Taking the pulse of Smoky Mountain streams
Why monitor the water?
To understand water quality, we have to look to the source of potential pollutants: the air. “Air and water quality monitoring are like taking the pulse of the park,” said University of Tennessee-Knoxville professor John Schwartz. “We have to have continuous monitoring,” he explained, to “answer critical management questions for natural resource protection.” One question deals with the impacts of acid contaminants (primarily sulfates and nitrates coming from air pollution) on streams and the larger ecosystem. We want to know how acidic the streams are, how fast they’re becoming acidic, and where in the park this stream acidification is the worst. In addition, Steve Moore, the Supervisory Fisheries Biologist at the Park with whom Dr. Schwartz conducts research, notes that we have lost native brook trout from six watersheds in which they used to be common. We don’t understand why the fish are disappearing in some watersheds but not others. The fish’s disappearance has driven much of the water quality research at the University of Tennessee.
Dr. Schwartz and his predecessor Dr. Bruce Robinson, along with many graduate students at the University of Tennessee, have been taking the pulse of the Smokies’ streams since 1991. They and volunteers from Trout Unlimited collect “grab samples” of water from 43 streams in different watersheds throughout the park. Every two weeks—winter and summer—they also take samples of rainwater, soil, and stream water from a long-term study site near Clingman’s Dome in the Noland Divide watershed. They chemically analyze the quality of the water, and use this basic data to ask more in-depth questions. Their analyses help us understand the patterns of pollution in the park and its impacts on the plants and animals we’re charged with protecting.
How healthy is the water?
Over many years, researchers at the University of Tennessee noticed that the water is becoming more acidic, especially at high elevations above 4000 feet. Even though our water looks clear and pristine, lab analysis reveals that it is contaminated with acidic sulfates and nitrates from air pollution.
Why does acidification matter? If you are a fish or insect larva, you prefer water that is neither acidic (like sour vinegar) nor basic (like smooth milk). You like neutral water with a pH around 7.0. Pure rainwater without any buffering minerals is slightly acidic—pH 5.6 or so—but minerals from rocks and soil capture this acidity and buffer it, so streams stay near-neutral. When rainwater is not just slightly acidic, but very—pH of 4.0 or even less—rocks and soil cannot buffer all of the acid. Much of it runs into streams, making them acidic as well. When stream water drops to pH 6.0—that’s 10 times more acidic than neutral 7.0 water—acid-sensitive fish and other creatures cannot survive. As the pH drops further, to 3.0-4.0 (as acidic as that sour vinegar), aquatic life cannot survive.
What’s the future for aquatic plants and animals?
But it's not all doom and gloom. There is hope to alter these trends by reducing air pollution so the predictions never come true. Through a combination of individual, community, and legal actions, we can change the way we live and, by doing so, improve water quality. The most recent check-up, from the 2008 Annual Water Quality Report, says that we can even be cautiously optimistic about at least some of the results:
Reversing trends through research and action
Everyone can help the Smokies’ streams by reducing acid pollution at its sources. As Dr. Schwartz said, “We need to address the problem from a public standpoint, because sulfates and nitrates are coming from air pollution. Ideally we’d put pressure on congressional representatives to clean up coal-fired power plants. The new scrubber installed at some of the East Tennessee coal-fired power plants will help, but we need more. We also need to reduce vehicle emissions as well because it is a major source of the airborne nitrates.” Vehicle emissions include exhaust from passenger cars, buses, and off-road vehicles such as boats, lawnmowers, and construction equipment.
While we’re advocating enforcement of existing laws and promoting new rules to regulate air pollutants, we can reduce our personal contributions to acid pollution.
Small things make a difference; even when you’re at home, shutting the fridge door or flipping off that light when you leave the room can help a fish high in a Smoky Mountain stream.
Researchers are constantly asking new questions and seeking their answers—you could join them by studying water quality in college and graduate school. Dr. Schwartz and his students want to find out the answers to these big questions: