Reconstructing past sea ice cover is a fundamental challenge in paleoceanography/paleoclimate research. Conceptual and numerical models of abrupt changes and the role of high vs. low latitudes as the drivers of climate change invoke sea ice as a principle cause of variability, but to date there have been no reliable proxies of past sea ice extent. Understanding the role of sea ice in past changes also critically impacts our understanding of the consequences of future changes in Arctic sea ice cover. This research calibrates and applies a set of new organic biomarkers (IP25 sea ice index, and TEX86 temperature index) to reconstruct changes in sea ice and associated sea surface temperatures from a series of high sedimentation rate cores from the Bering and Chukchi Seas. Specifically, the researchers will 1) produce a high latitude spatial dataset of relative IP25 concentrations and compare the distribution of these compounds with modern sea ice extent, 2) generate a new database of biomarker distributions in surface sediments from high-latitude oceans and compare with known SST variations, and 3) reconstruct past changes in seasonal sea ice and associated sea surface temperatures during the late glacial and Holocene from selected high latitude sites. In addition to the societal relevance of better understanding the role of sea ice extent in climate change, broader impacts include support of a PhD student, summer research projects for undergraduates, and a new faculty member at the University of Texas at Austin.
