US-GLOBEC: NWA Georges Bank: Impacts of climate and basin-scale variability on the seeding and production of Calanus finmarchicus in the Gulf of Maine/Georges Bank region

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The processes linking the ecosystems of Georges Bank, Scotian Shelf, Slope Sea and Gulf of Main to climate variability-induced, basin-scale circulation changes caused by large-scale atmospheric effects such as the North Atlantic Oscillation (NAO) appear to occur over both multi-decadal and interannual time scales. This project aims to elucidate how these multi-year changes in circulation within the western North Atlantic basin affect C. finmarchicus, specifically its transport onto Georges Bank. This will be accomplished via a combination of numerical model simulations and observational data.Primary tasks include: (1) Setting up and running an individual based model (IBM) for the Northwest Atlantic, using physical fields corresponding to the high-NAO (1980-1993) and low-NAO (1962-1971) periods obtained from an ongoing eddy-resolving North Atlantic simulation to understand multidecadal variability of Calanus finmarchicus seeding and production in this region; (2) Performing eddy-resolving basin-scale model simulations during 1988-1999 starting from already existing high-NAO simulations (from an ongoing NASA project) and run the IBM to study the interannual variability of C. finmarchicus seeding and production in this region; (3) Analyzing long-term in-situ physical and biological datasets and satellite-derived sea surface temperature (SST) along with in-situ physical, biological, and chemical data collected during the GLOBEC core-measurement period (1995-1999) to validate the basin-scale physical and biological fields and develop a broader understanding of C. finmarchicus seeding and production; (4) Generating four-dimensional high-resolution (5-km) physical fields using basin-scale fields and available data during 1993-1999, and running a series of IBM simulations at higher resolution in order to address questions relating ecosystem variability in the study regions to the large-scale fluctuations of the NAO.Within the GLOBEC synthesis effort, this study will enhance the scientific understanding of large-scale climatic and basin-scale forcing on the regional ecosystem of the NWA/GB region. Two graduate students will be trained. Results will be disseminated in scientific publications and presentations at national conferences while model output and several value-added fields will be made available via a website linked to the GLOBEC Georges Bank website.