Researchers find Antarctic lake water will fizz like a soda (Forwarded)

Kathleen Burton
NASA Ames Research Center, Moffett Field, Calif. August 11, 2003
Phone: 650/604-1731 or 604-9000
Email:

RELEASE: 03-57AR

RESEARCHERS FIND ANTARCTIC LAKE WATER WILL FIZZ LIKE A SODA

Water released from Lake Vostok, deep beneath the south polar ice
sheet, could gush like a popped can of soda if not contained, opening
the lake to possible contamination and posing a potential health
hazard to NASA and university researchers.

A team of scientists that recently investigated the levels of
dissolved gases in the remote Antarctic lake found the concentrations
of gas in the lake water were much higher than expected, measuring
2.65 quarts (2.5 liters) of nitrogen and oxygen per 2.2 pounds (1
kilogram) of water. According to scientists, this high ratio of
gases trapped under the ice will cause a gas-driven "fizz" when the
water is released.

"Our research suggests that U.S. and Russian teams studying the lake
should be careful when drilling because high gas concentrations could
make the water unstable and potentially dangerous," said Dr. Chris
McKay of NASA's Ames Research Center in California's Silicon Valley.
McKay is lead author of a paper on the topic published in the July
issue of the 'Geophysical Research Letters' journal.

"We need to consider the implications of the supercharged water
very carefully before we enter this lake," said Dr. Peter Doran, a
co-author and associate professor of Earth and Environmental
Sciences at the University of Illinois at Chicago.

Lake Vostok is a rich research site for astrobiologists, because it
is thought to contain microorganisms living under its thick ice
cover, an environment that may be analogous to Jupiter's moon,
Europa. Europa contains vast oceans trapped under a thick layer of
ice. Russian teams are planning to drill into Lake Vostok's 2.48 mile
(four kilometer) ice cover in the near future, and an international
plan calls for sample return in less than a decade.

An important implication of this finding is that scientists expect
oxygen levels in the lake water to be 50 times higher than the oxygen
levels in ordinary freshwater lakes on Earth. "Lake Vostok is an
extreme environment, one that is supersaturated with oxygen," noted
McKay. "No other natural lake environment on Earth has this much
oxygen."

The research also suggests that organisms living in Lake Vostok may
have had to evolve special adaptions, such as high concentrations of
protective enzymes, in order to survive the lake's oxygen-rich
environment, the researchers say. Such defense mechanisms may
also protect life in Lake Vostok from oxygen radicals, the dangerous
byproducts of oxygen breakdown that cause cell and DNA damage.
This process may be similar to that of organisms that scientists
theorize may once have lived on Europa, whose ice layer and
atmosphere are thought to contain radiation-produced radicals
and oxygen.

"We expect to find that the organisms in Lake Vostok are capable of
overcoming very high oxygen stress," said co-author Dr. John Priscu,
a geo-biologist at Montana State University in Bozeman. Priscu
heads an international group of researchers that will deploy a
remote observatory at Lake Vostok within three years and return
samples within 10 years.

The team also determined the ratios of gases in the lake. The
scientists discovered that the air-gas mixture there, besides
dissolving in the water, also is trapped in a type of structure
called a 'clathrate'. In clathrate structures, gases are enclosed in
an icy cage and look like packed snow. These structures form at the
high pressure depths of Lake Vostok and would be unstable if brought
to the surface.

Lake Vostok is located 2.48 miles (four kilometers) beneath the East
Antarctic Ice Sheet. The lake, and more than 70 other lakes deep
beneath the polar plateau, are part of a large, sub-glacial
environment that has been isolated from the atmosphere since
Antarctica became covered with ice more than 15 million years ago.
Scientists theorize that Lake Vostok probably existed before
Antarctica became ice covered, and may contain evidence of
conditions on the continent when the local climate was subtropical.

For images and further information about plans to return research
samples from Lake Vostok, go to:

http://salegos-scar.montana.edu/

The paper's authors also include K.P. Hand, Stanford University and
Dr. D.T. Andersen, the SETI Institute.

The research was jointly funded by NASA and the National Science
Foundation.