Collaborative Research: Impact of sea-ice on bottom-up and top-down controls on crustacean zooplankton and the mediation of carbon and energy flow in the eastern Bering Sea

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Funds are provided to examine the impact of sea ice on the distribution and abundance of zooplankton, and how they are partitioned among top predators. To this end, new and historical data will be used to test a series of hypotheses and answer questions relating to bottom-up and top-down control of large crustacean zooplankton and their impact on the flow of carbon and energy in the ecosystem. From the examination of these hypotheses, new mechanisms will be derived and old ones re-evaluated. Existing numerical models will be used to assess the relative importance of these mechanisms. Existing conceptual models will be tested, and new conceptual models of carbon and energy flow will be developed. Such a study of the eastern Bering Sea shelf ecosystem is timely. Some of the most direct effects of changing climate will be on sea-ice - its extent, duration, timing of retreat, and inter-annual variability. Sea ice in turn controls ocean temperature/salinity, timing of the spring phytoplankton bloom and thus the extent of export/remineralization of fixed carbon. Crustacean zooplankton can be a choke-point in the flow of carbon and energy through the food chain.The Bering Sea ecosystem provides roughly half the commercial seafood landings in the United States, as well as significant resources for subsistence fishermen. Major fluctuations in these stocks have occurred in the past and been associated with climate variations. Improved management of these important fisheries should be enabled by the understanding derived from this project.