Evolution of the Methane Cycle in the Siberian Arctic: Insights from Microbiological and Biogeochemical Studies

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In the scope of the proposed project the evolution of the methane cycle in permafrost environments of Northeast Siberia will be investigated. Of particular interest is the understanding of microbial processes and the identification of the main microbial players involved in the carbon decomposition under changing climatic conditions in the present and past. For this purpose a combined highresolution stratigraphic analyses of microbial lipid markers and ribosomal RNA (quantitative and qualitative microbial biomarkers) will be applied on permafrost deposits with an age of up to 300,000 years. The permafrost core will be recovered from the El'gygytgyn Lake region in the scope of the ICDP project "Scientific Drilling at El'gygytgyn Crater Lake" in spring 2008. The El'gygytgyn Lake represents an ideal case study because the region was unglaciated since the time of the meteorite impact. Thus, permafrost in this region went through several climatic stages during its development and it is expected that climatically induced chemical and physical changes in the sedimentary sequences results in variations of the microbial communities concomitantly affecting the methane gas fluxes in the past. The acquired data will fill fundamental gaps in our knowledge on the paleo carbon dynamics, the development of microbial communities under changing environmental conditions, and will be further used for the understanding and prediction of the future development of the methane cycle in permafrost environments.