%0 Journal Article %J Science of The Total Environment %D 2022 %T Climate change influences chlorophylls and bacteriochlorophylls metabolism in hypersaline microbial mat %A Mazière, C. %A Bodo, M. %A Perdrau, M.A. %A Cravo-Laureau, C. %A Duran, Robert %A Christine Dupuy %A Cédric Hubas %B Science of The Total Environment %V 802 %P 149787 %8 Jan-01-2022 %G eng %U https://linkinghub.elsevier.com/retrieve/pii/S0048969721048622 %! Science of The Total Environment %R 10.1016/j.scitotenv.2021.149787 %0 Journal Article %J Progress in Oceanography %D 2020 %T Microbial functional structure and stable isotopic variation of leptocephali across three current zones in the western South Pacific %A Leopold Ghinter %A Christine Dupuy %A Michael J. Miller %A Alexandre Carpentier %A Christel Lefrançois %A Anthony Acou %A Jun Aoyama %A Mari Kuroki %A Liénart, Camilla %A Shun Watanabe %A Katsumi Tsukamoto %A Tsuguo Otake %A Eric Feunteun %K Isotopic signature %K Leptocephali %K Meso-macro-zooplankton %K Microbial loop %K Micronekton %K POM %K Western South Pacific %X The ecology of leptocephali remains poorly known but they appear to feed on marine snow that can vary spatially and temporally according to the food web dynamics. This study provided new information about the position of leptocephali within the functional structure of microbial plankton and other food web components of the western South Pacific (WSP) region at a large geographic scale including the New Caledonia, Fiji, and Samoa islands. The hydrographic structure varied with latitude, and nutrient levels were generally low but somewhat variable. Stable isotopic signatures were examined in relation to the 3 current zones of the eastward flowing South Equatorial Countercurrent (SECC; north), the westward South Equatorial Current (SEC; mid-latitudes), and the eastward South Tropical Countercurrent (STCC; south), and all zones were found to be primarily based on a heterotrophic planktonic functioning that were co-limited by inorganic nitrogen and phosphorus, with biomasses of planktonic groups varying with depth. Isotopic signatures of leptocephali were compared to the signatures of other mesozoplankton, micronekton, and Trichodesmium components of the food web, and in relation to the signatures of particulate organic matter (POM) that varied among the 3 collection depths. The isotopic signatures of six taxa of leptocephali, other taxonomic groups and POM showed interesting variability according to latitude and among some stations. The presence of Trichodesmium at the surface in the STCC zone influenced the isotopic signatures of POM and thus the signatures of leptocephali. The signatures of leptocephali were therefore linked with the overall food web and were consistent with the larvae feeding on marine snow components of POM. The two apparent groups of leptocephali with different isotopic signatures that have also been observed in other oceanic areas may be explained by feeding behavior at different depths or on different types of marine snow. %B Progress in Oceanography %V 182 %P 102264 %G eng %U http://www.sciencedirect.com/science/article/pii/S0079661120300021 %R 10.1016/j.pocean.2020.102264 %0 Journal Article %J Marine Environmental Research %D 2019 %T Modelling the functioning of a coupled microphytobenthic-EPS-bacterial system in intertidal mudflats %A Rakotomalala, C %A Katell Guizien %A Karine Grangeré %A Sébastien Lefebvre %A Christine Dupuy %A Francis Orvain %K Bacillariophyta %K bacteria %K Bacteria (microorganisms) %K bacterial growth %K bacterium %K Biogeochemical modeling %K biogeochemistry %K Biomass %K Carbon %K Carbon and nitrogen %K Carbon and nitrogen ratios %K Diatom %K diel vertical migration %K exopolymer %K Experimental conditions %K Extracellular polymeric substances %K intertidal environment %K intertidal zone %K light %K mesocosm %K microbial community %K Microphytobenthos %K Migration %K modeling %K mudflat %K Nitrogen %K nonhuman %K Nutrient availability %K Nutrients %K nutritional requirement %K organic carbon %K organismal interaction %K Photosynthesis %K Phytobenthos %K Phytoplankton %K polymer %K Review %K simulation %K tide %K vertical migration %X A mechanistic and biogeochemical model was developed to analyze the