Dietary plasticity in the bivalve Astarte moerchi revealed by a multimarker study in two Arctic fjords

• Published in: Marine Ecology Progress Series
• Main Authors: Cesare, Silvia De, Meziane, Tarik, Chauvaud, Laurent, Richard, Joelle, Sejr, Mikael K., Thébault, Julien, Winkler, Gesche, Olivier, Frédéric
• Other Authors: Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), 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 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)-Centre National de la Recherche Scientifique (CNRS), Aarhus University Aarhus, Department of Bioscience Aarhus, Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), ANR-11-PDOC-0018,ECOTAB,Effet des changements climatiques sur le benthos en Arctique(2011)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: Filter-feeding bivalves; Pelagic-benthic coupling; Climate change; Arctic benthos; ACL; Fatty acids; Trophic markers; Compound-specific carbon stable isotopes; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Arctic; Greenland; Kongsfjord*; Kongsfjorden; Sea ice; Svalbard
• Online Access: https://hal.univ-brest.fr/hal-01510345; https://hal.univ-brest.fr/hal-01510345/document; https://hal.univ-brest.fr/hal-01510345/file/72330.pdf; https://doi.org/10.3354/meps12035

International audience Arctic coastal ecosystems are likely to be strongly affected by predicted environmental changes such as sea-ice decline and increase in freshwater input and turbidity. These changes are expected to impact primary production dynamics and consequently benthic consumers. The trophic relationship between primary producers and benthic primary consumers were compared in 2 Arctic fjords with different seasonal ice-cover: Young Sound (NE Greenland, a high-Arctic fjord) and Kongsfjorden (Svalbard Archipelago, a sub-Arctic fjord). For comparison, we selected the filter-feeding bivalve Astarte moerchi (belonging to the complex A. borealis), which has a broad geographical distribution in the Arctic. The bivalve digestive glands and food sources were characterized with fatty acids (FAs), bulk stable isotopes, and compound-specific stable isotopes of individual FAs. Our results suggest that diatoms of pelagic and/ or benthic origin are the main contributors to the A. moerchi diet in Young Sound and make up a less important fraction of the diet in the Kongsfjorden population. A contribution by sympagic diatoms is clearly excluded in the sub-Arctic fjord and needs to be further assessed in the Arctic fjord. The A. moerchi diet in sub-Arctic Kongsfjorden is more diversified, varies with season, and has contributions from dinoflagellates and macroalgal detritus. These results, together with higher concentrations of total FAs in the Young Sound population, demonstrated and characterized the trophic plasticity of this bivalve species. Based on these results, we discuss potential effects of environmental factors (shifts in trophic resources, increase in turbidity) for A. moerchi populations in changing Arctic ecosystems.