Life may have arisen independently on both Mars and Earth, may survive in subsurface niches on Mars, and may manifest itself via emission of gases such as methane. Microbes adapted to life in ice at low temperatures metabolize at a rate many orders of magnitude lower than their rate for exponential growth. Life in solid ice survives either until nutrients and bioelements are consumed or until alpha-particles from U and Th in the ice induce too many double-strand breaks. Our studies with scanning fluorimetry of ice cores and flow cytometry of microbes in melted ice have shown that Prochlorococcus, the dominant phototroph in the ocean, is also the dominant phototroph in Antarctic ice. Dr. Price will talk about the story of how this bacterium came to be discovered in ice and how changes in its tiny genome as a function of its depth may enable its evolution to be followed over up to a million generations.