Understanding the relationship between ice, primary producers, and consumers in the Bering Sea

Abstract

Technology has progressed to the level of allowing for investigations of trophic level interactions over time scales of months to years which were previously intractable. A combination of active and passive acoustic technology has been integrated into sub-surface moorings on the Eastern Bering Sea shelf, and seasonal transition measurements were examined to better understand how interannual variability of hydrographic conditions, phytoplankton biomass, and acoustically derived consumer abundance and community structure are related. Ocean conditions were significantly different in 2012 compared to relatively similar conditions in 2009, 2010, and 2011. Differences were largely associated with variations in sea ice extent, thickness, retreat timing, and water column stratification. There was a high degree of variability in the relationships between different classes of consumers and hydrographic condition, and evidence for intra-consumer interactions and trade-offs between different size classes was apparent. Phytoplankton blooms in each year stimulated different components of the consumer population. Acoustic technology now provides the opportunity to explore the ecosystem dynamics in a remote, ice-covered region that was previously limited to ship-board measurements during ice-free periods. The new knowledge we are gaining from remote, long-term observations is resulting in a re-examination of previously proposed ecosystem theories related to the Bering Sea.