Winners of 2008 Tyler Environmental Prize announced

James Galloway described the 'nitrogen cascade' of ecological impacts from fertilizers and fossil fuels; Harold Mooney helped transform ecology into a global discipline

Two scientists who drew important links between local and global ecosystems --- a prescient explorer of nitrogen's wide-ranging impacts, and a central figure in the rise of international ecology -- will share the 2008 Tyler Prize for Environmental Achievement.

The award, consisting of a $200,000 cash prize and gold medals, will go to James Galloway, professor of environmental sciences at the University of Virginia, and Harold Mooney, professor of environmental biology at Stanford University.

On Thursday, April 10, at 2 p.m., Galloway and Mooney will deliver public lectures at the Davidson Conference Center of the University of Southern California, which administers the prize.

On Friday, April 11, at 7 p.m., the Tyler Prize executive committee and the international environmental community will honor the recipients at a banquet and ceremony at the Four Seasons Hotel in Beverly Hills.

When the acid rain crisis of the 1970s began easing due to better control of nitrogen and sulfur emissions, many ecologists moved to other research areas. Galloway knew better.

"He was one of the few in the U.S. who realized that critical issues remained unresolved, especially in the area of nitrogen deposition," wrote John Aber of the University of New Hampshire, one of several leading environmental scientists who supported Galloway's nomination.

"In this arena, Jim has truly become the national and international leader," Aber added.

Galloway and his colleagues wrote the key papers presenting the "nitrogen cascade," a flow chart showing the pervasive and persistent effects of reactive nitrogen on Earth's environment.

Nitrogen in its inert form is harmless and abundant in the atmosphere. But in recent decades, massive amounts of reactive nitrogen compounds, such as nitrous oxide, have been entering the environment. Most have come from the use of nitrogen-based fertilizer.

Galloway used the cascade image to describe the sequential impacts of reactive nitrogen. A nitrogen atom that starts out as part of a smog-forming compound may then be deposited in lakes and forests as nitric acid.

Carried out to the coast, the same nitrogen atom may contribute to red tides and dead zones. Finally, the nitrogen may be put back into the atmosphere as part of the greenhouse gas nitrous oxide.

"We're accumulating reactive nitrogen in the environment, and this is as much of a legacy as putting carbon dioxide in the atmosphere," Galloway said.

"The public doesn't know about nitrogen, but in many ways it's as big an issue as carbon, and due to the interactions of nitrogen and carbon, makes the challenge of providing food and energy to the world's peoples without harming the global environment a tremendous challenge."

Galloway and others have suggested possible approaches to minimizing nitrogen use, such as optimizing its uptake by plants and animals, recovering and reusing nitrogen from manure and sewage, and decreasing nitrogen-intensive livestock farming.