June 29, 2008
Effects of acid rain slowly lessen
Adirondack Park lakes in recovery
BY SARA FOSS Gazette Reporter
At one time, Brook Trout Lake in the Adirondacks was full of fish.
That was before the lake’s once pristine waters became too acidic for fish to live in, the
result of acid rain.
But after amendments to the federal Clean Air Act went into effect in 1990, the lake
began to recover, and several years ago the state Department of Environmental
Conversation reintroduced fish to Brook Trout Lake. Sandra Nierzwicki-Bauer, director
of the Darrin Fresh Water Institute of Rensselaer Polytechnic Institute, said she believes
it’s the first time fish have successfully returned to a lake where all of the fish died
because of acid rain.
It may be a sign of things to come.
Researchers at the Darrin Institute in Bolton Landing have been studying 30 lakes in
the southwest corner of Adirondack Park, one of the areas most severely impacted by
acid rain, since 1994. The idea, Nierzwicki-Bauer said, is to assess how these lakes have
fared since the Clean Air Act went into effect. A paper on the topic was published in a
recent edition of the scientific journal Applied and Environmental Biology, and a new
database contains information available to anyone researching acid rain.
“It’s good information,” said John Sheehan, a spokesman for the Adirondack Council.
“It’s an important move forward. We’d like to learn as much as possible.”
So far, 26 of the 30 lakes have shown a decline in acidity, although improvements
varied from lake to lake, with factors such as how deep the water is and the steepness of
the shoreline having an effect, Nierzwicki-Bauer said. Now there are several other
fishless lakes, she said, that would be good candidates for fish reintroduction.
“In general, the fact that we saw an increase in 26 of 30 lakes is pretty good,”
Other research has focused on the water chemistry of lakes impacted by acid rain.
What made the Darrin Fresh Water Institute project unique is that it looked at water
chemistry but also at “biota” — the organisms that make up the food chain in the area
being studied. Researchers studied the population of fish and aquatic plants, but also
zooplankton, the animal form of plankton, phytoplankton, the plant form of plankton, and
“In addition to looking at the chemical changes in the water, we also looked at the
biological recovery,” said Nierzwicki-Bauer, a microbiologist. “We looked at chemical
recovery, but also at life. ... We really view this as our baseline data. Before we can start
looking at what is happening and changing in the lakes, we need to know what was there
to begin with. In some lakes, we’re seeing significant changes.”
Sheehan agreed. “We’re not seeing lakes with the acid rain problem they had before,”
he said. “The ones that were marginal are now turning the corner and getting fish back.”
Prior to this study, little was known about the effects of acid rain at the bacterial level,
in part because the bacteria involved cannot be looked at under a microscope or grown in
a lab. “There was really kind of a gap,” Nierzwicki-Bauer said.
Researchers at the Darrin Fresh Water Institute collected a sample of bacteria, broke
open the cells and extracted and cloned the DNA. Some of the techniques they used,
Nierzwicki-Bauer said, are so new they did not exist just 15 years ago.
Bacteria, Nierzwicki-Bauer said, are resilient. There are thousands of different types of
bacteria, which means bacteria can thrive in almost any type of environment. What
researchers found, she said, is that some types of bacteria aren’t at all impacted by acid
rain. But other types are. The population of a species of bacteria known as
Alphaproteobacteria, for example, declines in highly-acidic water. Species of bacteria
whose population rises or falls depending on the pH — a measure of acidity — of the
water could serve as indicators of lake recovery from acidification. If water chemistry is
good, these species of bacteria should be healthy and prevalent.
Acid rain can severely decrease the diversity of plant and animal life in freshwater
lakes and ponds; the Clean Air Act, first passed in 1970, aimed to cut the industrial
emissions that cause acid rain, a chemical mixture containing nitric and sulfuric acids.
“The Clean Air Act had a positive effect,” Nierzwicki-Bauer said. “Could more be
done? Absolutely. We’re not going to declare victory.”
A study like this needs to be longterm, Nierzwicki-Bauer said.
“Even though it’s 13 years, it’s a good beginning,” she said.