Meltwater Discharge History in the Arctic: Beaufort Sea-Mackenzie River During the Deglacial Period


OCCI Project Funded: 2005

Proposed Research

The goal of this project is to construct a history of meltwater discharge into the Arctic Ocean through the Mackenzie River system during the most recent deglaciation. This research will provide insight into an extremely important climate question: How sensitive is the Atlantic overturning circulation to reduced salinity in the Arctic Ocean and polar North Atlantic? Accurate future projections of climate require this knowledge, yet the best examples of past changes in Atlantic overturning are in the geological record. It is clear that Atlantic salinity is now changing in ways that may affect circulation and heat transport to the North Atlantic: high latitude locations have been freshening over the last 40 years, and reduced overturning may already be underway. Yet, it is difficult to know how much of a salinity change is needed to alter the circulation in a significant way.  Physical oceanographers are unsure, and the numerous numerical simulations of future greenhouse-gas-induced climate change predict a full range of outcomes. To fully understand how sensitive the circulation is to changing salinity requires study of the geological record and specific knowledge of the Arctic Ocean’s role in these changes. 

The approach here will be to develop a radiocarbon-dated chronology of salinity changes derived from cores taken in the Beaufort Sea in 1989 by the Polar Star and stored in WHOI’s McLean core lab (Figure 3). The cores are in excellent condition and remain unsampled. This work will produce a relatively high-resolution record (by Arctic Ocean standards) of the deglacial meltwater discharge which will be compared with independent histories of Atlantic overturning during the deglaciation. 

The data sets generated by this research will be archived at the World Data Center for Paleoclimatology at the National Geophysical Data Center and freely available to other researchers.