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W.L. Davis (NASA Ames/SETI Institute), C.P. McKay (NASA Ames)
We present a quantitative assessment of the possibilities of life in an ocean in Europa, and the possibilities of dormant survival in the ice cover of Europa. We consider models of possible chemosynthetic ecologies on Europa based on extant ecosystems on Earth. In particular we consider the following analog ecosystems: 1) H2S + O2; deep sea vents 2) H2 + CO2; observed in subsurface basalt and 3) H2S + CO2 (mediated by Fe precipitation); observed in caves. We also consider combined thermal and light scattering models to determine the plausibility of photosynthetic ecologies on Europa by analogy with life within and below the ice cover of Antarctic dry valley lakes. Finally we present models of the limit of dormancy of microorganism in ice as applied to Europa. This has implications for planetary protection in upcoming missions.
The author(s) of this abstract have provided an email address for comments about the abstract: wdavis@mail.arc.nasa.gov