Ancient Arctic Ponds Drying Up as Climate Warms
- Ancient Arctic Ponds Drying Up as Climate Warms
US: July 4, 2007
CHICAGO - Ancient ponds in the Arctic are drying up during the polar
summer as warmer temperatures evaporate shallow bodies of water,
Canadian researchers said on Monday.
They said the evaporation of these ponds -- some of which have been
around for thousands of years -- illustrates the rapid effects of
global warming, threatening bird habitats and breeding grounds and
reducing drinking water for animals.
For the past 24 years, researchers at the University of Alberta in
Edmonton and Queen's University in Kingston, Ontario, have been
tracking ponds at Cape Herschel, located on the east coast of
Ellesmere Island in Nunavut, formerly the Northwest Territories of
Last year, when they went back to check, some of these 6,000-year-old
ponds had vanished.
"We were surprised. We arrived in early to mid-July and the ponds we
had been monitoring were dry. Some of them had dried up completely.
Some were just about to lose the last remaining centimeters of
water," said Marianne Douglas, director of the Canadian Circumpolar
Institute at the University of Alberta.
"It's really interesting to see how quickly it is happening. We could
see this trend had started a while ago but at no time did we expect
it to accelerate," said Douglas, whose work appears in the journal
Proceedings of the National Academy of Sciences.
Douglas said a study of the fossilized sediments in these pools of
water -- which are less than 6.6 feet (2 metres) deep -- showed
climate changes beginning as long as 150 years ago.
The researchers had thought these ponds were permanent. But change
has come rapidly.
"It is a bit of a tipping point. We don't know how far this warming
or drying will go," she said in a telephone interview.
Douglas, John Smol of Queen's University and colleagues took water
samples to measure the concentration of minerals and sediments in the
water. They compared it to data from the 1980s and found a
Evaporation had made the sediments much more concentrated.
They also discovered that ponds that formerly remained frozen until
mid-July were free of ice as early as late May.
"No small wonder that we are seeing evaporation occurring," she
said. "An extra month is tremendously long up there where the growing
season is so short."
The changes will have significant impact on the birds and animals
that rely on these sources of fresh water to survive and breed.
"The ecological ramifications of these changes ... will cascade
throughout the Arctic ecosystem. ... Lower water levels will have
many indirect environmental effects, such as further concentration of
pollutants," they wrote.
Story by Julie Steenhuysen