KNOXVILLE, Tenn. — High elevations in the Smokies receive more acid precipitation than almost anywhere in North America, a University of Tennessee study shows.
Dr. Stephen Nodvin, a UT-Knoxville adjunct associate professor of forestry and ecology, said the precipitation contributes to nitrogen-based pollution, or nitrates, in the park which is destroying habitats for species such as the native Brook Trout.
Nodvin said acid precipitation is created when atmospheric chemicals react with emissions from coal- and oil-burning plants and automobiles. Dense forests at high elevations trap or filter these chemicals and pollutants, intensifying the problem in the Smokies, he said.
The contamination can pollute water, poison aquatic life and deplete valuable nutrients such as calcium from soil, making it less fertile, he said.
The study of about 350 park locations over five years shows some streams are nearing acid levels required by law to be posted as unsafe, Nodvin said. In some streams, acid levels jump tenfold in two days, he said.
“If this jump in acidification occurs only a few days each year, it can eliminate some aquatic plants and fish from the stream for an entire year,” Nodvin said.
The nitrates accumulate faster in streams and soils of old-growth forests such as the Smokies because old trees do not absorb it as fast as young trees, Nodvin said.
The rate of acid buildup will increase with a gypsy moth invasion expected to occur within a decade, Nodvin said. The insects eat tree foliage. Some trees — especially old ones — may not recover to absorb nitrogen from the soil.
“We expect even more nitrate contamination of many streams when the gypsy moths arrive,” Nodvin said. “The impact on stream ecosystems and water plants and animals will be high. Unfortunately, old-growth forests are the most susceptible to damage from gypsy moth infestation.”
Nodvin said Tennessee Valley Authority and Oak Ridge National Laboratory also worked on the study. Study results were published in recent issues of Water, Air and Soil Pollution and the Bulletin of the Torrey Botanical Club.
Contact: Dr.Stephen Nodvin (423-974-7126)