A newly discovered batch of microbial life has been found in a sealed brine lake located beneath 65 feet of Antarctic ice, providing scientists with a rare opportunity to examine how life may cope with extreme conditions on other planets.
A team of University of Illinois scientists have reportedly identified a diverse ecosystem in Lake Vida, an underground lake located in Antarctica. The findings, detailed in the Proceedings of the National Academy of Sciences, shed light on the extreme limits at which life can live not just on Earth, but possibly alien worlds, including Mars, say scientists.
“Lake Vida is a model of what happens when you try to freeze a lake solid, and this is the same fate that any lakes on Mars would have gone through as the planet turned colder from a watery past,” says Peter Doran of the University of Illinois, Chicago, co-author of the study. “Any Martian water bodies that did form would have gone through this Vida stage before freezing solid, entombing the evidence of the past ecosystem.”
To investigate life in the sub-Antarctic lake the team of researchers collected samples of brine from ice cores. The results showed reduced and oxidized compounds as well as high levels of molecular hydrogen. To sample the unique environment researchers worked under secure, sterile tents on the lake’s surface to keep the site and equipment clean as they drilled ice cores, collected samples of the salty brine residing in the lake ice, and then assessed the chemical qualities of the water and its potential for harboring and sustaining life.
Geochemical analyses suggest that chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine’s diverse microbial life.
“Geochemical analyses suggest that chemical reactions between the brine and the underlying sediment generate nitrous oxide and molecular hydrogen,” said Fabien Kenig, also of the University of Illinois, in the press release. “The hydrogen may provide some of the energy needed to support microbes.”
While the discovery is seem as a major breakthrough in the search for forms of extreme life, scientists warn that the discovery reveals little if any information as to whether life exists in other isolated corners on Earth, most notably Lake Vostok and Lake Ellsworth in Antarctica.
“It doesn’t give us clues about whether there’s life in Vostok or Ellsworth, but it says that under these super-salty conditions, life does OK,” says Martin Siegert of the University of Bristol, U.K., and leader of an expedition to Lake Ellsworth.
The findings could provide NASA with key information as the space agency continues its search for life. The U.S. space agency is currently in the midst of its Mars Curiosity mission, with the main goal of revealing signs that life once existed on the Red Planet. The study’s findings could provide insight as to how life may exist in extreme environments on interstellar bodies throughout the solar system, including the moons Europa, Io, and Titan.
“This study provides a window into one of the most unique ecosystems on Earth,” said Dr. Alison Murray, the report’s lead author. “Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments.”
According to Murray, additional research is needed to better understand how the microbes capture energy in order to survive the harsh conditions. The results of these studies could help explain the potential for life in other salty, cryogenic environments beyond Earth.
Funding for the Lake Vida research was supported jointly by the National Science Foundation and NASA.