Carbon inventory of Siberian Yedoma and thermokarst deposits
During the late Quaternary, a large pool of organic carbon accumulated in the ice-rich syngenetic frozen deposits and soils preserved in the arctic and subarctic permafrost zone. Because of the potential release of organic carbon from thawing permafrost, the organic-matter (OM) inventory in Yedoma deposits and its degradation features are relevant to current concerns about the effects of global warming. We analyzed OM characteristics like organic carbon content, stable carbon isotopes and carbon-nitrogen ratios. Moreover, lipid biomarkers and sediment parameters like grain size and bulk density of Yedoma and thermokarst deposits exposed at the west coast of Buor Khaya Peninsula (Laptev Sea, Siberia) were studied. With the biomarker approach it is possible to distinguish deposits which were accumulated and frozen during the Pleistocene and Holocene. Late Pleistocene biomarker records indicate cold conditions during the growth/summer period for the late Pleistocene and generally low degradation of the stored OM.