The Impact of Scotian Shelf Water "cross-over" on the Plankton Dynamics on Georges Bank: A 3-D Experiment for the 1999 Spring Bloom

Chen C.1, R. Ji.2, P. J. S. Franks3, D.W. Townsend4, E.G. Durbin5, R. C. Beardsley6, and R.W. Houghton7
1School for Marine Science and Technology, University of Massachusetts-Dartmouth, New Bedford, MA 02744 2Department of Marine Sciences, University of Georgia, Athens, GA 30602 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

The 1999 March SeaWiFS images detected an intensive phytoplankton bloom on the southeastern flank of Georges Bank (GB). A 3-D coupled physical (FVCOM) and biological (9-component NPZD) model was applied to the Gulf of Maine/GB region to examine the impact of a Scotian Shelf Water "crossover" on the plankton dynamics on GB. Process-oriented modeling experiments show that the formation of the phytoplankton bloom on the southeastern flank of GB is related to 1) transport of the Scotian Shelf Water, 2) wind- and tidal-induced vertical mixing and surface cooling, and 3) the location of the salinity front. Under a condition with sufficient supplies of nutrients from the slope, the bloom could occur due to an in situ growth of phytoplankton near the slope where the stabilized salinity front is located. The model results suggest that an accurate simulation of the spatial distribution of temperature and salinity on GB and flow field across the Northeast Channel is a prerequisite for modeling the spring bloom over GB.

A powerpoint version and an html version of this presentation are available on-line.

(Note: Animations included in html versions of Powerpoint presentations will likely work with Internet Explorer but will not work with Netscape 7.x.