Experimental shift in diet δ13C: a potential tool for ecophysiological studies in marine bivalves

• Main Authors: Paulet, Yves-Marie, Lorrain, Anne, Richard, Joëlle, Pouvreau, Stéphane
• Other Authors: 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), Thons tropicaux et écosystèmes pélagiques : taxies, interactions et stratégies d'exploitation (THETIS), UMR 100 Physiologie et Ecophysiologie des Mollusques Marins, IFREMER, Site Expérimental d'Argenton, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: envir; geo; Crassostrea gigas
• Online Access: https://hal.archives-ouvertes.fr/hal-00452408/file/PauletOrgGeochemrevised211205.pdf; https://hal.archives-ouvertes.fr/hal-00452408

International audience To test the potential of diet switching experiments in ecophysiological studies of marine invertebrate, stable carbon isotope ratios were measured at different seasons in the gonad, adductor muscle, digestive gland and gills of scallops (Pecten maximus) and oysters (Crassostrea gigas) held for 15 days on a constant diet of phytoplankton depleted in13C. The aim of this study was to determine if differences in carbon incorporation could be detected among species, seasons and organs, and if so, whether it was consistent with their known energy-allocation patterns. After offering the new diet, isotope values of the different organs gradually shifted and significant differences among organs, seasons and species were found. A carbon incorporation index (CII) was calculated to compare the metabolic activity of each organ of the two species between day 0 and day 15. For both species, the digestive gland had the highest CII, the adductor muscle the lowest, while gonad and gills had intermediate values. The CII was generally much higher in P. maximus than in C. gigas, suggesting higher metabolic activity in this species. Seasonal differences in the CII were also observed for the two species and were interpreted as differences in metabolic activity in accordance with our energy allocation scenario. Therefore stable isotope diet switching experiments appear to be of great value for assessing metabolic orientation in bivalves.