James N. Galloway,^* Ellis B. Cowling,^** Sybil P. Seitzinger,^*** Robert H. Socolow<sup>****


*</sup>James N. Galloway is professor of environmental sciences at the University of Virginia, USA. His research on biogeochemistry includes the natural and anthropogenic controls on chemical cycles at the watershed, regional and global scales. His current research focuses on beneficial and detrimental effects of reactive nitrogen as it cascades among environmental reservoirs in the atmosphere and biosphere of the Earth. His address: Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22903, USA. jng@virginia.edu
^**Ellis Cowling is University Distinguished Professor At-Large at North Carolina State University. His interests in nitrogen began with his doctoral dissertation research on Nitrogen in Forest Trees and Its Role in Wood Deterioration at the University of Uppsala, Sweden and has continued in his leadership roles in the US National Acid Precipitation Assessment Program and the Southern Oxidants Study. His address: North Carolina State University, Raleigh, NC 27605, USA. ellis_cowling@ncsu.edu
^***Sybil Seitzinger is director of the Rutgers/NOOA Cooperative Marine Education and Research Program at Rutgers University, and on the faculty in the Institute of Marine and Coastal Sciences. Her research addresses sources, effects and fate of nitrogen in aquatic ecosystems. Her current research activities include dissolved organic nitrogen/chemical characterization, inputs, and bioavialability in aquatic ecosystems; denitrification in rivers, estuaries and continental shelves; and global modeling of N transport by world rivers to coastal ecosystems. Her address: Rutgers University, New Brunswick, NJ 08901, USA. sybil@imcs.rutgers.edu
^****Robert H. Socolow is professor of Mechanical and Aerospace Engineering (MAE) at Princeton University. He is the co-principal investigator of Princeton University's new Carbon Mitigation Initiative, a coordinated research program in environmental science, energy technology, hydrology, and economics. From 1979 to 1997, he directed the Center for Energy and Environmental Studies. He teaches in MAE and in the Woodrow Wilson School of Public and International Affairs. Socolow is one of the founders of the new research approach known as industrial ecology and has explored the industrial flows of nitrogen and lead from this perspective. Socolow is the editor of Annual Review of Energy and the Environment. He served on the Board of Directors of the National Audubon Society from 1992–1999. He was a member of the Advisory and Selection Committee for the Pew Scholars Program in Conservation and Environment, 1989–1992. He is a fellow of the American Physical Society and the American Association for the Advancement of Science. His address: Guyot 139, Princeton University, Princeton, NJ 08544, USA. socolow@princeton.edu.