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Auteur Sebastian, M.; Smith, A.F.; Gonzalez, J.M.; Fredricks, H.F.; Van Mooy, B.; Koblizek, M.; Brandsma, J.; Koster, G.; Mestre, M.; Mostajir, B.; Pitta, P.; Postle, A.D.; Sanchez, P.; Gasol, J.M.; Scanlan, D.J.; Chen, Y. doi  openurl
  Titre Lipid remodelling is a widespread strategy in marine heterotrophic bacteria upon phosphorus deficiency Type Article scientifique
  Année 2016 Publication Revue Abrégée Isme J.  
  Volume 10 Numéro 4 Pages 968-978  
  Mots-Clés (up) 2 enzymes; agrobacterium-tumefaciens; bacterioplankton groups; Ecology; Mediterranean Sea; mesocosm experiment; microbial food-web; north-atlantic ocean; nutrient limitation; phosphate starvation  
  Résumé Upon phosphorus (P) deficiency, marine phytoplankton reduce their requirements for P by replacing membrane phospholipids with alternative non-phosphorus lipids. It was very recently demonstrated that a SAR11 isolate also shares this capability when phosphate starved in culture. Yet, the extent to which this process occurs in other marine heterotrophic bacteria and in the natural environment is unknown. Here, we demonstrate that the substitution of membrane phospholipids for a variety of non-phosphorus lipids is a conserved response to P deficiency among phylogenetically diverse marine heterotrophic bacteria, including members of the Alphaproteobacteria and Flavobacteria. By deletion mutagenesis and complementation in the model marine bacterium Phaeobacter sp. MED193 and heterologous expression in recombinant Escherichia coli, we confirm the roles of a phospholipase C (PlcP) and a glycosyltransferase in lipid remodelling. Analyses of the Global Ocean Sampling and Tara Oceans metagenome data sets demonstrate that PlcP is particularly abundant in areas characterized by low phosphate concentrations. Furthermore, we show that lipid remodelling occurs seasonally and responds to changing nutrient conditions in natural microbial communities from the Mediterranean Sea. Together, our results point to the key role of lipid substitution as an adaptive strategy enabling heterotrophic bacteria to thrive in the vast P-depleted areas of the ocean.  
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  ISSN 1751-7362 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1624  
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Auteur Lopez, N.; Navarro, J.; Barria, C.; Albo-Puigserver, M.; Coll, M.; Palomera, I. doi  openurl
  Titre Feeding ecology of two demersal opportunistic predators coexisting in the northwestern Mediterranean Sea Type Article scientifique
  Année 2016 Publication Revue Abrégée Estuar. Coast. Shelf Sci.  
  Volume 175 Numéro Pages 15-23  
  Mots-Clés (up) abundance; anglerfish lophius-budegassa; Black anglerfish; communities; diet; fish; habits; linnaeus; Lophius budegassa; Lophius piscatorius; osteichthyes; piscatorius; Spatial distributions; Stable isotopes; Stomach contents; Trophic ecology; White anglerfish  
  Résumé The study of the feeding ecology of marine organisms is crucial to understanding their ecological roles and advancing our knowledge of marine ecosystem functioning. The aim of this study was to analyse the trophic ecology of two demersal predator species, black anglerfish (Lophius budegassa) and white anglerfish (L. piscatorius), in the northwestern Mediterranean Sea. Both species are important in the study area due to their high abundance and economic value, but information about their feeding behaviour is scarce. Here, we described the diet composition and ecological role of these two species, investigating whether trophic segregation exists between them and amongst fish of different sizes. In addition, by using experimental survey data we described the spatial distribution of both species to help us interpret trophic behaviour patterns. We gathered samples of two different sizes (small individuals of a total length <30 cm and large individuals >= 30 cm) of both species and combined stomach content analyses (SCA) and stable isotope analyses (SIA) of nitrogen and carbon with isotopic mixing models. Our results revealed that both anglerfish species are opportunistic predators, showing a diet composed mainly of fishes and, to a lesser extent, of crustaceans, with a small proportion of cephalopods, gastropods, bivalves and echinoderms. We found trophic segregation between the two species and the two sizes, indicating that they feed on different prey, in line with differences in their spatial distribution within the study area. This partial partition of food resources could also be explained by the differences in rhythms of activity that were reported in previous studies. In addition, although both species occupied a high position within the food web, our results showed that white anglerfish individuals and the large-sized fish of both species held higher trophic positions. This study demonstrates the usefulness of complementary approaches for trophic studies and confirms that both anglerfish species play an important role as predators in the northwestern Mediterranean Sea food web. (C) 2016 Elsevier Ltd. All rights reserved.  
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  ISSN 0272-7714 ISBN Médium  
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Auteur Nguyen-Kim, H.; Bouvier, T.; Bouvier, C.; Hai, D.N.; Lam, N.N.; Rochelle-Newall, E.; Baudoux, A.C.; Desnues, C.; Reynaud, S.; Ferrier-Pages, C.; Bettarel, Y. url  doi
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  Titre High occurrence of viruses in the mucus layer of scleractinian corals Type Article scientifique
  Année 2014 Publication Revue Abrégée Environmental Microbiology Reports  
  Volume 6 Numéro 6 Pages 675-682  
  Mots-Clés (up) abundance; bacteria; communities; diversity; ecology; gradient gel-electrophoresis; level physiological profiles; microbial; reef; release; water  
  Résumé Viruses attract increasing interest from environmental microbiologists seeking to understand their function and role in coral health. However, little is known about their main ecological traits within the coral holobiont. In this study, a quantitative and qualitative characterization of viral and bacterial communities was conducted on the mucus of seven different coral species of the Van Phong Bay (Vietnam). On average, the concentrations of viruses and bacteria were, respectively, 17- and twofold higher in the mucus than in the surrounding water. The examination of bacterial community composition also showed remarkable differences between mucus and water samples. The percentage of active respiring cells was nearly threefold higher in mucus (m=24.8%) than in water (m=8.6%). Interestingly, a positive and highly significant correlation was observed between the proportion of active cells and viral abundance in the mucus, suggesting that the metabolism of the bacterial associates is probably a strong determinant of the distribution of viruses within the coral holobiont. Overall, coral mucus, given its unique physicochemical characteristics and sticking properties, can be regarded as a highly selective biotope for abundant, diversified and specialized symbiotic microbial and viral organisms.  
