Biological and Physical Considerations of Unfrozen Water Films: Mars and Antarctic Dry Valleys

Recent work in the Antarctic has found viable microbes in the dry permafrost of University Valley, relying on only interfacial water to effect exchange with the environment. The discovery of nearly pure ice at the Phoenix landing site is a possible indicator of in situ ice segregation, a physical process that depends on the same films of unfrozen water. We have recently found that even at temperatures as low as 245K, the forces arising in these unfrozen films are sufficient to initiate lens formation. Models of the possible history of the martian high latitudes in particular, show that conditions favoring even thicker film development are likely to occur on the timescale of obliquity variations. We will review all of these recent results, and assess their potential implications for the habitability of the martian regolith.

Speaker: Aaron Zent, Planetary Science Division, NASA Ames Research Center