Water quality in different bodies of water in a watershed will tell us "how we're doing". Is water quality good? Is it bad? Is it variable from season to season? Do we need to do anything about it? When we sample in the field, we measure water temperature, dissolved oxygen concentration, salinity, and acidity. We also bring water samples back to the Keck Lab to analyze for suspended sediment load, fecal coliform bacteria, and nutrient levels. Sediments, bacteria, and nutrients-specifically nitrogen-are the major contaminants found in the streams and lakes of local watersheds. These contaminants also are the pollutants that are in part responsible for declining fisheries productivity in Chesapeake Bay. If we don't want these pollutants in Chesapeake Bay, then we need to keep them out of the streams and lakes of our local watersheds (and all of the thousands of little watersheds that collectively make up the Chesapeake Bay watershed).