Microbes surviving in South American volcanoes similar to Mars
Studying the most Mars-like place on Earth - the inhospitable landscape of volcanoes in the Atacama Desert of South America - scientists have found a new organism that they say could help determine what types of life may have existed on Mars.
A new DNA analysis of the rocky soil in the area revealed basic organisms called archaea, which convert energy differently than any other microbe in the world.
"We haven't formally identified or characterized the species," said Ryan Lynch, a doctoral student at University of Colorado Boulder involved in the study. "But these are 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."
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That difference may be why these organisms are able to thrive in an environment with double the ultraviolet radiation as a low-elevation desert and with temperatures that can swing from 14 degrees Fahrenheit at night to 133 degrees the next day. The slopes of volcanoes in the Atacama region, where the team collected soil samples, receive little snow and the soil is depleted of many important nutrients, including nitrogen.
While most arid mountain ecosystems are replenished by the occasional influx of ice, these volcanoes have been free of ice for the last 48,000 years, creating a biosphere of only about twenty some species that have managed to hang on for all that time, reports io9.com.
So how do the archaea do it?
The team isn't quite sure. They used fluorescent imaging to look into the cells for chlorophyll, but they couldn't find anything that suggested the microbes engage in photosynthesis. Instead, they think the archaea might slowly generate energy through chemical reactions by extracting energy and carbon from wisps of gases like carbon monoxide and dimethylsulfide that blow into the mountain area.
The Atacama microbes had to adapt to a harsh life in a desolate area, and they may have evolved differently from similar organisms because of long-term geographic isolation.
"There are a lot of areas in the world that haven't been studied from a microbial perspective, and this is one of the main ones," said team leader Steve Schmidt. "We're interested in discovering new forms of life, and describing what those organisms are doing, how they make a living."
Schmidt is working with astrobiologists to model what past conditions were like on Mars. And this finding could potentially inform a search for life on the Red Planet.
"If we know, on Earth, what the outer limits for life were, and they know what the paleoclimates on Mars were like, we may have a better idea of what could have lived there," he said.
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