Decadal to centennial variability of (sub-) Arctic sea ice distribution and its paleoenvironmental significance

The modern sea ice loss has raised the concern about the natural variability of Arctic sea ice and its relation to short term climate changes. The reconstruction of past sea ice changes based on sediment cores and analyses of specific proxies provides vital knowledge about the natural variability of sea ice in pre-industrial times. Particular important areas for sea ice reconstructions are the shelves around Greenland. They underlie the major outflow of freshwater and sea ice from the Arctic to the North Atlantic. In this context, the late Holocene is of major interest, as it encompasses several well-known short-term climate events. For past sea ice conditions and open-water phytoplankton production, the application of specific biomarkers (IP25, HBI III, brassicasterol and dinosterol) have proven as useful and reliable proxies. In this study, biomarker concentrations in surface sediments are compared to modern sea ice concentrations to confirm the applicability of the IP25/PIP25 approach. Following this, late Holocene sea ice conditions are reconstructed on two sediment cores from the East (PS2641-4/PS2641-5) and West Greenland Shelf (MSM05/3-343310).