavior and Systematics
Abstract

International audience; In an intertidal Zostera noltii Hornem. seagrass bed, food sources used by sediment meiofauna were determined seasonally by comparing stable isotope signatures (δ13C, δ15N) of sources with those of nematodes and copepods. Proportions of different carbon sources used by consumers were estimated using the SIAR mixing model on δ13C values. Contrary to δ15N values, food source mean δ13C values encompassed a large range, from -22.1‰ (suspended particulate organic matter) to -10.0‰ (Z. noltii roots). δ13C values of copepods (from -22.3 to -12.3‰) showed that they use many food sources (benthic and phytoplanktonic microalgae, Z. noltii matter). Nematode δ13C values ranged from -14.6 to -11.4‰, indicating a strong role of microphytobenthos and/or Z. noltii matter as carbon sources. The difference of food source uses between copepods and nematodes is discussed in the light of source accessibility and availability.

Published
2012

35. Trophic importance of diatoms in an intertidal Zostera noltii seagrass bed: Evidence from stable isotope and fatty acid analyses

Author

Robert Galois, Benoit Lebreton, Gaël Guillou, Gérard F. Blanchard, Françoise Mornet, Camille Pfléger, Gilles Radenac, Pierre Richard, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ressources Halieutiques (LRH), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)

Subjects
0106 biological sciences, microphytobenthos, Intertidal zone, Aquatic Science, Oceanography, 010603 evolutionary biology, 01 natural sciences, Algae, Botany, Organic matter, 14. Life underwater, Zostera, intertidal seagrass bed, chemistry.chemical_classification, biology, food web, 010604 marine biology & hydrobiology, biology.organism_classification, Zostera noltii, fatty acid profiles, Food web, stable isotope ratio, Diatom, Seagrass, chemistry, Benthic zone, [SDE]Environmental Sciences, European Atlantic coast
Abstract

A current predominant paradigm emphasizes the role of epiphytic algae for invertebrates in most seagrass food webs. However, in some intertidal Zostera noltii beds, epiphyte biomass is very low compared to microphytobenthos and seagrass biomasses. We assessed the role of microphytobenthos in a temperate intertidal Z. noltii bed by combining stable isotope and fatty acid (FA) analyses on primary producers, composite sources suspended particulate organic matter (SPOM) and sediment surface organic matter (SSOM) and the main macrofaunal consumers. Z. noltii showed high delta C-13 (-9.9 parts per thousand) and high 18:2(n-6) and 18:3(n-3) contents. Microphytobenthos was slightly more C-13-depleted (-15.4 parts per thousand) and had high levels of diatom markers: 14:0, 16:1(n-7)c, 20:5(n-3). Low mean delta C-13 (-22.0 parts per thousand) and large amounts of diatom and bacteria (18:1(n-7)c) markers indicated that SPOM was mainly composed of a mixture of fresh and decayed pelagic diatoms. Higher mean delta C-13 (-17.9 parts per thousand) and high amounts of diatom FAs were found in SSOM, showing that microphytobenthic diatoms dominate. Very low percentages of 18:2(n-6) and 18:3(n-3) in consumers indicated a low contribution of Z noltii material to their diets. Grazers, deposit and suspension-deposit feeders had delta C-13 close to microphytobenthos and high levels of diatom FAs, confirming that microphytobenthos represented the main part of their diet. Lower delta C-13 and higher amounts of flagellate FM - 22:6(n-3) and 16:4(n-3) - in suspension feeders indicated that their diet resulted from a mixture of SPOM and microphytobenthos. These results demonstrate that invertebrates do not consume high amounts of seagrass and highlight the main role of benthic diatoms in this intertidal seagrass bed. (C) 2010 Elsevier Ltd. All rights reserved.

