Assessing the nitrogen processes of a freshwater tidal estuary through microbial community and nutrient composition

Estuaries mitigate the effects of anthropogenic pollution, specifically nitrogen compounds. Critical to estuarine function is the composition of the microbial community. I assessed the temporal and spatial changes in microbial community diversity and nutrient concentrations of Jug Bay, an estuary of the Patuxent River, MD. I hypothesized that the diversity of the microbial community, with respect to the nitrogen cycle, will vary depending on vegetation and season. Sediment and water column samples were taken from five different vegetated sites during May, July, and October 2006. Denaturing gradient gel electrophoresis (DGGE) assessed community diversity using 16S rRNA primers for nitrifyers and the functional gene primers nirK and nosZ for denitrifiers. DGGE results show unique microbial strains to each vegetated site and strains that are present at all sites. Nitrifyer diversity was seasonally dependent while denitrifier diversity was spatially dependent. This research indicates a complex interaction between microbial communities and environmental conditions.