interactions between microphytobenthos (MPB), bacteria and nutrients in a tidal system. Behavioral vertical migration was hypothesized as being controlled by exogenous factors (tide and light) but also by endogenous factors (carbon and nitrogen requirements). The secretion of Extracellular Polymeric Substances (EPS) during photosynthesis (overflow metabolism) and migration of diatoms was also formulated. Similarities in MPB dynamics between observations and simulations support the assumption that carbon and nitrogen ratios are additional key processes behind the vertical migration of diatoms in the sediment. The model satisfactorily reproduced the three growth phases of the MPB development observed in a mesocosm (the lag phase, the logarithmic growth, and the plateau). Besides, nutrient availability, which could be induced by faunal bioturbation, significantly determined the extent of MPB biomass and development. The plateau phase observed in the last days of simulations appeared to be attributed to a nutrient depletion in the system, emphasizing the importance of nutrient availability. The model, although improvable especially on the formulation of the EPS excretion and bacteria development, already updated understanding of several aspects of benthic-system functioning during experimental conditions. © 2019 Elsevier Ltd %B Marine Environmental Research %V 150 %G eng %U https://www.sciencedirect.com/science/article/abs/pii/S0141113619300704 %R 10.1016/j.marenvres.2019.104754 %0 Journal Article %J Microbial Ecology %D 2018 %T Diel Rhythm Does Not Shape the Vertical Distribution of Bacterial and Archaeal 16S rRNA Transcript Diversity in Intertidal Sediments: a Mesocosm Study %A Lavergne, C. %A Hugoni, M. %A Cédric Hubas %A Debroas, D. %A Christine Dupuy %A Agogué, H. %X

In intertidal sediments, circadian oscillations (i.e., tidal and diel rhythms) and/or depth may affect prokaryotic activity. However, it is difficult to distinguish the effect of each single force on active community changes in these natural and complex intertidal ecosystems. Therefore, we developed a tidal mesocosm to control the tidal rhythm and test whether diel fluctuation or sediment depth influence active prokaryotes in the top 10 cm of sediment. Day- and nighttime emersions were compared as they are expected to display contrasting conditions through microphytobenthic activity in five different sediment layers. A multiple factor analysis revealed that bacterial and archaeal 16S ribosomal RNA (rRNA) transcript diversity assessed by pyrosequencing was similar between day and night emersions. Potentially active benthic Bacteria were highly diverse and influenced by chlorophyll a and phosphate concentrations. While in oxic and suboxic sediments, Thaumarchaeota Marine Group I (MGI) was the most active archaeal phylum, suggesting the importance of the nitrogen cycle in muddy sediments, in anoxic sediments, the mysterious archaeal C3 group dominated the community. This work highlighted that active prokaryotes organize themselves vertically within sediments independently of diel fluctuations suggesting adaptation to physicochemical-specific conditions associated with sediment depth.

%B Microbial Ecology %V 75 %P 364-374. %8 Aug %G eng %U https://doi.org/10.1007/s00248-017-1048-1 %N 2 %R 10.1007/s00248-017-1048-1 %0 Journal Article %J Journal of Experimental Marine Biology and Ecology %D 2018 %T Stable isotopes as tracers can reveal resource allocation in juvenile golden gray mullets (Liza aurata, Risso, 1810) %A Como, S. %A Alexandre Carpentier %A Rossi, F. %A Christine Dupuy %A Richard, P. %A Eric Feunteun %A Lefrançois, C. %X Studies on the nutritional physiology of predator fish in the marine environment have contributed to our understanding of how they adapt to the environment and how they have evolved. Despite the fact that herbivorous and omnivorous fish species are numerous and play a significant role in the ecosystem, there is little information on how they process nutrients and how these are allocated to different tissues. This information could be particularly important for the juvenile stages, when small-sized fish are under high predation pressure and have a limited capability to intake and digest large quantities