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| Michel, Loic; Danis, Bruno; Dubois, Philippe; Eleaume, Marc; Fournier, Jerome; Gallut, Cyril; Jane, Philip; Lepoint, Gilles. |
| In recent years, sea ice cover along coasts of East Antarctica has tended to increase. To understand ecological implications of these environmental changes, we studied benthic food web structure on the coasts of Adélie Land during an event of unusually high sea ice cover (i.e. two successive austral summers without seasonal breakup). We used integrative trophic markers (stable isotope ratios of carbon, nitrogen and sulfur) to build ecological models and explored feeding habits of macroinvertebrates. In total, 28 taxa spanning most present animal groups and functional guilds were investigated. Our results indicate that the absence of seasonal sea ice breakup deeply influenced benthic food webs. Sympagic algae dominated the diet of many key consumers, and... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00500/61194/64726.pdf |
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| Pizzochero, Ana Carolina; Michel, Loic; Chenery, Simon R.; Mccarthy, Ian D.; Vianna, Marcelo; Malm, Olaf; Lepoint, Gilles; Das, Krishna; Dorneles, Paulo R.. |
| The whitemouth croaker, Micropogonias furnieri, is a long-lived fish of high commercial importance in the Western Atlantic Ocean. Here, we used stable isotope ratios of carbon, sulfur and nitrogen and isotopic niche metrics (SIBER) to study feeding habits and track habitat use by whitemouth croakers in Guanabara Bay, an estuary in Rio de Janeiro state, Brazil. Our results highlighted size-related habitat segregation, with small juvenile (< 30 cm) fishes residing mostly inside estuaries, while large adult (> 60 cm) fishes feed mainly in Continental Shelf (CS) waters. Medium adult fishes (30-60 cm) appear to feed in multiple coastal and CS habitats. Moreover, their feeding ecology showed strong temporal differences, linked with seasonal and, to a... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00408/51985/52644.pdf |
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| Pascal, Pierre-yves; Dubois, Stanislas; Goffette, Anais; Lepoint, Gilles. |
| The activity of the geothermal plant at Bouillante in Guadeloupe (French West Indies) releases thioautotrophic bacteria into the coastal environment. Fish counts reveal that fish abundance increases with higher availability of this bacterial resource. In order to evaluate the trophic role of these bacteria, isotopic compositions (C, N, S) of potential consumers were evaluated on transects at increasing distance from the source of bacteria. The 3 mobile fish species examined (Abudefduf saxatilis, Acanthurus bahianus, and Stegastes partitus) ingested and assimilated chemosynthetic bacteria. Similarly, the isotopic composition of the mobile sea urchin Diadema antillarum was different close to the discharge channel, suggesting a diet mainly composed of sulfur... |
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Palavras-chave: Shallow vent; Food web; Sulfur bacteria; Stable isotope. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00404/51511/52256.pdf |
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| Le Bourg, Baptiste; Lepoint, Gilles; Michel, Loic. |
| Rationale Stable isotope analysis is used to investigate the trophic ecology of organisms and, in order to use samples from archived collections, and it is important to know whether preservation methods alter the results. This study investigates the long‐term effects of four preservation methods on sea stars isotopic composition and isotopic niche parameters. Methods We assessed effects of preservation method (freezing, drying, formaldehyde, ethanol) and duration (0, 1, 3, 6, 9, 12 and 24 months) on the stable isotope ratios of carbon, nitrogen and sulfur of sea star tissues. Isotopic ratios were measured using CF‐EA‐IRMS. We also monitored the evolution of commonly used ecological metrics (isotopic niche parameters) throughout the experiment. Results... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00514/62533/66862.pdf |
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| Pizzochero, Ana Carolina; De La Torre, Adrián; Sanz, Paloma; Navarro, Irene; Michel, Loic; Lepoint, Gilles; Das, Krishna; Schnitzler, Joseph G.; Chenery, Simon R.; Mccarthy, Ian D.; Malm, Olaf; Dorneles, Paulo R.; Martínez, María Ángeles. |
| The whitemouth croaker (Micropogonias furnieri) is one of the most commercially important species along the Atlantic coast of South America. Moreover, some of its biological traits (long life span, inshore feeding, high trophic position) make this species a suitable sentinel of coastal pollution. Here, we investigated contamination by multiple legacy and emerging organic pollutants, such as brominated and chlorinated flame retardants, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in whitemouth croakers from two estuaries (Guanabara and Sepetiba Bays) located in industrialized and urbanized areas in Rio de Janeiro State, Southeastern Brazil. Furthermore, we assessed how biological and ecological features could explain... |
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Palavras-chave: Micropogonias furnieri; Brazil; PBDEs; Dechloranes; PCDD/Fs; Stable isotopes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00498/60947/64344.pdf |
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| Mascart, Thibaud; De Troch, Marleen; Remy, François; Michel, Loic; Lepoint, Gilles. |
| Benthic copepods dominate meiofaunal communities from marine phytodetritus, both in terms of numerical abundance and species diversity. Nevertheless, ecological factors driving copepod co-existence and population dynamics are still largely unknown. Here, we aimed to explore feeding habits of four copepod species commonly found in Mediterranean seagrass detritus accumulations, representing distinct eco-morphotypes (planktonic, phytal, epibenthic and mesopsammic). Joint use of fatty acid and stable isotope trophic markers showed that co-occurring harpacticoid copepods have diversified diets. Contrary to what was expected, microphytobenthos does not serve as their main food source. Instead, we found evidence from both techniques that major food items include... |
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Palavras-chave: Macrophytodetritus; Posidonia oceanica; Meiofauna; Stable isotopes; Fatty acids; Isotopic niche; Mixing models; Mediterranean Sea. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00440/55187/60472.pdf |
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| Saucède, Thomas; Guillaumot, Charlène; Michel, Loic; Fabri-ruiz, Salomé; Bazin, Alexis; Cabessut, Marie; Garcia-berro, Aurora; Mateos, Amélie; Mathieu, Olivier; De Ridder, Chantal; Dubois, Philippe; Danis, Bruno; David, Bruno; Diaz, Angie; Lepoint, Gilles; Motreuil, Sébastien; Poulin, Elie; Féral, Jean-pierre. |
| In the Kerguelen Islands, the multiple effects of climate change are expected to impact coastal marine habitats. Species distribution models (SDM) can represent a convenient tool to predict the biogeographic response of species to climate change but biotic interactions are not considered in these models. Nevertheless, new species interactions can emerge in communities exposed to environmental changes and the structure of biotic interactions is directly related to the potential resilience of ecosystems. Trophic interaction studies can help predict species vulnerability to environmental changes using carbon (δ13C) and nitrogen (δ15N) stable isotope ratios to generate trophic models. Using new available data inputs, we generated robust SDM and trophic... |
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Palavras-chave: Fisheries interactions; Sperm whale; Patagonian toothfish; Kerguelen; Depredation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00592/70389/68471.pdf |
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