EFFECTS OF ORGANIC CARBON LOADING ON COUPLED NITRIFICATION/DENITRIFICATION IN ESTUARINE SEDIMENTS

Microbial denitrification is an important geochemical process in the removal of excess nitrogen species from coastal marine systems. The presence of excess nutrients within estuarine environments is responsible for the development of eutrophic conditions and subsequent growth in pelagic biomass. The response of benthic microbial communities to simulated algal bloom conditions were studied using laboratory sediment incubations. Utilizing 15N tracer techniques, rates of coupled nitrification/denitrification and nutrient flux were measured through various amounts of organic carbon additions. Initial results suggest that influx of organic carbon has a rapid effect on microbial metabolism within the system, as benthic response varies with the amount of organic carbon amended to the sediment. Subsequent increases in microbial O2 consumption have immediate impacts on benthic nitrogen cycling and resulting removal of nitrogen species from the marine environment.