The Saint Lawrence Island Polynya: A 25-Year Evaluation of an Analogue for Climate Change in Polar Regions

Abstract

The northern Bering Sea in the Pacific Arctic is seasonally ice covered, and includes winter polynyas (open areas in ice-covered seas). Overall, this marine system climatically in the winter is little different from the ice-covered Arctic Ocean proper. The macrofauna living in the sediments in this region provide prey for sentinel benthivores in the Arctic, including walrus, gray whales, bearded seals, and diving sea ducks. We have been evaluating the area south of St. Lawrence Island (SLI) for the last 25 years (1990–2015) and this chapter provides a synthesis and overview of ecosystem dynamics in this region seasonally. We initiated our studies during the spring-summer sea ice transition to open water period (May–August) for a decade from 1988 to 1998, but had the opportunity from 1999 to 2007 to use icebreakers for research cruises in the late winter to early spring transition period (March–June), as well as for late winter observations (March–April) from 2008 to 2010. In 2010 we facilitated the development of the Distributed Biological Observatory (DBO), a national and international network of coordinated cruises at five latitudinally arrayed transect lines from south of SLI (DBO1) north to Barrow, Alaska (DBO5). DBO1 includes five time series stations that have been sampled over two decades. The opportunity to sample in different seasons has allowed us to evaluate the phenology of physical, chemical, and biological patterns using an ecosystem approach to understand the transitions. The overall picture that emerges from these seasonal observations is of a biologically active system with strong atmospheric and hydrographic controls that predetermine nutrient distributions and water column mixing through brine rejection. These processes ultimately influence the intensity of seasonal productivity and associated activities of biological components from ice algae to zooplankton to the benthos, and to apex predators that are emblematic features of this subpolar ecosystem that is a sentinel for Arctic-subarctic interactions.

Jacqueline M. Grebmeier and Lee W. Cooper

Jackie Grebmeier and Lee Cooper met at the University of California (UC) Bodega Bay Marine Laboratory in spring 1976 where we studied marine worms and played in the mud. Lee graduated from UC Santa Cruz in 1978 and Jackie graduated from UC Davis in 1977, with a Masters from Stanford University in 1978. In the early 1980s we went to the University of Washington for Masters programs in Botany (Lee) and Marine Affairs/Oceanography (Jackie), then northward to Alaska where we undertook research on Arctic ecosystems (Lee on seagrasses and stable isotopes and Jackie on benthic communities and pelagic-benthic coupling). We both received our Ph.D. degrees in Oceanography from the University of Alaska Fairbanks (Lee in 1986, the year we got married, and Jackie in 1987). We then did postdoctoral work in California, Lee at the University of California, Los Angeles in stable isotope geochemistry and Jackie at the University of Southern California on Arctic benthic systems and sediment radioisotopes. We moved to Tennessee in 1988 where we worked at both Oak Ridge National Laboratory and the University of Tennessee in Knoxville. In 2008 we took up Research Professor positions at the Chesapeake Biological Laboratory at the University of Maryland Center for Environmental Sciences where we are currently located. Besides science, we have managed to raise one daughter, Ruth Cooper, who is a senior at the University of Notre Dame, and one very friendly and tolerant cat named Emily.