Sightline front page, Summer 2001

SIGHTLINE

SUMMER 2001
Vol. 2 No. 1

AIR
The Acid Test

HUMAN INTERACTION
Back to the Future

WILDLIFE
Deviant Behavior

WATER
Aquatic Insects on the Frontline

INVASIONS
Big Hogs, Big Problems

VEGETATION
Managing the Land

BIODIVERSITY
Campaign to Identify Smokies' Species Continues

SIGHTLINE
is published on behalf of
Great Smoky Mountains National Park
by the
Energy, Environment and Resources Center (EERC)
at the
University of Tennessee.

EERC conducts research designed to promote real-world solutions to problems in the fields of energy, environment, technology, and economic development.

SIGHTLINE is sponsored by:

Friends of Great Smoky Mountains National Park

and

Great Smoky Mountains Natural History Association

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The Acid Test page 2

BY ELISE LeQUIRE

Back to previous page Mountains with mist

Terrestrial Effects
As acidity rises, the availability of nutrients in the soil, such as calcium and magnesium necessary for healthy tree growth, declines. High acidity also dissolves naturally occurring toxic heavy metals that, when taken up by plants, replace needed calcium and harm vegetation. In addition, the influx of nitrates from acid rain at higher elevations places vegetation in jeopardy. "Trees use nitrogen to grow, but if there's too much, it leaches out of the soil, limits calcium uptake, and increases aluminum levels," Renfro says. In fact, in Noland Divide's spruce-fir forest, soil samples show an unhealthy ratio of aluminum to calcium.

Though there have been no dramatic forest die-offs directly related to acid deposition in the Smokies like those that have occurred in the Northeast, "things don't have to die for there to be a problem," Renfro says. In fact, although the decline of the Fraser fir at Noland Divide is primarily due to an insect infestation of the balsam woody adelgid, scientists agree that acid deposition and nitrate saturation can make trees more vulnerable to stresses of all kinds, including insect pests, disease, and cold.

Aquatic Effects
Changes in stream chemistry can also directly affect aquatic life. Consider the brook trout, Salvelinus fontenalis. The brookie, also known locally as the speckled trout, is technically not a trout; rather, it is a cousin of the true trout, including brown and rainbow trout, which were introduced in the Smokies in the early 19th century after heavy logging had decimated much of the brookies' habitat. "The brook trout is our only native; therefore we are looking at policy and mandates to protect and restore it," fisheries specialist Moore says.

The brook trout evolved in naturally acidic streams typical of higher elevations, and it is the least acid-sensitive of the three trout species. But brook trout begin to approach mortality when the pH dips below 5.5, Moore says, and even a pH of 5.6 to 5.9 can stress young fish and cause reproductive problems in adults. Aluminum leached into streams is also toxic to fish.

The Park is attempting to boost existing populations of brook trout and reintroduce the fish in suitable streams. Their natural range is between 1,700 feet and 4,500 feet. "Much below 1,700 feet, you lose trout because streams are warmer," Moore says. Moreover, competition from more heat-tolerant rainbows may put pressure on the brook trout.

"We have seen a downward trend in the biomass of trout populations over 20 years, concurrent with a drop of pH," Moore says, though acid deposition may not be the sole explanation for this decline. "Confounding factors include more old-growth trees and more acidity, which is the result of an aging forest."

While sulfate deposition has gradually declined since the acid rain provisions of the 1990 Clean Air Act targeted large coal-fired power plants, streams at higher elevations are slow to recover because of their low acid-neutralizing capacity, or buffering ability. "Basically, acid-neutralizing capacity is the amount of calcium and magnesium-positive ions-that neutralize the negative ions from the acids. From an ecosystem perspective, you need more of the positive ions so the critters can thrive," Moore explains.

