Schultz, Jr., G. E.. College of William and Mary, School of Marine Science, gschultz@vims.edu
Ducklow, H. E.. College of William and Mary, School of Marine Science, duck@vims.edu

 
CHANGES IN BACTERIOPLANKTON METABOLIC CAPABILITIES ALONG A SALINITY GRADIENT IN THE YORK RIVER, VA, ESTUARY
 
Bacterial processing of autochthonous and allocthonous organic matter determines the extent of export of DOC and POC through estuaries to the coastal ocean. To further understand the nature and magnitude of this term, we examined bacterial community dynamics over seasonal and basin scales within the York River, VA, estuary. Bacterial abundance and production were measured monthly at six stations spanning the entire salinity gradient. Two opposing trends were consistently found: bacterial abundance increased from freshwater to the mouth of the river, while TdR incorporation rates decreased from freshwater to the mouth. These patterns imply a strong landward gradient in specific growth rates and present quite a puzzle. Changes in metabolic capabilities of bacterial communities along the salinity gradient may affect the extent of DOC and POC export and may be part of the solution to this puzzle. We attempted to quantify differences in bacterial community structure through the use of BIOLOG plates. BIOLOG plates were inoculated bi-monthly at the six stations. Plates were incubated at in situ temperatures, and color development was monitored with a spectrophotometer. Principle component analysis shows clear differences in the patterns of community metabolic capabilities along the salinity gradient. Rates of color development were also measured and mimic the pattern of a strong landward gradient in specific growth rates. This research was supported by ONR Contract N00014-93-1-0986.
 
Day: Wednesday, Feb. 3
Time: 08:45 - 09:00am
Location: Hilton of Santa Fe
 
Code: CS60WE0845H