Habitat and trophic ecology of Southern Ocean cephalopods from stable isotope analyses

• Published in: Marine Ecology Progress Series
• Main Authors: Guerreiro, Miguel, Phillips, Richard A., Cherel, Yves, Ceia, Filipe R., Alvito, Pedro, Rosa, Rui, Xavier, José C.
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), British Antarctic Survey (BAS), Natural Environment Research Council (NERC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Kondakovia longimana; Distribution; Foraging ecology; Southern Ocean; Pelagic ecosystem; Diet; [SDE]Environmental Sciences; Antarctic; Kerguelen; Kerguelen Islands; Indian; Antarc*; Diomedea exulans; Wandering Albatross
• Online Access: https://hal.archives-ouvertes.fr/hal-01212859; https://doi.org/10.3354/meps11266

International audience Although cephalopods play a critical role in marine food webs both as predators andprey, there is a limited knowledge of several basic aspects of their ecology, including their habitatand trophic level, in the Southern Ocean. We examined the ecological role of several SouthernOcean cephalopod species by analyzing δ13C and δ15N values in lower cephalopod beaks obtainedfrom diet samples of wandering albatross Diomedea exulans from South Georgia (AtlanticOcean), and from Crozet and Kerguelen Islands (Indian Ocean). Beak δ13C values ranged from−25.7 to −17.9‰, and were used to assign different cephalopod species to the subtropical, sub-Antarctic or Antarctic Zones. Beak δ15N values were more variable among species, ranging from2.4 to 13.3‰, a difference of ~11‰ that represents approx. 3 trophic levels. Differences amongislands in isotope ratios in the same cephalopod species (higher δ15N and lower δ13C values inSouth Georgia) were attributed to regional oceanographic processes. Antarctic cephalopodsoccupy niches similar to those found in some pelagic fish, seabirds and marine mammals. Ascephalopods are key components in Southern Ocean food webs, these results greatly advance ourunderstanding of the structure, energy and carbon flows in this polar ecosystem.