High inter-species variability in elemental composition of the twilight zone fauna varies implications for predators and exploitation by humans

• Published in: Environmental Research
• Main Authors: Chouvelon, Tiphaine, Munschy, Catherine, Bruzac, Sandrine, Caurant, Florence, Churlaud, Carine, Crochet, Sylvette, Guillou, Gaël, Mauffret, Aourell, Méndez-Fernandez, Paula, Niol, Jasmin, Sireau, Teddy, Steinberg, Claire, Wessel, Nathalie, Spitz, Jérôme
• Other Authors: Observatoire PELAGIS UMS 3462 (PELAGIS), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Institut national des sciences de l'Univers (INSU - CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Biogéochimie des Contaminants Organiques (LBCO), Biogéochimie et Ecotoxicologie (BE), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Biogéochimie des Contaminants Métalliques (LBCM), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut national des sciences de l'Univers (INSU - CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Service Valorisation de l'Information pour la gestion Intégrée Et la Surveillance (VIGIES), Dynamiques des Écosystèmes Côtiers (DYNECO)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Energy density; Inorganic elements; Trace metals; Matter transfers; Environmental and health thresholds; Mesopelagic; [SDE]Environmental Sciences; North East Atlantic
• Online Access: https://hal.science/hal-03685500; https://doi.org/10.1016/j.envres.2021.112379

International audience While the importance of oceanic micronektonic species in biogeochemical cycles and in the transfer of matter in food webs is globally recognized, specific knowledge on elemental concentrations and their variability within this community is still poorly documented. Here, we report for the first time in the Bay of Biscay, North-East Atlantic, the body composition in various biological parameters and chemical elements of a meso-to bathypelagic micronektonic community. Stable carbon and nitrogen isotope compositions (δ13C, δ15N), C:N ratios, energy density, as well as the concentrations in 6 macro-minerals and 13 trace elements including essential (micro-nutrients) and non-essential elements (undesirables, with no know biological function) were measured in whole organisms of 4 crustacean and 11 fish species caught simultaneously around 800 m depth. The results showed a low variability of δ13C values, confirming that all studied species share the same habitat. On the contrary, large differences were observed among species for several elements. Trace elements showed the greatest variability (i.e. larger range of values), especially silver (Ag), arsenic (As), cadmium (Cd), cobalt and vanadium. Significant differences were also revealed among taxa for Ag, As, Cd, copper and strontium concentrations (with crustaceans > fish), as well as for δ15N values and phosphorus concentrations (with fish > crustaceans). Although concentrations varied greatly among species, they could be grouped according to their energy density and composition in 19 chemical elements, through hierarchical clustering analysis. Six functional groups of species have been thus identified, reflecting contrasted nutritional benefit and/or exposure to undesirables for predators feeding on this deep pelagic community. Finally, the concentrations measured for the potentially toxic trace elements (undesirables) exceeded the existing European thresholds for Cd and to a lesser extent mercury (Hg), which point out potential risks ...