The Western Chukchi Sea: Physical Drivers and biological and Geochemical Responses

Robert Pickart, Woods Hole Oceanographic Institution

Abstract

The Chukchi Sea represents a crucial transition zone between the Pacific Ocean and the high
Arctic Ocean. A variety of water masses pass northward through Bering Strait over the course of
the year, supplying heat, freshwater, and nutrients to the Chukchi shelf. Among other things, this
influences ice-melt patterns, stratification, primary production, and benthic activity on the shelf.
However, since all of the Pacific water ultimately exits the shelf into the deep basin, identifying
and understanding the processes in the Chukchi Sea is important not only locally, but also
because of the far-field impacts on the Pacific sector of the Arctic Ocean. Over the last decade,
the Russian-American Long-Term Census of the Arctic (RUSALCA) program has provided an
unprecedented physical-biological data set in the western Chukchi Sea. There have been three
broad shipboard surveys carried out in summer 2004, 2009, and 2012. This proposal seeks
support to carry out a synthesis study to relate the physical drivers on the shelf, including the
circulation, atmospheric forcing, and sea-ice concentration, to different components of the
biological system, including the benthic community and water column distributions of
chlorophyll and zooplankton. Our overall goal is to elucidate the relative roles of the shelf
circulation, atmospheric forcing, and upstream influence (Bering Strait) in determining the
chemical and biological setting in the western Chukchi Sea. This will help us understand how
this important ecosystem functions – and how it might react to the changing environmental
conditions.