Nitrogen Dynamics in the Spring Creek Watershed: Evaluating Stream Retention of Point and Non-Point Loadings

Cultural eutrophication is a problem of epidemic proportion in the United States, and this issue is particularly pronounced in water bodies that are in close proximity to the demands of a growing human population. Elevated material loading from changing land-use (urban and agricultural practices) has had a measurable effect on aquatic ecosystems throughout the state of Pennsylvania, where more than 2,500 miles of native streams receive some degree of impact.

Identification of the source of nitrate in streams can be facilitated by using 15N and 18O stable isotope signatures along with inorganic water chemistry. Characterization of stable isotopes signatures can be used to estimate nitrate loads from point sources such as fish hatcheries and sewage treatment plants and non-point sources such as septage, urban runoff, agricultural lands, and atmospheric deposition.

This project supports a new faculty member and several students in the Fisheries
Program at the Penn State-University Park campus proposing to look at how nitrogen
with varying isotope composition within a large mixed landuse watershed affects the
trophic transfer of nitrogen in the stream biological community.