of food. The mullet Liza aurata ingests surface sediment and obtains its nutritional requirements from the organisms associated with the sediment, including microalgae and bacteria or small invertebrates. This paper examines how the carbon and nitrogen derived from benthic micro-organisms are allocated to the liver and muscle tissues of newborn (young-of-the-year, YOY) and one-year-old (OYO) individuals. After the animals were left feeding on 13C-enriched microalgae and 15N-enriched bacteria for 1 h, we traced the 13C and 15N in the liver and muscle tissues as well as in the blood and the gut. The YOY allocated 99% of the 13C and 88% of the 15N to the muscles, while the liver had a negligible amount of tracers (0.4% and 11% for 13C and 15N). Conversely, in the OYO experiment, the tracers were uniformly distributed throughout the muscle and liver (57% of 13C and 45% of 15N were found in the muscle, whereas 43% of 13C and 55% of 15N were in the liver). Negligible amounts were traced in the blood (<0.1%), while a part of the tracers was not assimilated and remained in the gut of both YOY and OYO fish. These results indicated a size-related shift in resource allocation during first year of growth of L. aurata, probably related to changes in the survival strategies among juveniles. Our results also indicated that stable isotope enrichment can be a helpful tool for studying resource allocation in fish. %B Journal of Experimental Marine Biology and Ecology %V 503 %P 72 - 79 %8 Jan-06-2018 %G eng %U https://www.sciencedirect.com/science/article/pii/S0022098117301971 %! Journal of Experimental Marine Biology and Ecology %R 10.1016/j.jembe.2018.01.009 %0 Journal Article %J Marine Ecology and Progress Series %D 2016 %T Geographic variation in stable isotopic and fatty acid composition of anguilliform leptocephali and particulate organic matter in the South Pacific %A Liénart, Camilla %A Eric Feunteun %A Miller, M J %A Aoyama, J %A Jean-Michel Mortillaro %A Cédric Hubas %A Kuroki, M %A Watanabe, S %A Christine Dupuy %A Alexandre Carpentier %A Otake, T %A Tsukamoto, K %A Tarik Meziane %K Leptocephali · Fatty acids · Stable isotopes · Biomarkers · Trophic ecology · Oceanic currents %X

The feeding ecology of leptocephali has remained poorly understood because they apparently feed on particulate organic matter (POM), which varies in composition, and it is unclear which components of the POM they assimilate. The δ13C and δ15N stable isotope (SI) and fatty acid (FA) compositions of 3 families of leptocephali and POM were compared in 3 latitudinal current zones of the western South Pacific. The δ15N signatures of leptocephali and POM overlapped, with both having their lowest values in the southern current zone. POM in general (across all zones) contained 38 FAs and was rich in saturated FAs (SFA) (16:0, 18:0, 14:0), while leptocephali contained 50 FAs, with high proportions of 16:0, and higher contributions of 22:6ω3, 20:5ω3, 18:1ω9, 16:1ω7 and other FAs than found in the POM. Serrivomeridae leptocephali in the north had higher δ15N signatures and were also distinguished from Nemichthyidae and Muraenidae larvae by their FA compositions (higher SFAs, lower 22:6ω3 and 20:5ω3). Although SI signatures of the Serrivomeridae larvae did not clearly vary with size, 16:0 and 18:0 FA proportions decreased with increasing larval size, and 22:6ω3 and 16:1ω7 increased in larger larvae. Correspondences between the latitudinal variations in nitrogen SI signatures and FA compositions of POM with those of leptocephali and the presence of FA markers of both autotrophic and heterotrophic organisms were consistent with leptocephali feeding on POM. POM can contain various materials from primary producers and heterotrophic microorganisms, but differences in the SI signatures and FA compositions in leptocephali remain to be explained through further research.

