The role of the atmosphere in coastal ecosystem decline—future research directions

Abstract

Current assessments of the role of atmospheric deposition in the declining health of aquatic ecosystems indicate that the atmosphere could account for as much as 30% to 40% of total external nitrogen loading to some coastal waters. All such assessments are uncertain and need to be refined. To focus attention on the problem as it affect eastern North American coastal waters, a series of interdisciplinary workshops has been conducted, bringing together scientists and regulators. The series started with a meeting at Mt. Washington, Maryland in 1994, with subsequent meetings at Warrenton, Virginia in 1995, and Raleigh, North Carolina in 1997. Although the workshops considered all nitrogen species, toxic chemicals, trace metals, precipitation chemistry, airborne aerosols, and supporting meteorological investigation, most of the discussion centered around the issue of nitrogen-species deposition. It was concluded that work is urgently needed to establish integrated monitoring stations to provide high quality deposition and watershed retention data within the catchment area to take spatial and temporal variability into account in atmospheric deposition models, to improve biogeochemical watershed models, especially from the perspective of biological utilization and cycling of deposited materials, to refine emissions inventories and projections on which scenario investigations are based, to enhance all ongoing data collection efforts, especially those related to specific process studies, and to improve spatial resolution by increasing the number of deposition measurement sites. An overall conclusion was that there must be a strong effort to include considerations of air pollution and atmospheric deposition in the water quality regulatory process. It was repeatedly emphasized that any new efforts should build on existing programs rather than risk new starts that compete with ongoing and already productive work.