Mars Polar Cap- a Habitat for Elementary Life 1

• Main Authors: M. K. Wallis, J. T. Wickramasinghe, N. C. Wickramasinghe
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Key words Mars; polar habitat; ice psychrophiles; sub-crustal ice; microbial life; Antarctic; The Antarctic; Antarc*; Ice; permafrost
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.154.9274; http://www.astrobiology.cf.ac.uk/max2009_1.pdf

Ices in the Martian polar caps are potential habitats for various species of microorganisms. Salts in the ice and biological anti-freeze polymers maintain liquid in cracks in the ices far below 0ºC, possibly down to the mean 220-240 K. Sub-surface microbial life is shielded from UV radiation, but potentially activated on south-facing slopes under the midday, midsummer sun. Such life would be limited by low levels of vapour, little transport of nutrients, low light levels below a protective dirt-crust, frost accumulation at night and in shadows, and little if any active translocation of organisms. As in the Antarctic and in permafrost, movement to new habitats depends on geo-climatic changes, which for Mars’s north polar cap occur on a 50 000 yr scale, except for rare meteorite impacts. Dynamic Terrain of the North-polar cap The layering and deep ravines identified in the north polar cap (Mars Surveyor, Mars Reconnaissance Orbiter) shows this to be one of the planet’s most dynamic regions in geological terms. Four zones are distinguished in strata of the upper 800m of the cap and the upper zone shows ~30metre periodic layering which can be matched across much of the cap (MRO images, Milkovich and Head 2005). The layering is thought to record accumulation of lag deposits alternating with accumulations of