Spatial and temporal trends of dissolved nitrous oxide in the Lamprey River Watershed and controls on the end-products of denitrification

An understanding of the controls on the production of the greenhouse gas N2O is important to assess the atmospheric contribution of N2O from freshwater streams. Concentration and percent saturation of dissolved N2O were measured from March 2008 to February 2009 and were used as to measure the potential for streams in the Lamprey River Watershed to lose N2O to the atmosphere. Almost all streams were oversaturated most of the year, and though field concentrations of dissolved N2O did show trends with stream chemistry, it is possible that N2O is not only being produced within the streams themselves, but is entering the streams via groundwater and surface runoff. A controlled laboratory experiment was also conducted to determine controls on N2O and N2O production from denitrification. These controls were much more obvious than in the field study, suggesting that laboratory experiments may misrepresent field conditions.