Report of the

U.S. GLOBEC Georges Bank

Science Meeting

18 - 20 November 2003, Rhode Island


Cover Page




Presentation Abstracts

Poster Presentations

Appendix I: Agenda

Appendix II: List of Participants

Appendix III: List of Planned Publications

Physical and Biological Controls on Calanus finmarchicus in the Georges Bank Region: an Adjoint Data Assimilation Approach

Li, X.1, D. McGillicuddy1
1AOPE Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543

An adjoint data assimilation approach is used to explore the physical and biological controls on Calanus finmarchicus C2 to C5 copepodites in the Georges Bank region. Monthly climatological distributions of Calanus finmarchicus from the GLOBEC Georges Bank Broad-Scale Surveys are assimilated into a coupled physical-biological model. The model is run over the observational period between January and June. The inversion quantifies the supply stock of these Calanus finmarchicus copepodites to Georges Bank, the biological sources/sinks, and physical advective/diffusive transports of these animals near the Georges Bank region. Results show that the Scotian Shelf and Gulf of Maine are important source regions of C4 and C5 in late winter. Wilkinson Basin provides a continuous source of Calanus finmarchicus to Georges Bank during spring and early summer. The adjacent Georges Basin is a region of both source and sink. Generally, both biological gains/losses and physical advection are important for the observed distributions. Large seasonal and spatial variabilities are present in all the fields of the convergence of the advective/diffusive flux, as well as growth and mortality. During spring and early summer, biological production is the major contributor to the observed high abundance on the Bank. The decline of C2 and C3 abundances in May is a combined balance among biological processes and advection. The disappearance of C2 to C4 from the crest of the Bank in June is mainly a result of biological losses, while disappearance of C5 from the crest results from both biological loss and advection.

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