RAQUETTE LAKE, N.Y. - Acid-rain-caused compounds are decreasing in Adirondack lakes, lending further evidence that the region's waters are improving from decades of acid rainfall, according to new research by the state and two universities.
The study, which was recently submitted to the journal Environmental Science & Toxicology, found that in 44 of 48 lakes studied, sulfates - the building blocks of sulfuric acid - had declined since 1992. And for the first time since 1982, scientists detected a reduction in nitrates, which form nitric acid in water, in 15 of 48 lakes.
Consequently, some lakes' ability to buffer acid rain improved, said Karen Roy, program manager for the state Department of Environmental Conservation's Adirondack Lake Survey Corp. in Ray Brook. Roy and researchers from Syracuse University and the State University of New York's College of Environmental Science and Forestry conducted the analysis.
`We are excited'
"We are excited about this. We are beginning to see improvements in lake chemistry in some of our lakes," Roy told a group of 76 government officials, business leaders and educators at a conference on climate change in the Adirondacks at Great Camp Sagamore in Raquette Lake. The Adirondack Council and the Wildlife Conservation Society sponsored the conference.
The Adirondack Park encompasses some 6 million acres of public and private land in upstate New York. There are 2,800 lakes within the park.
Roy cautioned that while the results are scientifically significant, improvement in water chemistry does not necessarily mean fish and other organisms living in lakes have rebounded from acidic conditions. Roughly 500 of the lakes have already flat-lined, showing no signs of plant or animal life. Roy found no change in 32 lakes she studied, and in one lake, nitrates were going up.
"From a fish point of view, it can mean nothing for a long time," Roy said.
Left unclear in the research is why nitrates have declined, given that nitrogen oxides released into the atmosphere by power plants and cars continue to rise, despite cuts phased in during the early 1990s by the federal Clean Air Act. Sulfur dioxide, meanwhile, has declined nationwide.
One theory is that the compound's interaction with soil and plants, which absorb nitrogen from the ground and use it as a nutrient, has changed. Too much nitrogen initially was being deposited on Adirondack forests, resulting in conversion of excess by soil microbes into more acid that would run off into lakes.
This so-called saturation effect may have eased in recent years, Roy said. "There may be a reversal. There are more fluxes in nitrogen because of its relationship to the biota," Roy said, referring to the region's plant life. "Wait three years. Are we still going to be there?"
The state's research builds on other studies that have documented improvement in the lakes.
In February, researchers with Rensselaer Polytechnic Institute's Darrin Freshwater Institute found that pH, the concentration of acids in water, improved from 1994 to 2000 in 18 of 30 lakes in Hamilton and Herkimer counties.
Their research also showed gains in the diversity of microscopic plants and other wildlife.
Environmentalists at the conference said that despite the good news, deeper cuts are needed. "This shows us that we are doing a good thing," said John Sheehan, a spokesman for the Adirondack Council. "But we haven't gone far enough in recovery to mean biological recovery. Chemical recovery is only a first step."