Choi, K. KH. Dept of Ocean, Earth and Atomospheric Sciences / Old Dominion University, Kchoi@odu.edu
Drake, L. L. Dept of Ocean, Earth and Atomospheric Sciences / Old Dominion University, Ldrake@odu.edu
Locarnini, R. R. Center for Coastal Physical Oceanography / Old Dominion University, ricardo@ccpo.odu.edu
Valle-Levinson, A. A. Center for Coastal Physical Oceanography / Old Dominion University, arnoldo@ccpo.odu.edu
Dobbs, F. F. Dept of Ocean, Earth and Atomospheric Sciences / Old Dominion University, fdobbs@odu.edu

 
HYDROGRAPHIC INFLUENCE ON BACTERIOPLANKTON DYNAMICS AT THE ENTRANCE OF CHESAPEAKE BAY
 
Bacterioplankton inventories and processes were compared to hydrographic conditions at the entrance to Chesapeake Bay. At five stations, bacterioplankton samples from surface and bottom water were collected monthly from February 1996 to present. Along-transect spatial variability of bacterial measures usually was smaller than seasonal variability. Bacterial abundance, production, and specific growth rate generally increased with increasing water temperature, but none of these properties was related to concentrations of chlorophyll a. Bacterial abundance and production were higher in surface water than bottom water principally during summer (water temperature >20oC), concomitant with strong water-column stratification induced by the combined influences of salinity and temperature. In other seasons, abundance and production were higher in bottom waters, in association with vertical mixing and resuspension of bottom sediments. Specific growth rate either decreased or was constant from early to late summer, indicating that substrate supply limits heterotrophic bacterial production. There were large interannual differences in this trend, however; summertime bacterial production was substantially lower in 1997 than in 1996 or 1998, as was river discharge. Substrate supply, therefore, may regulate interannual variability in bacterioplankton production in this environment.
 
Day: Wednesday, Feb. 3
Time:
Location: Sweeney Center
 
Code: CS60WE0379S