Biophysical Moorings on the Eastern Bering Sea Shelf: 15 Years of Observations

The southeastern Bering Sea shelf is one of the world's most productive marine ecosystems. This high latitude sea is characterized by high biological productivity and the seasonal presence of sea ice. Integrated ocean observations, from physical and atmospheric forcing to the distribution and abundance of top-level predators, is critical to investigating such marine ecosystems and the impact of climate change on them. To accomplish this, a series of biophysical moorings have been deployed at four sites along the center (approximately the 70 m isobath) of the broad (~500 km), eastern Bering shelf. They stretch ~800 km from M2 in the south to M8 in the north. The site at M2 has been instrumented for 15 years, while the other sites have been instrumented for 5-12 years. At each site, ocean temperature, salinity, nitrate, oxygen, chlorophyll fluorescence and currents are measured, and listening devices for marine mammals are also deployed. At the southern site, instruments that measure zooplankton biovolume provide important information on temporal variability of zooplankton. These biophysical moorings, coupled with extensive shipboard measurements, are being used to understand how this ecosystem is changing under the influence climate variability. These data have expanded our understanding of how ice modifies this ecosystem, from physical characteristics of the ocean and the timing of spring phytoplankton bloom to the distribution of fish and marine mammals. Distinct patterns in production (chlorophyll), zooplankton biovolume (copepods and euphausiids) and the occurrence of zooplankton predators (fin and right whales) are evident in the data and related to discrete features in the annual physical cycle. These data illustrate the capability and potential of integrated ocean observing systems (IOOS) to describe seasonal variability and linkages in a remote marine ecosystem.