Published
2011

36. Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron oyster farming bay: Insights from stable isotopes and microalgae ecology

Author

Pascale Malestroit, Nathalie Malet, Mireille Ryckaert, Pierre-Guy Sauriau, Gaël Guillou, Centre de Recherche sur les Ecosystèmes Littoraux Anthropisés (CRELA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), LER/LR, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Département de la Charente-Maritime, France, CNRS, and IFREMER

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, microphytobenthos, Marennes-Oléron Bay, Oyster farming, Aquatic Science, Oceanography, 01 natural sciences, heatwave, Phytoplankton, 14. Life underwater, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Detritus, biology, Ecology, Terrigenous sediment, 010604 marine biology & hydrobiology, Marennes Oléron Bay, Pelagic zone, Estuary, biology.organism_classification, Zostera noltii, suspended particulate organic matter, 13. Climate action, Benthic zone, phytoplankton, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, mudflat
Abstract

The aim of this study was to distinguish between sources of the complex variety of Marennes-Oléron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oléron oyster farming bay. Basic biomarkers (Chl a, C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ13C = −250/00 to −230/00) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ13C = − 220/00 to −190/00); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ13C = −21 to −230/00) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003—the warmest summer on record in southern France and Europe—SPOM was particularly enriched for 13C, with δ13C values ranging from −140/00 to −120/00. Pulses in δ13C values, indicative of 13C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oléron Bay may lead to differences in the quality of the trophic environment available for reared oysters.

Published
2008

37. Spatio-temporal variations in intertidal mudflat erodability: Marennes-Oléron Bay, western France

Author

Francis Orvain, Pierre Le Cann, Gaël Guillou, Pierre-Guy Sauriau, P. Le Hir, M. Paillard, Centre de Recherche sur les Ecosystèmes Marins et Aquacoles (CREMA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Physiologie et Ecophysiologie des Mollusques Marins (PE2M), 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), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), CNRS, IFREMER, and Région Poitou-Charente, France

Subjects
0106 biological sciences, Chlorophyll a, 010504 meteorology & atmospheric sciences, Intertidal zone, Hydrobia ulvae, Scrobicularia plana, Aquatic Science, Oceanography, 01 natural sciences, Resuspension, chemistry.chemical_compound, Intertidal mudflat, 14. Life underwater, Erodability, 0105 earth and related environmental sciences, biology, [CHIM.ORGA]Chemical Sciences/Organic chemistry, 010604 marine biology & hydrobiology, Microphytobenthos, Sediment, Geology, 15. Life on land, biology.organism_classification, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, Hydrobia, chemistry, Eris, Erosion, Bioturbation, EPS, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract

A portable erosion device (ERIS) was deployed in November 2000 and May 2001 to investigate the spatio-temporal variation of fine-grained sediment erosion over a transect on the intertidal mudflats of Marennes-Oleron Bay, western France. The objective was to relate changes in bed erodability over diurnal emersion periods to bioturbation, rapid changes in sediment characteristics, and microphytobenthos biomass. Macrofaunal assemblages were dominated by the bivalve, Scrobicularia plana, on the upper mudflat, and by the gastropod, Hydrobia ulvae. on the middle mudflat. A power relationship was obtained where tau(cr) was plotted as a function of sediment density. Results from the upper part of the mudflat deviated from this relationship due to bioturbation by S. plana. No influence of microphytobenthos (either chlorophyll a or extracellular polymeric substances (EPS) content) was found on tau(cr).The bivalve feeding activities altered consolidated sediments (sediment dry mass concentration of similar to 700 g1(-1)) so that they became resuspended easily (tau(cr) < 1 Pa). Fluff layer erosion was observed, with an erosion rate dependent upon the biomass of H. ulvae. It was also found that bioturbation by H. ulvae was implicated (combined with grazing activities) in chl a resuspension during the erosion of the fluff layer. Snail bioturbation stimulated the chl a enrichment of eroded material. whilst the high snail biomass produced a decrease in suspended chl a due to higher grazing rates. (c) 2007 Published by Elsevier Ltd.

Published
2007

38. Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability.

Author

Camille de la Vega, Benoit Lebreton, Ursula Siebert, Gael Guillou, Krishna Das, Ragnhild Asmus, and Harald Asmus

Subjects
Medicine, Science
Abstract

The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight.

Published
2016
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