The primary objective of the proposed research is to assess the linkage between upland ground water and its discharge into an adjacent tidal creek and marsh at an agricultural area on the Eastern Shore of Virginia. Stable Isotopic analysis of ground water nitrate and ammonium will be utilized to determine the source of inorganic nitrogen and to identify any chemical transformations among nitrogen species that occur during transport. The results from this study will enable an evaluation of the relative importance of geomorphological factors, and the hydraulic and chemical properties of sediments, have in controlling mechanisms of nutrient cycling.