Contact:
Jennifer Zelenke
Horn Point Environmental Lab
P.O. Box 775
Cambridge, MD 21613
zelenke@hpel.umd.edu
Despite intense scientific and legislative attention in recent years, the role of tidal marshes in the nutrient budgets of the Chesapeake Bay remains unknown. The purpose of our study was to determine if the burial of nitrogen and phosphorus was quantitatively important to the nutrient balance of the Patuxent River, a region which has historically experienced high N and P concentrations and loading rates. Using 210Pb-derived sedimentation rates and sediment nutrient concentrations at fifteen sites, we found sediment burial rates from 100 to 8600 g m-2 y-1 , N burial rates of 1 to 105 g m-2 y-1, and P burial rates of 0.05 to 6.1 g m-2 y-1. Phosphorus occurred primarily in inorganic forms. When integrated over the marsh area, burial can represent as much as 25% and 21% of the sum of total N and P inputs respectively. This study suggests that tidal fresh and brackish marshes in the upper parts of subestuaries may provide important water quality benefits to the lower estuary.