June 9, 2012
Microbes Capable of Surviving Harsh, Mars-Like Conditions Discovered
Soil samples obtained from South American volcanoes have revealed a smattering of different microbe types that have somehow managed to survive in extreme conditions, the University of Colorado-Boulder (CU-Boulder) announced in a June 8 press release.
According to the university, the scientists behind the research discovered bacteria, fungi, and a different type of simple organism known as archaea living in conditions similar to Mars -- a landscape which they dub "some of the most inhospitable soils" on the planet.Ryan Lynch, a doctoral student at the school who was involved in the study, said that none of the species had not yet been indentified or characterized. However, he noted that the organisms, which apparently have different methods of converting energy than ordinary microbes, were "very different than anything else that has been cultured. Genetically, they're at least 5 percent different than anything else in the DNA database of 2.5 million sequences."
Lynch was part of a team led by Steve Schmidt, a professor in the CU-Boulder ecology and evolutionary biology department, which collected soil samples from some of the tallest volcanoes in the Atacama region of South America. In this area, the soil is "so depleted of nutrients that nitrogen levels in the scientists' samples were below detection limits," and ultraviolet radiation reaches levels up to "twice as intense as in a low-elevation desert."
So how do these lifeforms survive in such conditions? The researchers say that they do not yet know. According to the press release, Schmidt, Ryan, and their colleagues were unable to find evidence that the microbes harnessed the process of photosynthesis.
Instead, they believe it is possible that the microbes are capable of generating energy through chemical reactions that extract carbon and energy from gases that drift into the area -- gases such as carbon monoxide and dimethylsulfide. While this would not produce high-energy yields but could slowly accumulate enough to sustain life over a longer period of time, Lynch said.
Their findings will be published in the Journal of Geophysical Research-Biogeosciences, according to the CU-Boulder press release..
"To find a community dominated by less than 20 species is pretty amazing for a soil microbiologist," Schmidt said. "This environment is so restrictive, most of those things that are raining down are killed immediately. There's a huge environmental filter here that's keeping most of these things from growing."
"The next steps for the researchers are laboratory experiments using an incubator that can mimic the extreme temperature fluctuations to better understand how any organism can live in such an unfriendly environment," the university added. "Studying the microbes and finding out how they can live at such an extreme can help set boundaries for life on Earth“¦ and tells scientists what life can stand. There's a possibility that some of the extremophiles might utilize completely new forms of metabolism, converting energy in a novel way."