Joye, S. B.. The University of Georgia, mjoye@arches.uga.edu
, . B.. ,

 
SPATIO-TEMPORAL PATTERNS IN RATES OF BENTHIC NITRIFICATION AND METHANE OXIDATION IN GALVESTON BAY, TEXAS.
 
Rates of methane (CH4) oxidation and nitrification, two microbially-mediated, metabolically similar processes, were examined at stations along the salinity gradient in Galveston Bay, Texas, USA. In situ nitrification rates were determined in the field using benthic chambers and by using specific metabolic inhibitors in laboratory experiments. In situ CH4 oxidation rates were determined in the laboratory using a 14C-CH4 tracer. Potential (aerobic, NH3 or CH4 amended) nitrification and CH4 oxidation rates were determined in laboratory incubation experiments. In situ rates of nitrification and CH4 oxidation ranged between 0.5 - 5 and 2 - 15 mmol m-2 d-1, respectively. Potential nitrification and CH4 oxidation rates varied between 0 - 500 and 0 - 200 nmol (g wet sed)-1 hr-1, respectively. Seasonally, highest rates were observed in summer and fall while lowest rates were observed in winter, correlating well with seasonal changes in temperature and substrate concentration. Spatially, maximum in situ rates of both processes occurred at the freshwater site while potential rates were highest at intermediate salinity sites. Depth profiles of nitrification and CH4 oxidation illustrated that highest activities of both processes were positively correlated. Laboratory experiments suggest co-metabolism and competition for substrates influences rates of both nitrification and CH4 oxidation in this system.
 
Day: Friday, Feb. 5
Time: 09:45 - 10:00am
Location: Sweeney Center
 
Code: CS63FR0945S