SS2.02 Biogeochemical Process at the Sediment-Water Interfaces
Date: Tuesday, June 11, 2002
Time: 4:00:00 PM
Location: Carson B
NeelyMB, University of South Florida, St. Petersburg, USA,
Vargo, G, A, University of South Florida, St. Petersburg, USA,
The research objective is to address the relationship between benthic microalgal communities and sediment nutrient flux in Florida Bay. Studies were conducted at three locations, bimonthly from May, 2000 to the present. Sediment chlorophyll a values were an order of magnitude higher than water column values. Inorganic P flux measurements have been variable, but there is generally an increase in P concentration in dark chambers throughout the incubation, especially during the afternoon hours when primary productivity is highest. Light chambers generally exhibited no P flux but uptake did occur. Total dissolved phosphorus (TDP) flux from the sediment ranged from -4.9 to 4.29 uM m-2 h-1. Soluble reactive phosphorus (SRP) values were generally much less than TDP, and ranged from -0.8 to 13.79 uM m-2 h-1. Initial water column dissolved organic nitrogen (DON) values ranged from 1.55 to 9.05 uMl-1 and averaged ~4 uMl-1, but DON flux from the sediment during the incubations was minimal. Florida Bay sediments can be a viable nutrient source for benthic and pelagic microalgae, however, phosphate flux is complicated by sediment chemistry.