Boreskov

OP‐40PERMAFROST ASTROBIOLOGY: TERRESTRIAL ANALOGUESOF MARTIAN ECONICHES AND INHABITANTSGilichinsky D.Soil Cryology Lab, Institute of Physicochemical and Biological Problems in Soil Sciences,Russian Academy of Sciences, Pushchino, RussiaThe terrestrial permafrost is the only wide spread and rich depository of viable ancientmicroorganisms on the Earth. From an exobiological point of view, the terrestrialpermafrost, inhabited by cold adapted microbes and protecting the microorganisms againstunfavorable conditions can be considered as a model of possible extraterrestrial cryogenicecosystems on the Earth‐like planets. Most intriguing are the traces of past or existing life onMars; these are of interest due to upcoming missions. The cells and their metabolic endproductsfound in the Earth’s permafrost provide a range of analogues that could be used asa bridge to possible Martian life forms and shallow subsurface habitats where the probabilityof finding life is highest.‘Mars‐Odyssey’ observations of neutron fluxes that found water in the subsurface layerindicated Mars as a “water‐rich planet”. Since there is a place for water, the requisitecondition for life, the analogous models are more or less realistic. If life ever existed onfrozen extraterrestrial bodies such as Mars, traces might have been preserved and could befound at depth within permafrost. The age of the terrestrial isolates corresponds to thelongevity of the frozen state of the embedding strata, with the oldest known dating back tothe late Pliocene in Siberian Arctic and late Miocene in Antarctic Dry Valleys. Permafrost onEarth and Mars differ in age: ~3‐5 million years on Earth, and ~3 billion years on Mars. Such adifference in time scale would have a significant impact on the possibility of preserving lifeon Mars. This is why the longevity of life forms preserved within terrestrial permafrost doesnot contradict the panspermia theory, but can only be an approximate model for Mars.Therefore, the main goal is to reconcile the age of permafrost on Earth and Mars byincreasing the age of terrestrial permafrost or decreasing the Martian one.1. A number of studies indicate that the Antarctic cryosphere began to develop on theEocene‐Oligocene boundary, soon after the break‐up of Gondwana and isolation of thecontinent. Permafrost degradation is only possible if mean annual ground temperature, ‐28°C now, rise above freezing, i.e., a significant warming to above 25°C is required. There isno evidence of such sharp temperature increase, which indicates that the climate and100