Link discovered between carbon, nitrogen may provide new ways to mitigate pollution problems

University of Colorado at Boulder: A new study exploring the growing worldwide problem of nitrogen pollution from soils to the sea shows that global ratios of nitrogen and carbon in the environment are inexorably linked, a finding that may lead to new strategies to help mitigate regional problems ranging from contaminated waterways to human health.

The University of Colorado at Boulder study found the ratio between nitrates -- a naturally occurring form of nitrogen found in soils, streams, lakes and oceans -- and organic carbon is closely governed by ongoing microbial processes that occur in virtually all ecosystems. The team combed exhaustive databases containing millions of sample points from tropical, temperate, boreal and polar sites, including well-known, nitrogen-polluted areas like Chesapeake Bay, the Baltic Sea and the Gulf of Mexico.

"We have developed a new framework to explain how and why carbon and nitrogen appear to be so tightly linked," said CU-Boulder doctoral student Philip Taylor, lead author on the new study. "The findings are helping us to explain why nitrate can become so high in some water bodies but remain low in others."

…While the vast majority of nitrogen gas is abundant in the atmosphere, it is nonreactive and unavailable to most life, said Townsend. But in 1909 a process was developed to transform the nonreactive gas into ammonia, the active ingredient of synthetic fertilizer. Humans now manufacture more than 400 billion pounds of fertilizer each year -- much of which migrates from croplands into the atmosphere, waterways and oceans -- creating a suite of environmental problems ranging from coastal "dead zones" and toxic algal blooms to ozone pollution and human health issues.

…"The bottom line is that if there is sufficient organic carbon present, it keeps the nitrates at a low level," said Townsend. "By using available data, we can now make more accurate evaluations of when and where nitrate pollution may pop up." In the February 2010 issue of Scientific American, Townsend and co-author Robert Howarth of Cornell University wrote that "a single new atom of reactive nitrogen can bounce its way around these widespread environments, like a felon on a crime spree."

…Taylor said the new study showed that "downscaling" from a global analysis of the carbon-nitrogen link to system-specific scenarios indicates the relationship between the elements typically becomes even stronger. "Analyzing the problem using these methods at smaller scales could allow ecosystem management teams to better predict and influence the fate of nitrates in the environment," Taylor said....

Stream in fields between Treave and Rissick. Looking north west. Still largely cattle farming in the small hamlets around St Buryan. Camp site and pottery at Treave in the distance. Shot by Sheila Russell, Wikimedia Commons via Geograph, under the Creative CommonsAttribution-Share Alike 2.0 Generic license