Just to get an understanding of the concern, these bats consume 2,000 to 3,000 insects per night, each, and each pair have only 1 "pup" per year.
Allen
http://www.wkyt.com/Global/story.asp?S=3691872
MAMMOTH CAVE, Ky. -- Scientists have observed increased levels of mercury
among bats in Mammoth Cave National Park, and they blame the rise in part on
pollution from coal-fired power plants.
Western Kentucky University and park experts, who conducted the research
aimed at measuring the amount of toxic metals in park wildlife, said the
endangered Indiana bat is among those with excess mercury levels.
Mercury from power plants and other sources accumulates in microscopic
plants, which are eaten by tiny animals, which are eaten by insects, which
are consumed by bats. In each stage, the amount of mercury contained in the
body grows.
Park officials said they believe mercury contamination largely comes from
emissions from coal-fired power plants, which utility companies say they are
reducing. The utilities pointed out that some mercury in the atmosphere
comes from natural sources, such as volcanoes and forest fires.
Bob Carson, the park's air resource specialist, and others involved in the
study said they have not determined whether the amount of mercury in the
bats is large enough to cause any central nervous system damage or reduced
reproduction.
That would require a better understanding among scientists of how much
mercury bats can tolerate, officials said. But the researchers said they
found mercury in bats' hair at nearly 10 parts per million, which is above
the level beyond which detrimental effects have been detected in people and
rodents.
"When I hear 10 parts per million, I would worry a bit," said David Evers,
an expert on mercury and the environment who is the executive director of
the Biodiversity Research Institute in Gorham, Maine, who is conducting bat
studies in the Northeast that are similar to the work being done at Mammoth
Cave National Park.
The study being done at the park involved teams using nets to capture
hundreds of bats over two summers, said Steve Thomas, a park ecologist.
Thomas estimated that about 6,000 to 8,000 bats inhabit the park.
Like people, the amount of mercury in bats' hair has been shown to correlate
with the amount of mercury in their bodies.
Bats are especially vulnerable to the accumulation of mercury "because their
high metabolic rate requires they consume large amounts of insects," said
Kurt Helf, a park service ecologist who worked on the bat study.
Mercury could seriously affect bats' reproduction, said Daniel Cristol,
associate professor of biology at the College of William and Mary in
Williamsburg, Va. Cristol is studying how mercury affects wildlife along the
Shenandoah River.
Environmentalists call Kentucky a "hot spot" for mercury because of its many
coal-fired power plants. And state officials have issued mercury warnings
about eating fish from waters in all 120 counties.
Mercury pollution isn't the only thing worrying park officials. The bat
study arose from concerns several years ago that proposed coal-fired power
plants in the region could hurt the park's plants and animals, including
rare or endangered mussels, cave shrimp and bats.
"We were wondering about the impact, but we had nothing to go on," Carson
said.
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