Collaborative: Snow Petrel Mumiyo: A Record of Food-Web Variability During the Holocene

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The Snow Petrel, Pagadroma nivea, is an abundant seabird species that occurs only in pack-ice covered seas of the Southern Ocean and nests among talus slopes of ice-free nanataks. It has been shown that at some ice-free locations this species has nested for 35,000 years. The proposed project will focus on the isotopic analysis of laminated deposits of Snow Petrel 'mumiyo' (i.e., stomach oil that accumulates around nesting cavities) dating back 10,000 years before present. The samples are in hand and were collected at the Bunger Hills, East Antarctica. These analyses will assess the variation in the structure of certain portions of the upper food web of the Southern Ocean in response to climate variation. Profiles of 18O and 2H will be analyzed to reveal correspondence to long-term fluctuations in marine climate, while 13C and 15N will be used to assess food web fluctuations. The Snow Petrel feeds on either krill, at one trophic level, or fish, at the next highest. Thus results may reveal long-term switches in diet as a function of availability in these two classes of prey. Availability of these prey to Snow Petrels is in turn known to be affected by the variation in sea ice cover. Sea ice cover varies with climate, as revealed in sediment cores of coastal Antarctica. The proposed analyses have the potential to reveal corresponding changes in higher in the food web.