Microbiological and biogeochemical investigations of the microbial driven methane dynamic in the Siberian Arctic during glacial-interglacial climate changes

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The currently observed climate change due to global warming is expected to have a strong impact especially on the Arctic permafrost environments. The thawing of permafrost is suggested to be associated with a massive release of greenhouse gases, in particular methane. Thus, Arctic permafrost regions play a fundamental role within the global carbon cycle and the future development of the Earth’s climate. For the understanding how the system will respond to climate changes it is not only important to investigate the current status of carbon turnover but also how the system reacted to climate changes in the past. Therefore, in the proposed project the microbial driven methane dynamic in Arctic wetlands of Northeast Siberia during glacial-interglacial climate changes will be investigated. For this purpose a combined stratigraphic analyses of microbial lipid markers and ribosomal RNA will be applied on permafrost and lake sediments of Late Pleistocene to Holocene age. The permafrost and lake sediments were recovered from the El’gygytgyn Lake region in the scope of the ICDP project “Scientific Drilling at El’gygytgyn Crater Lake” from November 2008 to May 2009. The El’gygytgyn Lake represents an ideal case study because the region was unglaciated since the time of the meteorite impact. Thus, the sediments in this region archive 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 deepen our knowledge on the variations within the microbial communities during climate changes and the effect of these changes on the microbial driven methane cycling.