Analysis of stable isotope ratios in blood of tracked wandering albatrosses fails to distinguish a δ13C gradient within their winter foraging areas in the southwest Atlantic Ocean

• Published in: Rapid Communications in Mass Spectrometry
• Main Authors: Ceia, Filipe R., Ramos, Jaime A., Phillips, Richard A., Cherel, Yves, Jones, Daniel C., Vieira, Rui P., Xavier, José C.
• Other Authors: Marine and environmental research centre - IMAR-CMA (Coimbra, Portugal), University of Coimbra Portugal (UC), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDE]Environmental Sciences; Austral; Bird Island; Wandering Albatross
• Online Access: https://hal.science/hal-01289138; https://doi.org/10.1002/rcm.7401

International audience RATIONALE: The main limitation of isotopic tracking for inferring distribution is the lack of detailed reference maps ofthe isotopic landscape (i.e. isoscapes) in the marine environment. Here, we attempt to map the marine δ13C isoscape forthe southwestern sector of the Atlantic Ocean, and assess any temporal variation using the wandering albatross as amodel species.METHODS: Tracking data and blood and diet samples were collected monthly from wandering albatrosses rearingchicks at Bird Island, South Georgia, during the austral winter between May and October 2009. The δ13C and δ15N valueswere measured by mass spectrometry in plasma and blood cells, and related to highly accurate data on individualmovements and feeding activity obtained using three types of device: GPS, activity (immersion) loggers and stomachtemperature probes.RESULTS: The tracked birds foraged in waters to the north or northwest of South Georgia, including the Patagonianshelf-break, as far as 2000 km from the colony. The foraging region encompassed the two main fronts in the SouthernOcean (Polar and Subantarctic fronts). The δ13C values varied by only 2.1 ‰ in plasma and 2.5 ‰ in blood cells, andno relationships were found between the δ13C values in plasma and the mean latitude or longitude of landings or feedingevents of each individual.CONCLUSIONS: The failure to distinguish a major biogeographic gradient in δ13C values suggest that these values in thesouth Atlantic Ocean are fairly homogeneous. There was no substantial variation among months in either the δ13C or theδ15N values of plasma or blood cells of tracked birds. As birds did not show a significant change in diet composition orforaging areas during the study period, these results provide no evidence for major temporal variation in stable isotoperatios in consumer tissues, or in the regional marine isoscape in the austral winter of 2009.