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  ISSN 1758-2229 ISBN Médium  
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  Notes <p>ISI Document Delivery No.: AU6GU<br/>Times Cited: 1<br/>Cited Reference Count: 51<br/>Nguyen-Kim, Hanh Bouvier, Thierry Bouvier, Corinne Hai Doan-Nhu Lam Nguyen-Ngoc Rochelle-Newall, Emma Baudoux, Anne-Claire Desnues, Christelle Reynaud, Stephanie Ferrier-Pages, Christine Bettarel, Yvan<br/>EC2CO CORINE Project; TOTAL Foundation; French Institute of Research for Development (IRD)<br/>This work was supported by the EC2CO CORINE Project, the TOTAL Foundation and the French Institute of Research for Development (IRD). We thank Telesphore Sime-Ngando, Didier Debroas, Pham The Thu, Chu Van Thuoc, Sonia Monteil and Delphine Bonnet for their participation in the CORINE mission in Vietnam, their assistance in diving, field operations and technical support during the cruise, and Sebastien Villeger for his advice on statistical analysis. We are also very grateful to Michel Galey, Alexandre Portier and all the staff from Whale Island Resort for their hospitality and help during our stay.<br/>Wiley-blackwell<br/>Hoboken</p> Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1170  
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Auteur Authier, M.; Saraux, C.; Péron, C. doi  openurl
  Titre Variable selection and accurate predictions in habitat modelling: a shrinkage approach Type Article scientifique
  Année 2017 Publication Revue Abrégée Ecography  
  Volume 40 Numéro 4 Pages 549-560  
  Mots-Clés (up) account; distributional data; Ecology; indian-ocean; inference; Mediterranean Sea; regression methods; small pelagic fish; spatial autocorrelation; species distribution models  
  Résumé Habitat modelling is increasingly relevant in biodiversity and conservation studies. A typical application is to predict potential zones of specific conservation interest. With many environmental covariates, a large number of models can he investigated but multi-model inference may become impractical. Shrinkage regression overcomes this issue by dealing with the identification and accurate estimation of effect size for prediction. In a Bayesian framework we investigated the use of a shrinkage prior, the Horseshoe, for variable selection in spatial generalized linear models (GLM). As study cases, we considered 5 datasets on small pelagic fish abundance in the Gulf of Lion (Mediterranean Sea, France) and 9 environmental inputs. We compared the predictive performances of a simple kriging model, a full spatial GLM model with independent normal priors for regression coefficients, a full spatial GLM model with a Horseshoe prior for regression coefficients and 2 zero-inflated models (spatial and non-spatial) with a Horseshoe prior. Predictive performances were evaluated by cross validation on a hold-out subset of the data: models with a Horseshoe prior performed best, and the full model with independent normal priors worst. With an increasing number of inputs, extrapolation quickly became pervasive as we tried to predict from novel combinations of covariate values. By shrinking regression coefficients with a Horseshoe prior, only one model needed to be fitted to the data in order to obtain reasonable and accurate predictions, including extrapolations.  
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  ISSN 0906-7590 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2130  
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Auteur Lett, C.; Barrier, N.; Bahlali, M. doi  openurl
  Titre Converging approaches for modeling the dispersal of propagules in air and sea Type Article scientifique
  Année 2020 Publication Revue Abrégée Ecol. Model.  
  Volume 415 Numéro Pages 108858  
  Mots-Clés (up) Aerial dispersal; Aquatic dispersal; Atmospheric dispersal; Biophysical model; Eulerian model; Lagrangian model; larval dispersal; long-distance dispersal; Marine dispersal; Oceanic dispersal; particle trajectories; population connectivity; Propagule dispersal; reef fish; schooling behavior; seed dispersal; spatially explicit; terrestrial ecology; understanding recruitment; Wind dispersal  
  Résumé Terrestrial plants seeds, spores and pollen are often dispersed by wind. Likewise, most eggs and larvae of marine organisms are dispersed by oceanic currents. It was historically believed that the spatial scale at which dispersal occurs was orders of magnitude smaller for plants than for fish. However, recent empirical estimates of seed and larval dispersal suggest that these dispersal scales are more alike than previously thought. The modeling approaches used to simulate aerial and aquatic dispersal are also converging. Similar biophysical models are developed, in which outputs of Eulerian models simulating the main physical forcing mechanism (wind or currents) are used as inputs to Lagrangian models that include biological components (such as seed terminal velocity or larval vertical migration). These biophysical models are then used to simulate trajectories of the biological entities (seeds, larvae) in three dimensions. We reflect on these converging trends by first putting them into an historical perspective, and then by comparing the physical and biological processes represented in marine larva vs. terrestrial seed dispersal models, the data used for the models output corroboration, and the tools available to perform simulations. We conclude that this convergence offers the opportunity to bridge the gap between two scientific communities which are currently largely disconnected. More broadly, we also see our comparison across systems as a useful way to strengthen the links between aquatic and terrestrial ecology by sharing knowledge, methods, tools, and concepts.  
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  ISSN 0304-3800 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2706  
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