10.3 Managing eutrophication

10.3 Managing coastal eutrophication under hydrologically-variable conditions

Integrated monitoring, research, and assessment are essential ingredients for a nutrient management programs in coastal systems affected by large-scale climatic and hydrologic variability. These programs should address the following questions:

• What type of assessment program is necessary and sufficient to adequately address the full range of ecosystem nutrient and habitat impacts resulting from major storms?
• What are the specific issues that are unique to monitoring on the short-term episodic and longer-term chronic event scales?

Monitoring and assessment should be able to answer the following questions:

• How far away from `normal' conditions was the system changed by climatic events?
• To what extent do these systems recover? What conditions are required for recovery?
• Are there permanent changes to the ecosystem, and what are they?
• How do human activities affect recovery?
• Are any of the changes (short-term or permanent) detrimental to human use and resources?

Lessons learned from the 1999 hurricanes that struck coastal North Carolina stress the need for long-term monitoring and assessment. These assessments must be able to detect and quantify these events over appropriate spatial and temporal scales, have realistic and sustainable efforts and financial resources, and achievable assessment criteria and goals. Important features of a long-term monitoring and assessment program include:

• Sampling to detect 1) trends, 2) changes in state equivalent to a step function, and 3) consequences of infrequent, but large-scale events.
• Both a routine monitoring and event-response components.
• Spatially- and temporally-extensive monitoring of key environmental variables, using continuous and time-integrative sampling of water quality, productivity and turbidity, possibly making use of satellite- and aircraft-remote sensing, large-scale, long term, real time monitoring using existing infrastructure such as bridges, platforms, commercial and government vessels, ferries. ([63]: www.ferrymon.org)
• Measurement of water quality and habitat responses using meaningful, sensitive and easily-deployed indicators of environmental stress.
• Assessment of sediments. Sediments contain a wealth of paleo-climate and paleo-sea level information for the past 10,000 years of coastal history.
• Aggregation of meteorological data on storm paths, winds, rainfall and flooding to provide a quantitative context for catastrophic storms.
• Assessment of effects of hydrologic, chemical and sediment loading on biotic communities impacting production, nutrient cycling, finfish and shellfish habitats, including water column, salt marsh, seagrass, and open sediment habitats, including:
  • The response of phytoplankton, associated nutrient cycling and grazing communities to storm-related physical-chemical perturbations.
• Fish community behavioral, physiological and health responses to variation in water depth, salinity, temperature and dissolved oxygen.
• Analysis of historical and contemporary data on fisheries landings and how landings respond to intense storm activity.

We may need to reevaluate the relationship between human activities in coastal watersheds and their effects on water quality and fisheries under conditions of more frequent storm events.

A vital component of an effective and broadly-utilized integrated assessment program is cooperation and coordination among state, federal and private research and monitoring entities. The North Carolina 1999 hurricane experience proved that a strong working relationship among these entities was essential for sharing resources and expertise and utilizing research aimed at understanding and managing a large system impacted by interacting human and climatic forcing features. Cross-cutting multi-disciplinary, multi-agency approaches and analyses provide the necessary broad perspective that is needed to assess ecological change in a system that simultaneously affects and is affected by human economic, cultural and activities and values.

Synthesis and modeling of watershed, water quality, habitat and fisheries effects of intense storms is a key component of an integrated assessment program and is an important tool for synthesizing information and providing options for environmental management. Extension of model predictions to cover over a wide range of infrequent and extreme conditions and validation of those predictions is both a challenge to, and requirement of, an effective assessment program. In lieu of that, models become minimally usable for understanding these macro-events. The challenge to simulating effects of macro storm events is to find ways to quickly integrate the results of various independent models to aid in the scientific and management response to these events.

10.3 Managing eutrophication