Nitrogen Issues

By Keith Keenan

Nitrogen Oxide (NOx) is an atmospheric pollutant caused by incomplete combustion from coal-fired industries or motor vehicles that comes back to earth in rain or snowfall. Nitrogen acts as a fertilizer, affecting high mountain lakes and streams most notably by surging the growth of algae, preventing the establishment of spawning beds. Continued exposure to NOx deposition will reach a point known as Critical Load (the point at which the surrounding plants and soils can no longer absorb the excess nitrogen). Deposition beyond Critical Load leads to acidification and death of aquatic organisms and trout habitat.

Key terms: Nitrogen Oxide, Acidification, Fertilization, Critical Load.

Ongoing Colorado Battles: In September 2004. Colorado Trout Unlimited and Environmental Defense filed a petition with the U.S. Dept. of Interior to issue a Declaration of Adverse Impact in Rocky Mountain National Park, which would require EPA to ask the State of Colorado to take measures to clean up the air over and around the Park. These guidelines were established in the Clean Air Act amendment of 1977. NOx deposition in RMNP threatens Greenback Trout habitat. Twenty years of historical research data shows that currently the level of NOx deposition in RMNP has reached Critical Load.

Additional info sources: USGS, http://co.water.usgs.gov/lochvale/res-obj.html

National Park Service, http://www.nature.nps.gov/air/pubs/RockyMT.Review/index.html

Jill S.Baron, H.M. Rueth, A.M. Wolfe, K.R. Nydick, E.J. Allstott, J.T. Minear, and B. Moraska, Ecosystem Responses to Nitrogen Deposition in the Colorado Front Range.

3 Ecosystems, 352-368 (2000).