You are here:
SENSITIVITY OF NITROGEN CONCENTRATIONS IN ESTUARIES TO LOADING AND WATER RESIDENCE TIME: APPLICATION TO THE POTOMAC ESTUARY
Citation:
Dettmann, E H. AND H A. Walker. SENSITIVITY OF NITROGEN CONCENTRATIONS IN ESTUARIES TO LOADING AND WATER RESIDENCE TIME: APPLICATION TO THE POTOMAC ESTUARY. Presented at 2nd International N Conference, Potomac, MD, October 14-16, 2001.
Description:
We use a simple nitrogen budget model to analyze concentrations of total nitrogen (TN) in estuaries for which both nitrogen inputs and water residence time are correlated with freshwater inflow rates. While the nitrogen concentration of an estuary varies linearly with TN loading rate, its dependence on residence time is more complex. For a fixed mass-loading rate of nitrogen, the concentration of TN in estuaries with residence time less than a month increases nearly linearly with residence time. Concentrations increase more slowly as residence time grows further, and are essentially constant for residence times greater than approximately 10 months. This nonlinear behavior affects the relative sensitivities to TN loading of estuaries with different. residence times, and year-to-year variation in the sensitivity of a single estuary with fluctuating freshwater inputs.
We examine the effects of interannual changes in water and nitrogen inputs to the Potomac Estuary. Analysis with the model shows that although reduced residence time lessens the effect of larger nitrogen inputs in wet years, the net effect on the estuary is still an increase in the concentration of total nitrogen.