Fluxes, Fins, and Feathers Relationships Among the Bering, Chukchi, and Beaufort Seas in a Time of Climate Change

Ocean currents, water masses, and seasonal sea ice formation determine linkages among and barriers between the biotas of the Bering, Chukchi, and Beaufort Seas. The Bering Sea communicates with the Chukchi and Beaufort Seas via northward advection of water, nutrients, and plankton through Bering Strait. However, continuity of the ocean's physical properties is modulated by regional differences in heat, salt, and sea ice budgets, in particular, along the meridional gradient. Using summer density data from zooplankton, fish (bottom and surface trawl), and seabird surveys, we define three biogeographic provinces: the Eastern Bering Shelf Province (the eastern Bering Sea shelf south of Saint Lawrence Island), the Chirikov-Chukchi Province (the eastern Bering Sea shelf north of Saint Lawrence Island [Chirikov Basin] and Chukchi Sea), and the Beaufort Sea Province. Regional differences in summer distributions of biota largely reflect the underlying oceanography. Climate warming will reduce the duration and possibly the extent of seasonal ice cover in the Eastern Bering Shelf Province, but this warming may not lead to increased abundance of some subarctic species because seasonal ice cover and cold (< 2 degrees C) bottom waters on the Bering shelf form a barrier to the northward migration of subarctic bottom fish species typical of the southeastern Bering Sea. While Arctic species that are dependent upon the summer extent of sea ice face an uncertain future, other Arctic species' resilience to a changing climate will be derived from waters that continue to freeze each winter.