A large and diverse family of hearty rock-eating bacteria and other microorganisms live in a freshwater lake buried a half-mile beneath Antarctic ice, new research confirms.
The finding not only adds another extreme environment where life thrives on Earth, but raises the prospect that similar species could have lived or are still living on Mars.
NASA’s ongoing Curiosity rover mission, for example, already has found that the planet most similar to Earth in the solar system once had the chemical constituents needed to support microbial life.
The new research, published in this week’s Nature, confirms initial studies 20 years ago that found microbes in refrozen water samples retrieved from Lake Vostok, the largest subglacial Antarctic lake.
Scientists at that time were not on a life-hunting expedition and the indirect sampling process later raised questions about those results.
“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 told Discovery News.
For the new study, Christner and colleagues analyzed samples directly retrieved from another subglacial lake, known as Lake Whillans, which lies beneath about a half-mile of ice on the lower portion of the Whillans Ice Stream in West Antarctica.
The lake is part of an extensive and evolving subglacial drainage network, Christner noted in the Nature paper.
Scientists discovered at least 3,931 microbial species or groups of species in the lake waters, many of which use inorganic compounds as an energy source.
With little surface melt in the area, it is unlikely that water has made its way through the half-mile of ice to reach the lake. Instead, scientists believe the water comes from geothermal heating at the base of the lake and through frictional melting during ice flows.