Park nitrogen levels growing at 2% a year
ESTES PARK ” Smoking tailpipes, fertilized fields and livestock lots seem distant from the frozen, snowy environment of Loch Vale, a lake and valley at about 10,500 feet in Rocky Mountain National Park.
But it’s here where 23 years of water-sample data have allowed researchers to determine that nitrogen levels in the park are 18 percent to 20 percent higher than they were in the preindustrial age and growing at about 2 percent annually.
This summer, the Colorado Department of Public Health and Environment will embark on the nation’s first program to reduce nitrogen pollution, which includes nitrogen oxide and ammonia.
Exactly how state health regulators will reduce nitrogen emission hasn’t yet been determined, said Mike Silverstein, manager of the planning policy program at the state Air Pollution Control Division, but the plan is to focus on working with agricultural producers to find ways to fertilize fields and raise livestock without releasing high amounts of nitrogen.
The good news, park spokeswoman Kyle Patterson said, is that permanent changes to the park’s ecology are not imminent.
“We are at the point here that we can do some things,” she said. “That is very exciting. A lot of times, you cope with it after the damage is done. Now we have the opportunity to have other agencies change some policies.”
U.S. Geological Survey ecologist Jill Baron began studying nitrogen deposition in Rocky Mountain National Park 23 years ago by setting up two sites: one’s on the park’s east side and one on its west side.
Working with park officials on the project, she is using the data to determine what ecological effects increased nitrogen is having on the park.
“What we are trying to do is look at the entire ecosystem,” Baron said.
One known outcome of high nitrogen levels is the acidification of lakes, which can kill fish and other aquatic life. When that might happen in the park if nitrogen levels aren’t reduced is unknown, but Baron has already demonstrated that algae levels in high mountain lakes are increasing along with the nitrogen.
“These are wonderful indicators of change,” she explained.
Excess nitrogen ” the gaseous element makes up 78 percent of the air we breathe ” leads to needles of pine trees taking in more water than usual, the dietary equivalent of trees wolfing down a bag of potato chips every day.
Nitrogen is “like junk food, and the needles get fat in the short growing season” under higher-than-normal levels, park biologist Karl Cordova said, and that could have several consequences.
It could mean more fuel, and that could increase fire danger. It also could reduce the number of plant species that are less responsive to nitrogen, which could change habitat and the distribution of animals dependent on those plants.
The downside, Baron said, is that water-filled needles could freeze easily and fall off during the winter, stressing the trees.
In fact, she said, studies in forests on the East Coast also have demonstrated that insects find nitrogen-rich trees more palatable, making the trees more susceptible to infestation.
Baron already has demonstrated a difference between trees on the east side of Rocky Mountain National Park and those on its west side.
In 1998, she plotted 12 sites, six on the west side of the Continental Divide and six on the east, and each at similar elevations with between 300 and 700 spruce and fir trees. Data from the sample sites showed that trees on the east side, which are exposed to upslope Front Range winds, contained more nitrogen than trees on the west side of the park.
Now, she’s adding nitrogen to the plots on the east side to see how the trees might be affected.
She expects that the additional nitrogen will result in a denser forest on that plot, with increased foliage.
Information from: Daily Times-Call, http://www.longmontfyi.com/
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