Biomarker data of sediment core ARA04C/37, Beaufort Sea, Arctic Ocean@en

A biomarker approach is applied on a well-dated core from the Beaufort Sea directly off the Mackenzie River to reconstruct changes in sea ice, sea surface temperature (SST), primary productivity, and terrigenous input. High-resolution records indicate that the southern Beaufort Sea was nearly ice-free in summer during the last deglaciation and early Holocene, and a seasonal sea-ice cover developed during the mid-late Holocene, coinciding with a drop in terrigenous sediment flux and primary production. Superimposed to this climate-driven long-term change in surface-water characteristics, we document two major flood events during the deglacial to Holocene transition. Such major flood events in the Beaufort Sea region may have profound effect on global climate change, especially during times when the massive Laurentide Ice Sheet (LIS) collapsed, and huge amount of freshwater was drained into the Beaufort Sea. This freshening of the Arctic Ocean may have resulted in increased freshwater export into the North Atlantic, causing reduced North Atlantic deep-water formation. The first flood event occurring at ca. 13 kyr BP is related to the Younger Dryas (YD) flood which may have caused severe cooling. The second flood event occurred at ca. 11 kyr BP, whose existence has been hypothesized for a long time but restricted by quality records. Through studies of our sediment core and other records nearby, we hypothesize that the second flood event is more related to shelf flooding induced by strong coastal erosion.