Wednesday, August 1, 2007 - 8:55 AM
S127

Life in the Wrong Places: Microorganisms in Icy Environments

John C. Priscu1, Christine A. Foreman1, James A. Raymond2, and Brent C. Christner3. (1) Land Resources & Environmental Sciences, Montana State University, 334 Leon Johnson Hall, Bozeman, MT 59717, (2) School of Life Sciences, University Of Nevada, Las Vegas, 4505 Maryland Parkway, Juanita Greer White Hall, Las Vegas, NV 89154, (3) Department of Biological Sciences, Louisiana State University, 202 Life Sciences Bldg, Baton Rouge, LA 70803

Earth’s biosphere is cold, with 14 percent being polar and 90 percent (by volume) cold ocean. More than 70 percent of Earth′s freshwater occurs as ice and a large portion of the soil ecosystem (≈20 percent) exists as permafrost. New discoveries of microbial life in cold (–5 °C) and saline lakes, permanent lake ice, glacial ice and polar snow are extending the bounds of our biosphere. The recent description of potential bacterial life in Lake Vostok, and the discovery of at least 150 other Antarctic subglacial lakes and huge subglacial rivers extend the known boundaries for life on our planet even further. Despite the spatial and temporal records for icy systems on Earth, little is know of their geobiology and many textbooks limit their definitions of the biosphere to the region between the outer portion of the geosphere and the inner portion of the atmosphere, neglecting icy habitats. Clearly, we must extend the bounds of what is currently considered the Earth´s biosphere to include icy systems. Our work on permanent lake ice and deep ice cores from the Antarctic continent has revealed that these environments provide a habitat for prokaryotic organisms and a museum for ancient DNA. Many of these organisms possess physiologies that allow them to survive in these icy habitats. We will describe the metabolic and phylogenetic diversity of these organisms and provide details on their potential to degrade hydrocarbons and release ice-binding proteins and other metabolites that appear to function as cryoprotectants.


Web Page: www.homepage.montana.edu/~lkbonney/

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