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Nitrogen Pollution Already Changing Rocky Mountain National Park

William Bowman
University of Colorado

It’s hard to notice now, but according to a new study from the University of Colorado, the extra sprouting of a small plant high in the Rocky Mountains is the first indication that nitrogen pollution is altering the sensitive alpine region.

Plants need nitrogen to grow, but nitrogen from air pollution can have a devastating ecological impact. Bill Bowman, an ecologist and lead author of the study, wanted to figure out how much nitrogen it took to start reshaping the environment in Rocky Mountain National Park. Based on the extra growth of a particular sedge, Bowman found that current levels of pollution are already enough.

“Although these initial changes are fairly subtle, they are a portent of what may occur, and what probably will occur down the road with more serious environmental changes,” says Bowman. “Now is the time to act to control emissions before some of these detrimental effects happen.”

Eventually, the outgrowth of plants like the indicator sedge can crowd out other alpine species, reducing diversity.

Another concern is soil acidification, which allows metals like aluminum and manganese to accumulate. The metals can harm bacteria and insects in soil, and can also leach into the groundwater.

“We know based on other systems that have become acidified, that you begin to lose organisms in the streams and lakes, including fish,” says Bowman. “We’re concerned about what may eventually happen to trout in Rocky Mountain National Park.”

Bowman’s models estimate that soil acidification will occur in the Park in about two decades.

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