Report of the

U.S. GLOBEC Georges Bank

Science Meeting

18 - 20 November 2003, Rhode Island

 


Cover Page

Acknowledgements

Introduction

Narrative

Presentation Abstracts

Poster Presentations

Appendix I: Agenda

Appendix II: List of Participants

Appendix III: List of Planned Publications


Modeling Studies of the Physical-Biological Processes Controlling Spring Bloom Dynamics on Georges Bank: 1-D and 2-D Experiments
Ji, R.1, C. Chen2, P. J. S. Franks3, D. W. Townsend4, E.G. Durbin5, R. C. Beardsley6, and R. W. Houghton7
1Department of Marine Sciences, University of Georgia, Athens, GA 30602
2School for Marine Science and Technology, University of Massachusetts-Dartmouth, New Bedford, MA 02744
3Marine Life Research Group, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0218
4School of Marine Sciences, 5741 Libby Hall, University of Maine, Orono, Maine 04469
5Graduate School of Oceanography, University of Rhode Island, South Ferry Rd, Narragansett, RI 02882
6Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543.
7Lamont Doherty Earth Observatory of Columbia University, Palisades, NY 10964

A coupled biological-physical model has been developed for the Gulf of Maine (GOM) /Georges Bank (GB) region. The biological model, based on nutrient and plankton features observed on GB, consists of 9 compartments: nutrients (nitrate, ammonia and silicate), phytoplankton (large and small size groups), zooplankton (large and small size groups), detrital organic nitrogen and silicon. The physical model for 1-D and 2-D experiment is ECOM-si, which is driven with tidal forcing, wind stress and heat flux. The 1-D model results show that the physical-biological processes controlling spring bloom dynamics over GB varies with water depth. In the shallow and well-mixed regions, the timing of the spring bloom is sensitive to light intensity and the light attenuation coefficient, while the magnitude is regulated by the initial nutrient concentration and zooplankton grazing pressure. In the deeper regions, the seasonal onset of stratification directly attributes to the timing of the spring bloom. The 2-D model results indicate that the spring bloom dynamics in the shallow and well-mixed area of GB are very similar to the 1-D situation. A 'second' bloom can occur near the tidal mixing front area due to the seasonal onset of stratification. The spring bloom in the stratified region seems to be sensitive to vertical stratification, especially at the transition time during late spring.

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