The northeastern Chukchi Sea: A complex high-latitude ecosystem

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The enormously productive Chukchi Sea shelf arises as a consequence of water transport from the Pacific Ocean to the Arctic Ocean through Bering Strait and thus forms a transition zone between the borealarctic Bering Sea and the high-arctic Arctic Ocean. These contrasts are particularly evident on the northeastern Chukchi Sea shelf in summer and fall and are related to the bathymetry of the shelf, in conjunction with seasonal changes in ice-cover and winds and Bering Strait transport. These factors shape this ecosystem’s spatio-temporal structure and processes. In aggregate, these physical factors, reflected in the vertical and horizontal distribution of summer-fall temperature, salinity and dissolved carbon properties, can lead to substantial ecological differences and complexity over short (~20 km) spatial scales. In particular, the distribution of summer waters from the Bering Sea and cold, salty bottom waters (established by sea-ice formation during the previous winter) exerts an important influence on the pelagic components of this ecosystem. Consequently, large inter-annual variations in winds, summer sea-ice extent, and Bering Strait transport can lead to correspondingly large inter-annual differences in the distribution and abundance of zooplankton, planktivorous seabirds, pelagic-feeding marine mammals, and low-pH bottom waters.