Nitrogen polluting lakes

The chemical fingerprint of nitrogen pollution has been recorded for more than
 a century in High Lake, Southwest Alaska, and 24 other remote lakes
 in the Northern Hemisphere.

Nitrogen derived from human activities has polluted lakes throughout the Northern Hemisphere for more than a century and the fingerprint of these changes is evident even in remote lakes located thousands of miles from the nearest city, industrial area or farm.

More than three quarters of the lakes, ranging from the U.S. Rocky Mountains to northern Europe, showed a distinctive signal of nitrogen released from human activities before the start of the 20th century.

“Our study is the first large-scale synthesis to demonstrate that biologically-active nitrogen associated with human society is being transported in the atmosphere to the most remote ecosystems on the planet,” said Gordon Holtgrieve, a postdoctoral researcher at University of Washington School of Aquatic and Fishery Sciences and lead author of the report.

Burning fossil fuel and using agricultural fertilizers are two key ways humans increase the amount of nitrogen entering the atmosphere. Once in the atmosphere, this nitrogen is distributed by atmospheric currents before being deposited back on Earth in rain and snow, often thousands of miles from the source.

Double fertilizer will be used in the next 40 years to feed 3 billion more people causing more severe effects.

UW professor of aquatic and fishery sciences Schindler said that this global nitrogen pollution may interact with climate change to produce a “double whammy” that could alter remote lakes in ways not seen in the past 10,000 years.