Hello All!   
      
   Ancient Microbes Found in Antarctic Lake        
      
   Nov. 30, 2012:  Nearly 65 feet beneath the icy surface of a remote Antarctic   
   lake, scientists from NASA, the Desert Research Institute (DRI) in Reno, Nev.,   
   the University of Illinois at Chicago, and nine other institutions, have   
   uncovered a community of bacteria existing in one of Earth's darkest, saltiest   
   and coldest habitats.    
      
   Lake Vida, the largest of several unique lakes found in the McMurdo Dry   
   Valleys, contains no oxygen, is mostly frozen and possesses the highest   
   nitrous oxide levels of any natural water body on Earth. A briny liquid, which   
   is approximately six times saltier than seawater, percolates throughout the   
   icy environment where the average temperature is minus 8 degrees Fahrenheit.   
   The international team of scientists published their findings online Nov. 26,   
   in the Proceedings of the National Academy of Sciences Early Edition.    
      
   http://science.nasa.gov/media/medialibrary/2012/11/30/splash.jpg   
      
   Scanning electron micrograph of very small and numerous bacterial cells   
   inhabiting icy brine channels in Antarctica's Lake Vida, which lies in the   
   Victoria Valley, one of the northernmost of the Antarctic dry valleys. Credit:   
   Christian H. Fritsen, Desert Research Institute    
      
   "This study provides a window into one of the most unique ecosystems on   
   Earth," said Alison Murray, a molecular microbial ecologist and polar   
   researcher at the DRI and the report's lead author. "Our knowledge of   
   geochemical and microbial processes in lightless icy environments, especially   
   at subzero temperatures, has been mostly unknown up until now. This work   
   expands our understanding of the types of life that can survive in these   
   isolated, cryoecosystems and how different strategies may be used to exist in   
   such challenging environments."    
      
   Despite the very cold, dark and isolated nature of the habitat, the report   
   finds the brine harbors a surprisingly diverse and abundant variety of   
   bacteria that survive without a current source of energy from the sun.   
   Previous studies of Lake Vida dating back to 1996 indicate the brine and its   
   inhabitants have been isolated from outside influences for more than 3,000   
   years.    
      
   "This system is probably the best analog we have for possible ecosystems in   
   the subsurface waters of Saturn's moon Enceladus and Jupiter's moon Europa,"   
   said Chris McKay, a senior scientist and co-author of the paper at NASA's Ames   
   Research Center, Moffett Field, Calif.    
      
   Murray and her co-authors and collaborators, including Peter Doran, the   
   project's principal investigator at the University of Illinois at Chicago,   
   developed stringent protocols and specialized equipment for their 2005 and   
   2010 field campaigns to sample from the lake brine while avoiding   
   contaminating the pristine ecosystem.    
      
   "The microbial ecosystem discovered at Lake Vida expands our knowledge of   
   environmental limits for life and helps define new niches of habitability,"   
   said Adrian Ponce, co-author from NASA's Jet Propulsion Laboratory, Pasadena,   
   Calif., who enumerated viable bacterial spore populations extracted from Lake   
   Vida.    
      
   To sample unique environments such as this, researchers must work under   
   secure, sterile tents on the lake's surface. The tents kept the site and   
   equipment clean as researchers drilled ice cores, collected samples of the   
   salty brine residing in the lake ice and assessed the chemical qualities of   
   the water and its potential for harboring and sustaining life.    
      
   Geochemical analyses suggest chemical reactions between the brine and the   
   underlying iron-rich sediments generate nitrous oxide and molecular hydrogen.   
   The latter, in part, may provide the energy needed to support the brine's   
   diverse microbial life.    
      
   Additional research is under way to analyze the abiotic, chemical interactions   
   between the Lake Vida brine and its sediment, in addition to investigating the   
   microbial community by using different genome sequencing approaches. The   
   results could help explain the potential for life in other salty, cryogenic   
   environments beyond Earth, such as purported subsurface aquifers on Mars.    
      
      
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
      
   More Information    
   This study was partially funded by the NASA Astrobiology Program in   
   collaboration with the University of Illinois at Chicago and the Desert   
   Research Institute, a nonprofit research campus of the Nevada System of Higher   
   Education.    
      
   For more information about DRI, visit: http://news.dri.edu/   
        
   For more information about the NASA Astrobiology Program, visit:   
   http://astrobiology.nasa.gov .     
      
      
   Regards,   
      
   Roger    
   --- timEd/386 1.10.y2k+   
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