and response to proposed air quality controls. EPA should also consider expanding TIME/LTM to include monitoring of acid-sensitive biological indicators at a subset of sites. This would allow managers to assess linkages between changes in the acid-base status of surface waters and biological responses to changing chemical conditions.
11. Improve methods and facilities on regional scales to evaluate the status, trends and response to controls on atmospheric sources of nitrogen (see, for example, ESA [1997b]).
There is a need for basic estimates of organic nitrogen deposition rates and loadings, and for linking delivered atmospheric loads to sources. For example, the effects of forest management and agricultural practices on delivery of nitrogen to coastal waters should be examined. Assessments of atmospheric deposition profiles are needed for all key estuarine/coastal systems along the Atlantic and Gulf coasts. These profiles should be developed using a consistent set of methodologies or tailored to specific regions using a common base of information.
12. Expand the existing estuarine monitoring programs (National Estuaries Program and National Estuarine Standards Reserve System) to address existing gaps in knowledge of effects of atmospherically deposited chemicals in the coastal zone.
Where atmospheric deposition data are lacking in some systems, expansion would have to include wet and dry deposition measurements (requiring significant funding and technical expertise). Monitoring at these sites should be expanded to quantify mass inflow of reactive nitrogen and other pollutants (for example, mercury) that are derived from atmospheric sources. The monitoring program should be coordinated with measurements of estuarine conditions, including nitrogen species, dissolved oxygen, chlorophyll, and sea grass biomass. A second option is to foster the formation of integrated estuarine studies (for example, MODMON, the Neuse River Estuary Modeling and Monitoring program at the University of North Carolina (at MODMON 2001). Using either approach, the monitoring program should be linked to modeling efforts to simulate emissions and atmospheric deposition and the transport and fate of atmospherically derived pollutants within watersheds and estuarine ecosystems.