The Daily Bulletin Archive

Please join the Biology Department and the Great Lakes Center for the seminar "Nitrogen Cycling in Stream Ecosystems," presented by Jonathan O'Brien, assistant professor in the Department of Biology at Canisius College, on Monday, October 29, from 3:00 to 4:15 p.m. in Bulger Communication Center 424. All students, staff, and faculty are welcome.

Abstract
The expansion in the extent and intensity of human land use has led to increased concentrations of anthropogenic nitrogen (N) in streams and rivers, usually as nitrate. These increased N loads can result in eutrophication, the formation of harmful algal blooms and hypoxia in recipient freshwater and coastal ecosystems. In-stream N retention has the capacity to alter the timing and quantity of N transported to downstream ecosystems; however, the efficiency of N retention by streams decreases as nitrate concentrations increase and the majority of N is temporally retained through assimilation, rather than removed through denitrification. This seminar will highlight a series of experiments to explore the fate of N following assimilation and determine the mechanisms behind the loss of retention efficiency. We will also examine potential management strategies to increase in-stream nutrient retention, including the use of aquatic plants to enhance nutrient assimilation and organic matter additions to enhance N removal through denitrification.