Eutrophication can produce many undesirable effects in coastal systems.
Alternatively, reductions in the abundance and composition of predator populations can also produce profound effects in aquatic systems. Monthly determinations of water column nutrients and chlorophyll a, along with measurements of the biomass and abundance of leaf epiphytes and seagrass production, biomass and shoot and leaf densities will be used to evaluate the relative effects of manipulating nutrient supply and altering food web structure. The latter is of particular importance, as it is increasingly recognized that our approach to understanding and managing the health of coastal ecosystems must include the simultaneous assessment of multiple stressors. This is particularly true, for example, in areas like the Chesapeake Bay or the Florida Keys, where very expensive nutrient reduction plans are being implemented or contemplated in hopes of permitting the reestablishment of seagrass beds. If food web effects due to fishing activities are significantly involved in seagrass losses in such areas, costly reductions in nutrient supply may not ensure the return of seagrass habitat.