PERENNIAL ANTARCTIC LAKE ICE - AN OASIS FOR LIFE IN A POLAR DESERT

The permanent ice covers of Antarctic lakes in the McMurdo Dry Valleys develop liquid water inclusions in response to solar heating of inter nal aeolian-derived sediments. The ice sediment particles serve as nut rient (inorganic and organic)-enriched microzones for the establishmen t of a physiologically and ecologically complex microbial consortium c apable of contemporaneous photosynthesis,.nitrogen fixation, and decom position. The consortium is capable of physically and chemically estab lishing and modifying a relatively nutrient- and organic matter-enrich ed microbial ''oasis'' embedded in the lake ice cover.