Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions

The Ecological Society of America (ESA), the nation's leading professional society of ecological scientists, is an essential source of information for those addressing the many complex tasks associated with watershed management. Since 1997, Issues in Ecology, has been an especially useful resource for citizens, resource managers, policymakers, and others designing and implementing watershed approaches to environmental management. Each Issues in Ecology paper is designed to report, in language understandable by non-scientists, the consensus of a panel of scientific experts on issues relevant to the environment. 

Number 15 (Winter 2012): Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions

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  Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions

  by Eric A. Davidson, Mark B. David, James N. Galloway, Christine L. Goodale, Richard Haeuber, John A. Harrison, Robert W. Howarth, Dan B. Jaynes, R. Richard Lowrance, B. Thomas Nolan, Jennifer L. Peel, Robert W. Pinder, Ellen Porter, Clifford S. Snyder, Alan R. Townsend, and Mary H. Ward

  Summary

  It is not surprising that humans have profoundly altered the global nitrogen (N) cycle in an effort to feed 7 billion people, because nitrogen is an essential plant and animal nutrient. Food and energy production from agriculture, combined with industrial and energy sources, have more than doubled the amount of reactive nitrogen circulating annually on land. Humanity has disrupted the nitrogen cycle even more than the carbon (C) cycle. We present new research results showing widespread effects on ecosystems, biodiversity, human health, and climate, suggesting that in spite of decades of research quantifying the negative consequences of too much available nitrogen in the biosphere, solutions remain elusive. There have been important successes in reducing nitrogen emissions to the atmosphere and this has improved air quality. Effective solutions for reducing nitrogen losses from agriculture have also been identified, although political and economic impediments to their adoption remain. Here, we focus on the major sources of reactive nitrogen for the United States (U.S.), their impacts, and potential mitigation options.

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