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Ecological Integrity

The Clean Water Act stipulates that all U.S. waters (fresh and salt) must be fishable and swimmable. More specifically, this legislation charges that EPA, "...preserve and restore the physical, chemical, and biological integrity of the Nation's waters." As reflected in the language of this law, the public wants, and EPA develops regulations to protect and restore the "health and integrity" of the nation's coastal ecosystems. Although we know that the condition of any ecosystem is the result of the cumulative effects of natural and anthropogenic influences, terms like "health" and "integrity" are not well-defined, scientifically measurable attributes of marine systems. An ecosystem, by definition, is an intricate combination of organisms interacting with their physical and chemical environments, functioning together as an ecological unit. The goal of this research is to develop the theoretical framework and the ecological indicators necessary to characterize, quantify, and predict the "health and integrity" of Atlantic Coast estuarine and marine ecosystems. The work focuses at the management unit scale of watershed sub-basins. The results of this research program will provide the critical scientific information necessary for environmental managers to make the most informed decisions concerning ecological assessments of estuarine and marine systems by providing measurement tools and indicators necessary to: 1) assess the current "health state" of their respective waterbodies, 2) determine if those conditions fit within the "normal" boundaries for that use attainability category, and 3) determine if the estuarine system is changing to a different "health state." Society then can decide if and how much it is willing to invest in maintaining a healthy waterbody, preventing degradation, or remediating a currently degraded condition to a more "normal, healthy" condition for that use class.

This theme employs combines a case-study approach with field and laboratory studies. The effort is allocated among three multidisciplinary research teams. The primary focus of the first team will be to quantify and characterize the biological, chemical, and physical characteristics of the field estuarine systems, including documenting the spatial extent of habitats in ecological systems. This includes using and evaluating traditional measurements (e.g. benthic communities, productivity, chemical concentrations, bathymetry, flushing rate, etc.) and experimental designs (e.g. biased vs. unbiased sampling), as well as developing new techniques. Another aspect of system characterization includes an historical reconstruction component to both quantify past inputs which have contributed to the cumulative effects on the system as well as possible reference states prior to anthropogenic impacts. These data will be used to identify natural and anthropogenic stressors within a system and to develop higher level assessment endpoints of ecosystem health and integrity.

The second team focuses on understanding the relationships between natural and anthropogenic stressors and the health and integrity endpoints developed. This will include the use of laboratory microcosms to provide the level of control necessary to elucidate these relationships. Numerical simulation models will be used, as necessary, to explore cause-effect relationships. Another important aspect of this research will be to define the temporal scales over which effects from stressors occur.

A third team deals with modeling the effects of natural and anthropogenic stressors on ecosystem health and integrity endpoints. These models will be used to establish the "normal" boundaries for selected use class designations. Predictions of health and integrity for various use classes then will be verified in the field. In addition, this team will be responsible for developing techniques to incorporate existing data on estuarine characteristics, land-use, etc. and extrapolate these findings to watershed-level scales.

The types of research products from this theme include:

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