%B Marine Ecology and Progress Series %V 544 %P 225-241 %@ doi:10.3354/meps11575 %G eng %0 Journal Article %J Progress in Oceanography %D 2015 %T Stable isotopic composition of anguilliform leptocephali and other food web components from west of the Mascarene Plateau %A Eric Feunteun %A Miller, M.J. %A Alexandre Carpentier %A Aoyama, J. %A Christine Dupuy %A Kuroki, M. %A Pagano, M. %A Réveillac, E. %A Sellos, D. %A Watanabe, S. %A Tsukamoto, K. %A Otake, T. %B Progress in Oceanography %V 137 %P 69-83 %G eng %U https://www.sciencedirect.com/science/article/pii/S0079661115001299 %R 10.1016/j.pocean.2015.05.024 %0 Journal Article %J Journal of Sea Research %D 2014 %T Bacterial dynamics in a microphytobenthic biofilm: A tidal mesocosm approach %A Hélène Agogué %A Clarisse Mallet %A Francis Orvain %A Margot de Crignis %A Françoise Mornet %A Christine Dupuy %B Journal of Sea Research %V 92 %P 144-157 %8 09/2014 %G eng %0 Journal Article %J Journal of Sea Research %D 2014 %T Feeding ecology of Liza spp. in a tidal flat: Evidence of the importance of primary production (biofilm) and associated meiofauna %A Alexandre Carpentier %A Como, S. %A Christine Dupuy %A Lefrançois, C. %A Eric Feunteun %B Journal of Sea Research %V 92 %P 86-91 %G eng %U https://www.sciencedirect.com/science/article/pii/S1385110113002013 %R 10.1016/j.seares.2013.10.007 %0 Journal Article %J Journal of Sea Research %D 2014 %T How does the resuspension of the biofilm alter the functioning of the benthos-pelagos coupled food web of a bare mudflat in Marennes-Oléron Bay (NE Atlantic)? %A Saint-Béat, B. %A Christine Dupuy %A Agogué, H. %A Alexandre Carpentier %A Chalumeau, J. %A Como, S. %A David, V. %A De Crignis, M. %A Duchêne, J.-C. %A Fontaine, C. %A Eric Feunteun %A Katell Guizien %A Hartmann, H. %A Lavaud, J. %A Sébastien Lefebvre %A Lefrançois, C. %A Mallet, C. %A Montanié, H. %A Mouget, J.-L. %A Francis Orvain %A Ory, P. %A Pascal, P.-Y. %A Radenac, G. %A Richard, P. %A Vézina, A.F. %A Nathalie Niquil %B Journal of Sea Research %V 92 %P 144-157 %G eng %U https://www.sciencedirect.com/science/article/pii/S138511011400029X %R 10.1016/j.seares.2014.02.003 %0 Journal Article %J Journal of sea research %D 2014 %T How does the resuspension of the biofilm alter the functioning of the benthos–pelagos coupled food web of a bare mudflat in Marennes-Oléron Bay (NE Atlantic)? %A Saint-Béat, B %A Christine Dupuy %A Agogue, Helene %A Alexandre Carpentier %A Chalumeau, J %A Como, Serena %A David, Valérie %A Margot de Crignis %A Duchêne, J C %A Fontaine, C %A others %B Journal of sea research %V 92 %P 144–157 %G eng %0 Journal Article %J Journal of Sea Research %D 2014 %T Relevance of macrozoobenthic grazers to understand the dynamic behaviour of sediment erodibility and microphytobenthos resuspension in sunny summer conditions %A Francis Orvain %A Katell Guizien %A Sébastien Lefebvre %A Martine Bréret %A Christine Dupuy %B Journal of Sea Research %V 92 %P 46-55 %8 09/2014 %G eng %0 Journal Article %J Journal of Sea Research %D 2014 %T Seasonal dynamics of extracellular polymeric substances (EPS) in surface sediments of a diatom-dominated intertidal mudflat (Marennes–Oléron, France) %A Guillaume Pierre %A Jean-Michel Zhao %A Francis Orvain %A Christine Dupuy %A Géraldine Klein %A Marianne Graber %A Thierry Maugard %B Journal of Sea Research %V 92 %P 26-35 %8 09/2014 %G eng %0 Journal Article %J Journal of Sea Research %D 2014 %T Sequential resuspension of biofilm components (viruses, prokaryotes and protists) as measured by erodimetry experiments in the Brouage mudflat (French Atlantic coast) %A Christine Dupuy %A Clarisse Mallet %A Katell Guizien %A Hélène Montanié %A Martine Bréret %A Françoise Mornet %A Camille Fontaine %A Caroline Nérot %A Francis Orvain %B Journal of Sea Research %V 92 %P 56-65 %8 09/2014 %G eng %0 Journal Article %J Journal of Sea Research %D 2014 %T Structures of benthic prokaryotic communities and their hydrolytic enzyme activities resuspended from samples of intertidal mudflats: An experimental approach %A Clarisse Mallet %A Hélène Agogué %A Frédérique Bonnemoy %A Katell Guizien %A Francis Orvain %A Christine Dupuy %B Journal of Sea Research %V 92 %P 158-169 %8 09/2014 %G eng %0 Journal Article %J Journal of Sea Research %D 2014 %T Tidal and seasonal effects on the short-term temporal patterns of bacteria, microphytobenthos and exopolymers in natural intertidal biofilms (Brouage, France) %A Francis Orvain %A Margot de Crignis %A Katell Guizien %A Sébastien Lefebvre %A Clarisse Mallet %A Takahashi, E %A Christine Dupuy %B Journal of Sea Research %V 92 %P 6-18 %8 09/2014 %G eng