Marine ecosystem response to late Pleistocene climate conditions- evidence from snow petrel stomach oil deposits ("mumiyo") in East Antarctica

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During the Last Glacial Maximum (LGM) expanded ice shelves and sea ice around the Antarctic continent affected global thermohaline circulation as well as endemic Antarctic biota. Under these glacial conditions coastal polynyas have been identified as important sites of Antarctic Bottom Water formation and as glacial refuges for marine biota. Knowledge about the existence of such polynyas off Dronning Maud Land (East Antarctica) comes from the in-land breeding sites of snow petrels. Records of past snow petrel colonies are stomach oil deposits (mumiyo), which form in front of the nests. Radiocarbon dating showed that the birds occupied the presently ice-free mountain ranges at least during the past 60 ka, which does not only imply un-glaciated terrestrial areas, but also points to the existence of marine feeding grounds with reduced sea ice, hence polynyas. In the proposed project we want use mumiyo deposits from different regions in East Antarctica for detailed reconstructions of marine and terrestrial environmental conditions. We suggest geochemical, paleontological and isotopic proxies to detect changes in the available food resources for snow petrels, in sea ice in coastal regions and in conditions at the terrestrial breeding habitat of snow petrels under glacial and Holocene conditions. This will lead to a better understanding of biogeochemical cycles, food web structure and the response of marine ecosystems to glacial climate conditions.