title: Extreme environments and exobiology.
abstract: Ecological research on extreme environments can be applied to exobiological problems such as the question of life on Mars.  If life forms (fossil or extant) are found on Mars, their study will help to solve fundamental questions about the nature of life on Earth.  Extreme environments that are beyond the range of adaptability of their inhabitants are defined as "absolute extreme".  Such environments can serve as terrestrial models for the last stages of life in the history of Mars, when the surface cooled down and atmosphere and water disappeared.  The cryptoendolithic microbial community in porous rocks of the Ross Desert in Antarctica and the microbial mats at the bottom of frozen Antarctic lakes are such examples.  The microbial communities of Siberian permafrost show that, in frozen but stable communities, long-term survival is possible.  In the context of terraforming Mars, selected microorganisms isolated from absolute extreme environments are considered for use in creation of a biological carbon cycle.
authors.affiliation: Department of Biological Science and Polar Desert Research Center, Florida State University, Tallahassee 32306, USA.
authors.forename: E I
authors.initials: EI
authors.lastname: Friedmann
mesh_terms: D000864:Antarctic Regions; D003081:Cold Climate; D000458:Cyanobacteria; D003889:Desert Climate; D004783:Environmental Microbiology; D018559:Exobiology; D005118:Extraterrestrial Environment; D055593:Geological Phenomena; D005844:Geology; D018535:Mars; D012800:Siberia; D018561:Space Simulation