Scientists believe about 300 times more carbon is stored in soils than is being put in the atmosphere in the form of C02, according to biology Assistant Professor Alan Townsend of the University of Colorado at Boulder. Each year soils release about 20 times more carbon than industrial activities through decomposition.

"Decomposition is primarily balanced by plant growth, but increasing nitrogen falling on ecosystems could change that balance," he said. The study shows tundra soils are unexpectedly sensitive to added nitrogen, bringing up the question of how increases in nitrogen throughout the world might affect C02 storage areas, or 'sinks,' on land," Townsend said.

A paper on the subject by Townsend, co-principal author Jason Neff of the U.S. Geological Survey in Denver, Scott Lehman, Joyce Turnbull and William Bowman from CU-Boulder and Gerd Gleixner from Germany's Max Planck Institute will appear in the Oct. 31 issue of Nature.

C02 in the atmosphere is believed to have risen by about one-third since the Industrial Revolution began in roughly 1760, contributing to a warming climate.

"The nitrogen deposited on land might act like fertilizer and cause plants to grow more, at least for a while, which would suck up some carbon from the atmosphere," said Townsend, an associate at CU-Boulder's Arctic and Alpine Research Institute, along with co-authors Lehman, Turnbull and Bowman. "But it also could cause soils to lose some of their carbon, which would add even more C02 to the atmosphere."

The study area was Niwot Ridge 35 miles west of Boulder, administered by INSTAAR and one of 20 Long-Term Ecological Sites in North America funded by the Natio
'"/>

Contact: Alan Townsend
alan.townsend@colorado.edu
303-492-6865
University of Colorado at Boulder
30-Oct-2002