Reconstruction of the Methane Cycle in Late Pleistocene Permafrost of the El’gygytgyn Lake Region, Siberia

Funding

DFG (2008-2010); AWI, Helmholtz Zentrum Potsdam

PhD candidate

Juliane Griess

Cooperation

Kai Mangelsdorf
Biogeochemistry
Helmholtz Centre Potsdam
Potsdam, Germany

Martin Melles
PI ICDP Project
University of Cologne
Cologne, Germany

Background

Permafrost of more than 500 m depth characterises the landscape of the El’gygytgyn Lake, which has been recently accepted as a deep drilling target in the scope of the International Continental Scientific Drilling Program (ICDP). The lake represents a 12 km in diameter and 175 m deep Arctic crater lake located in Chukhotka, Northeast Siberia. The impact crater is placed in Cretaceous continental volcanics belonging to the Okhotsk-Chukotka volcanic belt. The climate in the region is cold and dry with mean January temperatures of about ‑35°C and mean July temperatures of about +6°C. The region is assumed to be unglaciated since the time of the meteorite impact approximately 3.6 Ma ago. Beside the aspired two deep lake sediment drillings a land drilling of up to 200 m depth into the permafrost deposits has been undertaken in autumn 2008. This permafrost core represents the longest continuous and undisturbed permafrost record in the Arctic. Paleoclimate data reconstructed from lake sediment cores recovered during three former expeditions showed that the El’gygytgyn Lake region went through four major climate-induced stages during the last 300,000 years, which were described as “cold + moist”, “cold + dry”, “warm” and “peak warm”. This makes the El’gygytgyn Lake region to an ideal model system for studying the response of the methane cycle to climate change during the Holocene and Late Pleistocene and the response of key organisms involved in this process.