%0 Journal Article %J bioRxiv %D 2021 %T Trophic niche of the invasive gregarious species Crepidula fornicata, in relation to ontogenic changes %A Androuin, Thibault %A Stanislas Dubois %A Cédric Hubas %A Lefebvre, Gwendoline %A Le Grand, Fabienne %A Gauthier Schaal %A Carlier, Antoine %X Crepidula fornicata is a common and widespread invasive gregarious species along the European coast. Among its life-history traits, well documented ontogenic changes in behavior (i.e., motile male to sessile female) suggest a potential shift in feeding strategy across its life stages. Considering the ecological significance of this species in colonized areas, understanding how conspecifics share the trophic resource is crucial. Using fatty acids (FA) and stable isotopes (SI) as complementary trophic markers, we conducted a field survey between late winter and spring to investigate the trophic niche of three ontogenic stages of C. fornicata that bear different sexual (male/female) and motility (motile/sessile) traits. Potential trophic sources were characterized by their pigment, FA and SI compositions and showed well discriminated compositions over the studied period. We showed that the biofilm covering C. fornicata shells harbored a higher biomass of primary producers (i.e., chlorophytes and diatoms) than the surrounding sediment. Over the studied period, we observed a covariation between the three ontogenic stages for both FA and SI compositions which suggest that the trophic niche of C. fornicata does not change significantly across its benthic life. During periods of low food availability, slipper limpets displayed an opportunistic suspension-feeding behaviour, relying on both fresh and detrital organic matter, likely coming from superficial sedimentary organic matter. However, during high food availability (i.e., spring phytoplankton bloom), all ontogenic stages largely benefited from this fresh supply of organic matter (pelagic diatoms in this case). The three ontogenic stages showed consistent differences in FA composition, and to a lesser extent in SI composition. These differences persist over time, as they originate from ontogenic physiological changes (differential growth rates, metabolic rate or gametogenesis) rather than diet discrepancies. This study revealed that multiple trophic markers allow high complementary to characterize organic matter as well as food partitioning between conspecific organisms.
Recommended by PCI Ecology : https://ecology.peercommunityin.org/articles/rec?id=140 %B bioRxiv %P 2020.07.30.229021 %G eng %U https://www.biorxiv.org/content/10.1101/2020.07.30.229021v1.abstract %9 ver. 4 peer-reviewed and recommended by Peer Community In Ecology %R 10.1101/2020.07.30.229021 %0 Journal Article %J Progress in Oceanography %D 2017 %T Dynamics of particulate organic matter composition in coastal systems: A spatio-temporal study at multi-systems scale %A Liénart, Camilla %A Savoye, Nicolas %A Bozec, Yann %A Elsa Breton %A Conan, Pascal %A David, Valérie %A Eric Feunteun %A Karine Grangeré %A Kerhervé, P. %A Lebreton, B. %A Sébastien Lefebvre %A Stéphane L'Helguen %A Mousseau, Laure %A Raimbault, P %A Richard, P. %A Riera, P. %A Sauriau, P.-G. %A Gauthier Schaal %A Aubert, F. %A Aubin, S. %A Bichon, S. %A Boinet, C. %A Bourasseau, L. %A Bréret, M. %A Caparros, J. %A Cariou, T. %A Charlier, K. %A Claquin, P. %A Vincent Cornille %A Corre, A.-M. %A Costes, L. %A Crispi, O. %A Muriel Crouvoisier %A Czamanski, M. %A Del Amo, Y. %A Derriennic, H. %A Dindinaud, F. %A Durozier, M. %A Hanquiez, V. %A Antoine Nowaczyk %A Devesa, J. %A Ferreira, S. %A Fornier, M. %A Garcia, F. %A Garcia, N. %A Geslin, S. %A Emilie Grossteffan %A Gueux, A. %A Guillaudeau, J. %A Guillou, G. %A Joly, O. %A Lachaussée, N. %A Lafont, M. %A Lamoureux, J. %A Lecuyer, E. %A Lehodey, J.-P. %A Lemeille, D. %A Leroux, C. %A Macé, E. %A Maria, E. %A Pineau, P. %A Petit, F. %A Pujo-Pay, M. %A Rimelin-Maury, P. %A Sultan, E. %K bacterium %K benthos %K biogeochemistry %K Biological materials %K C and n stable isotopes %K C:N ratio %K Carbon %K carbon isotope %K Coastal systems %K coastal zone %K Fluid dynamics %K France %K geomorphology %K Hydrodynamics %K Isotopes %K isotopic ratio %K Mediterranean sea %K Meta analysis %K meta-analysis %K Mixing %K Mixing models %K nitrogen isotope %K Organic compounds %K particulate organic matter %K Particulate organic matters %K Phytoplankton %K prokaryote %K Rivers %K seasonality %K spatiotemporal analysis %K stable isotope %K Surface water %K Surface waters %K terrestrial deposit %K Time series %X 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 (8–19%) and/or river (7–19%) POM sources, and (3) the Mediterranean systems characterized by the contribution of diazotroph organisms (ca. 14%). A continent-to-ocean gradient of river 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. © 2017 Elsevier Ltd %B Progress in Oceanography %V 156 %P 221-239 %G eng %U https://www.sciencedirect.com/science/article/abs/pii/S0079661116301914 %R 10.1016/j.pocean.2017.03.001 %0 Journal Article %J Continental Shelf Research %D 2015 %T Spatial changes in fatty acids signatures of the great scallop Pecten maximus across the Bay of Biscay continental shelf %A Nerot, C %A Tarik Meziane %A Gauthier Schaal %A Grall, J %A Lorrain, A %A Paullet, Y-M %A Kraffe, E %K Depth gradient %K fatty acids %K Metabolism %K Pecten maximus %K Trophic markers %X

The spatial variability of food resources along continental margins can strongly influence the physiology and ecology of benthic bivalves. We explored the variability of food sources of the great scallop Pecten maximus, by determining their fatty acid (FA) composition along an inshore–offshore gradient in the Bay of Biscay (from 15 to 190 m depth). The FA composition of the digestive gland showed strong differences between shallow and deep-water habitats. This trend was mainly driven by their content in diatom-characteristic fatty acids, which are abundant near the coast. Scallops collected from the middle of the continental shelf were characterized by higher contents of flagellate markers than scallops from shallow habitats. This could be related to a permanent vertical stratification in the water column, which reduced vertical mixing of waters, thereby enhancing organic matter recycling through the microbial loop. In the deeper water station (190 m), FA compositions were close to the compositions found in scallops from shallow areas, which suggest that scallops could have access to the same resources (i.e. diatoms). Muscle FA composition was more indicative of the physiological state of scallops over this depth range, revealing contrasting reproductive strategies among the two coastal sites and metabolic or physiological adaptation at greater depth (e.g. structural and functional adjustments of membrane composition). This study therefore revealed contrasted patterns between shallow and deeper habitats for both P. maximus muscle and digestive gland tissues. This emphasizes the variability in the diet of this species along its distribution range, and stresses the importance of analyzing different tissues for their FA composition in order to better understand their physiology and ecology.

%B Continental Shelf Research %V 109 %P 1-9 %8 15/10/2015 %G eng