Galileo spacecraft results imply that a subsurface ocean could exist on Europa. The research team tested samples from the ice 3,590 meters below Vostok Station, and found diverse colonies of microbes. Scientists say this is significant because the lake has been isolated from the usual sources of atmospheric-derived energy, such as photosynthesis, for millions of years. The lake could be an analog to sub-ice Europa or subsurface Mars where conditions are similar.
Scientists believe ice is a good environment for primitive bacteria.
The bacteria need less food because it's cold, and its metabolism slows down, somewhat like a hibernating bear's. Another finding was that DNA extracted from the microbes present in the team's Lake Vostok sample indicated the presence of only a few subgroups of known bacteria, coupled with low overall microbial diversity. The team also found signs of bacterial life in the ice core and detected metabolic activity in some of the bacteria by measuring the bacteria's respiration rates during incubation. Scientists said the sampled Vostok glacier ice also suggested that the lake water derived from a mixture of melted ice from both glacial and interglacial periods, deposited there approximately one million years ago. Although the thickness of the ice on Europa is not known, scientists think that tidal forces could form cracks extending to the surface.