Holocene variation in the Antarctic coastal food web: linking δD and δ13Cin snow petrel diet and marine sediments

• Published in: Marine Ecology Progress Series
• Main Authors: Ainley, David G, Hobson, K.A., Crosta, X., Rau, G. H., Wassenaar, L. I., Augustinus, Paul C.
• Other Authors: Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institute of Marine Sciences, University of California Santa Cruz (UC Santa Cruz), University of California (UC)-University of California (UC), University of Auckland Auckland
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: Holocene climate change; Antarctica; Food webs; Isotopic analysis; Mumiyo; Pagodroma nivea; Sediment cores; Snow petrel; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Bunger Hills; Dumont d’Urville; East Antarctica; Nivea; The Antarctic; Antarc*; Sea ice; Snow Petrel; Snow Petrels
• Online Access: https://hal.science/hal-02105686; https://hal.science/hal-02105686/document; https://hal.science/hal-02105686/file/Ainley_MEPS2006.pdf; https://doi.org/10.3354/meps306031

International audience Here we present first time evidence for concordant variation in the isotopic signature at both the base and the upper levels of the Antarctic coastal food web during the Holocene. Laminae in sub-fossil deposits of snow petrel Pagodroma nivea stomach oil, known as mumiyo, were collected from nest-sites in the Bunger Hills, East Antarctica. Mumiyo layers were sub-sampled, radiocarbon-dated, and analyzed for δ13C and δD. The obtained values were compared to isotopic variability among layers of an ocean sediment core collected, and similarly dated, in nearby Dumont D’Urville Trough. Overlapping records extended from about 10160 to 526 calendar years before present (cal yr BP). Mumiyo δD values remained relatively constant throughout the sampled period, in accordance with data from nearby ice cores. For 13C, both mumiyo and sediment were enriched during the warmer mid-Holocene (ca. 7500 to 5500 cal yr BP). Isotopic concordance between the core and the mumiyo, and a significant correlation between mumiyo δD and δ13C, suggest that past δ13C variation in plankton was transferred through diet to higher trophic levels and ultimately recorded in stomach oil of snow petrels. Divergence in signals during cold periods may indicate a shift in foraging by the petrels from 13C-enriched neritic prey to normally 13C-depleted pelagic prey, except for those pelagic prey encountered at the productive pack-ice edge during cooler periods, a shift forced by presumed greater sea-ice concentration during those times. Other air-breathing predators would likely respond in the same way.