Rr. Hood et al., Modeling particles and pelagic organisms in Chesapeake Bay: Convergent features control plankton distributions, J GEO RES-O, 104(C1), 1999, pp. 1223-1243
A two-dimensional Lagrangian particle trajectory model is described and use
d to study how surface currents transport particles and, by analogy, plankt
on in Chesapeake Bay, United States. It is shown that persistent patches of
high particle concentration develop in well-defined regions along the east
ern shore and in the lower reaches of some western shore tributaries due to
a combination of passive accumulation of particles in areas where the flus
hing rate is low and convergence. In the model the highest particle concent
rations in the Chesapeake consistently develop in the lower bay (latitude 3
7.1 degrees-37.7 degrees N). in two specific regions near the shore of Cape
Charles where convergence and downwelling occur. It is shown that one of t
hese is associated with a strong and persistent, residual cyclonic eddy loc
ated over an abrupt change in bottom topography. Recent bay wide held surve
ys reveal that various planktonic groups, including phytoplankton, zooplank
ton, and bay anchovy eggs and larvae, have maximum abundances in the vicini
ty of this eddy. It is argued that these convergent areas are important fea
tures that have a strong influence an plankton distributions and that they
provide consistently high food concentrations for higher trophic levels.