The search for alien life will have to include sub-glacial oceans now that scientists at Louisiana State University have found microbes in a freshwater lake trapped in Antarctic ice, surviving on a hearty diet of melting ice, other microorganisms, and rock, raising the odds that we could find life not just somewhere in the universe but in our own solar system.

Microbes Antarctic Lake

“People weren’t really thinking about ecosystems underneath the ice. The conventional wisdom was that they don’t exist, it’s a place that’s too extreme for this kind of thing,” Louisiana State University biologist Brent Christner, reports Irene Klotz for Discovery News.

Microbes discovery raises the prospects of life on Mars

The odds that there are life basically hinges on three things, how many places there with all the necessary building blocks (eg liquid water), whether life could actually survive in those places, and the odds of life springing up when the first two requirements are met. We don’t have a good handle on that last part, but Mars has the right chemicals to support life, and knowing that we might find life deep below its surface or on one of Jupiter’s frozen moons adds a lot of excitement to some of NASA and the European Space Agency’s already planned missions. And every time we find that life can survive in some new and hostile environment on our own planet it’s a reminder that the restrictions we put on ‘habitable’ worlds are based on a pretty thin data set, all things considered.

Some argue that the comparison with Mars is overstated

While microbes certainly weren’t expected so far below Antarctica, not everyone is convinced that the results have extraterrestrial implications. NASA scientist Christopher McKay, acknowledging that the discovery is “interesting in its own right,” argues that the ecosystem Christner and his team found isn’t a good representation of the ice covered oceans we would find elsewhere in the solar system because it isn’t really a closed system. Water flows through the ice and then back out into the ocean, so even if the microorganisms themselves never leave the enclosed fresh water lake, you can’t say that they are fully isolated either. Even that minimal contact with the rest of Earth’s environment could prove to be vital to the ecosystem’s long-term survivability.