SGER: Geologic Constraints on Life in an Antarctic Sub-ice-shelf Environment

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This Small Grant for Exploratory Research supports geologic and biologic research on a newly discovered ecosystem underlying the Larsen-B ice shelf, which collapsed catastrophically in 2002. Through a combination of geochemical measurements of the seawater, sediments, and pore waters, and subsequent molecular analyses of the biota, this project will characterize the community and constrain the role of glacial processes in initiating and sustaining it. The system is the first of its type discovered in polar waters. Known to contain at least bivalves and bacterial mats, it raises questions about the nature and extent of life in sub-ice-shelf environments, especially the source of carbon. The marine mud from nearby embayments has very low organic carbon contents, and the overlying ice shelf secluded the ecosystem from open ocean phytoproduction for over 10,000 years. One hypothesis is that organic carbon is supplied by petroliferous glacial till underlying the site, but overall the work has important implications for understanding life in extreme environments such as those that existed during the Snowball Earth period or on icy worlds such as Mars and Titan. In addition, there may be implications for constraining the global methane budget.The broader impacts of this work include support of undergraduate student research and improving societys understanding of the response of life to global climate change.