From: baalke@zagami.jpl.nasa.gov   
      
   Kathleen Burton   
   NASA Ames Research Center, Moffett Field, Calif.     August 11, 2003   
   Phone: 650/604-1731 or 604-9000   
   Email: Kathleen.M.Burton@nasa.gov   
      
   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.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)