A number of governmental and nonprofit organizations are helping in water-quality monitoring programs. In the private sector, Trout Unlimited has helped collect water samples from about 40 of the 90 monitored sites in the Park. "A whole bunch of people are involved in measuring soil and soil-chemistry inputs and stream-chemistry outputs, trying to track all this through time," Moore says. "We don't have as much analyzed as we'd like, but we're making good progress. Despite the improvements in sulfate deposition, water quality hasn't improved."

In fact, a report by the University of Tennessee, which analyzes all of the Park's stream water samples, revealed that nine of 90 streams sampled over an eight-year period had median pH values of 5.6-the lower limit for trout viability-or less.

Room for Improvement
Since passage of the Clean Air Act of 1970 and subsequent amendments, public awareness of air pollution hazards to human health, biotic systems, and historic monuments has grown. At the same time, new technologies have produced more-economical solutions for reducing emissions from stationary and mobile sources. And considering it took several decades to create, recognize, and begin to fix the problems related to industrial, vehicular, and utility emissions, it's not surprising it may take decades to find and implement solutions.

"Thirty to 40 years out, we hope to have the right technologies implemented and to see improvements in the streams and soils," Renfro says. "Lots of preliminary computer modeling shows that the aquatic and terrestrial ecosystems will recover if pollution is lowered." Lowering emissions is therefore a top priority.

"Nitrates are still a worry, especially at the upper elevations," Renfro says. The computer models project that sulfate deposition should be reduced 70 percent and nitrate deposition by 40 percent to prevent acidification effects from increasing in Park ecosystems.

In 1998, the U.S. Environmental Protection Agency (EPA), recognizing that some regions in the Northeast and Southern Appalachian states receive a heavy burden of pollution from emission sources upwind, ruled that 22 Eastern states must significantly reduce emissions of nitrogen oxides from stationary sources. The agency allows states to design their own plans for reducing emissions. This ruling targets emissions of precursors to ground-level ozone, which is seasonal. "But enforcing stricter emissions reductions from May to September doesn't address the year-round emissions that lead to acid deposition," Renfro says.

The Clean Air Act also encourages fuel switching to reduce emissions. "The Tennessee Valley Authority (TVA) and other coal-burning utilities are shifting, to a large extent, to low-sulfur coal," says Stephen Mueller, projects manager with TVA's Energy Research and Technology Applications in Muscle Shoals, Alabama. Also, EPA has issued guidelines for refineries to reduce the sulfur in gasoline and for diesel trucks to reduce emissions that contain sulfur. "As a result, there will continue to be a movement toward lower-sulfur fuels in the near future," Mueller says.

In addition, several bills pending in Congress aim to close the grandfather clause that allows older power plants to avoid adopting newer, cleaner technologies. And the U.S. Department of the Interior has petitioned EPA to develop rules to further protect Class I areas. "We want immediate remedial action in Shenandoah, Great Smoky Mountains, and Rocky Mountain national parks," Renfro says.

Whether these efforts will be sufficient to achieve the goals of protecting Park resources is uncertain. However, Renfro says population increases, increased demand for electricity, and steady increases in regional vehicular traffic may offset projected reductions in emissions.

Natural Imperative
Acid deposition concerns multiple stakeholders. The U.S. Forest Service, for example, is concerned for the health of its forests. Park visitors expect, and deserve, to breathe clean air and hike or stroll through healthy forests. Anglers who prize the brook trout for its gaming qualities support Park efforts to safeguard aquatic ecosystems. Even the forest products industry has an interest, since nitrogen oxide is a precursor to ozone, which affects loblolly pines.

Overall, Renfro is optimistic. He believes the greatest champions for clearing the air are citizens, who can conserve energy in the home and workplace, use energy-efficient appliances and transportation, and let government officials know that air quality is important.

For more information, contact Superintendent, Great Smoky Mountains National Park, 107 Park Headquarters Road, Gatlinburg, TN 37738, 865-436-1200, or Air Resource Specialist Jim Renfro, 1314 Cherokee Orchard Road, Gatlinburg, TN 37738, 865-436-1708.