However, assembling a suite of models, each tailored to deal with a different class of waterbody, may offer greater promise and provide coastal managers with more options. In many cases, what is needed is a better or more accurate understanding of how a small number of parameters affect the response of an estuary, rather than a more complex or robust model.
Conduct periodic, comprehensive assessments of coastal environmental quality. Lack of detailed study of the scope and impacts of nutrient over-enrichment limits our capability to understand impacts, predict trends, or determine if management actions are having the intended results. The nation needs to conduct a periodic (i.e., every 10 years), comprehensive reassessment of the status of nutrient problems in coastal waters, similar in scope to the NOAA National Estuarine Eutrophication Assessment (Bricker et al. 1999).
Expand and target research to improve understanding of the causes and impacts of nutrient over-enrichment. In particular, work is needed to study atmospheric deposition of nutrients, including sources, fate, transport, and impacts. Research is also needed to understand the relative roles of nitrogen and phosphorus in different freshwater and marine systems, and how these may change seasonally. Better understanding is needed of the role of specific nutrients and conditions in causing harmful algal blooms and the implications for all levels of the food web, from fish to humans. Finally, research is needed that increases our understanding of the effects of nutrient inputs on economically valuable resources (e.g., oysters, fish stocks, etc.) so that we are better prepared to do the analyses necessary to compare costs and benefits and set acceptable restoration goals.
In general, the committee believes the most appropriate approaches for combating nutrient over-enrichment and its impacts will involve a combination of voluntary and regulatory mechanisms. Flexibility is key, especially for local problems, if programs are to achieve goals at minimal cost. It will be important to use an adaptive management approach, so that lessons are learned as techniques are tried and adjustments are made in response to improved information. Other regions or localities can learn from success and failure in particular situations. Because nutrient over-enrichment is caused by “upstream” activities, it may prove necessary to form commissions or other multi-jurisdictional groups to involve diverse groups of stakeholders.