Acid Rain
Acid is a serious environmental problem, especially for lakes and forests. Its impact on northern Wisconsin lakes and forests has been studied and debated, but has never been found to be as serious as its impact in some other areas, particularly New England. Canada, and northern Europe.
Two important research studies involving northern Wisconsin are noted below. The Lowwood file on Star Lake has only one record of the pH of the lake: From a lake survey by the DNR on April 26, 1977, which recorded the pH as 7.1.
The following, extracted from the 7/28/1998 DNR Outdoor News (and reprinted both by the Lakeland Times, August 7, 1998, and the Eccola Newsletter, August, 1998) is of interest:
"Pioneering Acid Rain Program Comes to an End.
"Wisconsin's pioneering acid rain research program is winding down, possibly closing the chapter on one of the state's biggest environmental success stories and sending air pollution experts on a search for funds to continue the groundbreaking research.
"In 1985, Wisconsin became the first state to pass a law requiring utilities and other major industrial sources to reduce by half emmissions that cause acid rain. Research at that time had linked aced rain to ailing forests and lakes in Canada and Europe, and surveys in Wisconsin in the early 1980's.
"In 1986, Wisconsin started assessing utilities up to $400,000 a year for 10 years to pay for research on acid rain. When that assessment ended in 1996, utilities and the state agreed to fund some key projects for two years until the Wisconsin legislature could find a long-term funding solution.
"That interim funding ran out July 1 without a long-term solution in place, halting all but one project--a study looking at how mercury in lake water affected loon populations--and interrupting what had been up to 18-year records of how lakes and other natural resources responded to air pollutants and reductions in those pollutants....
"By 1995, utilities had decreased their overall annual sulfer dioxide emmissions by 63 percent, exceeding goals set in the acid rain law. The results of the reduction in emissions started to show: the acidity of rain declined by 75 percent, and those northern Wisconsin lakes most vulnerable to acid rain, small seepage lakes that don't have inlets or outlets, began to show signs of recovery.... [They] have seen an average increase in pH from 5.3 to 5.9, a four-fold increase [a decrease in acidity].
The Wisconsin DNR undertook a study of the acidification of a lake by using a plastic barrier to separate Little Rock Lake in Vilas County into two parts, one of which was artificially acidified. The following University of Wisconsin News Release written by Brian Mattmiller describes the project:
"UW-MADISON PROJECT SHOWS PERSISTENCE OF ACID RAIN EFFECTS
"Little Rock Lake, the site of a landmark study on the effects of acid rain, has been taken to chemical hell and back, and seemingly recovered from the trip. The University of Wisconsin-Madison study, spanning two decades, found that while the chemistry of the lake corrected itself naturally--and fairly quickly--the biological changes took much longer to bounce back. This year, the northern Wisconsin lake came full circle, returning to its natural condition after its pH levels were dramatically altered beginning in 1984. Scientists separated the hourglass-shaped lake into two basins with a mesh curtain, keeping one side in its natural state while the other was slowly acidified. From 1984 to 1990, the test basin was taken from an original pH of 6.1 down in two-year intervals to 5.6, 5.2 and 4.7. Then it was allowed to recover without intervention.It essentially became a tale of two lakes, as the character of the acidified water began to dramatically change, says Thomas Frost, director of the study and site manager of Trout Lake Station in Vilas County. Frost reported his findings this month at the annual meeting of the Ecological Society of America. 'We found that the pH levels had a controlling but indirect influence for nearly every biological factor in the lake,' says Frost. 'The nature of the food web changed completely.' Sport fish in the lake, such as bass and perch, survived the change but the offspring of fish were unable to survive. The zooplankton in the lake, a critical part of the food chain, underwent a complete revolution. Some once-rare zooplankton took over the lake, while once-dominant species almost vanished.The acidified lake became almost crystal clear in the process, and ultraviolet light penetration increased, he says. Chemical changes helped a long, filamentous algae nicknamed "elephant snot" to spread across the lake bottom.Mercury in fish increased with acidification, but study of the lake's recovery has shown that mercury deposition has declined recently. In the end, Frost says, the lake showed a remarkable resilience by returning to its pre-disturbance conditions. But the biological changes lagged behind the chemistry, taking several years longer to reach its previous balance. 'The entire ecosystem of the lake is much more resilient than individual species,' he says. "Some species were decimated and others thrived, but the sum-total of life in the lake stayed the same." The project--which took an act of the state Legislature to enable back in the early 1980s--will be a useful marker for the country as acid rain levels slowly begin to improve. In the northeast U.S., where lakes were most vulnerable to acid rain, the average pH of rainfall went from about 4.0 at its worst points in the 1980s to around 4.8 today. The improvements are in large part thanks to the Clean Air Act's capping of sulfur dioxide emissions. But that good news is tempered by the evidence from Little Rock that lakes recover slowly from biological changes driven by acidity. Frost says other studies of northeast U.S. lakes have found little improvement in pH levels. The study also demonstrated that what was intended as a single, isolated stress, acid rain, actually created other stresses on the health of the ecosystem. While the sulfuric acid caps have been an environmental success story, Frost says another major contributor to acid rain, nitric acid, is prevalent in the atmosphere and warrants further study. The study was supported by the U.S. Environmental Protection Agency and the National Science Foundation. It built on a long tradition of whole lake experiments conducted by lake researchers at UW-Madison."
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