Assessment of Nitrogen Loads to Aquatic Systems

Estimates of the contributions of atmospheric nitrogen deposition to Chesapeake Bay, Galveston Bay, and Tampa Bay are reported. The estimates are based on a refinement of a methodology developed by the Environmental Defense Fund in a 1988 study of Chesapeake Bay. The three-embayment study employed a spreadsheet methodology that produced estimates of nitrogen loadings from various nitrogen sources found in each of the study areas. Sensitivity analysis showed that atmospheric deposition has a significant effect on the nitrogen loadings delivered to the aquatic systems. More than 40% of the total nitrogen loads to the three systems resulted from nitrogen deposition