CORVALLIS, Ore. A team of scientists from Oregon has collected microbes from ice within a lava tube in the Cascade Mountains and found that they thrive in cold, Mars-like conditions.
The microbes tolerate temperatures near freezing and low levels of oxygen, and they can grow in the absence of organic food. Under these conditions their metabolism is driven by the oxidation of iron from olivine, a common volcanic mineral found in the rocks of the lava tube. These factors make the microbes capable of living in the subsurface of Mars and other planetary bodies, the scientists say.
The findings, supported by a grant from the National Aeronautics and Space Administration (NASA), are detailed in the journal Astrobiology.
"This microbe is from one of the most common genera of bacteria on Earth," said Amy Smith, a doctoral student at Oregon State University and one of the authors of the study. "You can find its cousins in caves, on your skin, at the bottom of the ocean and just about anywhere. What is different, in this case, is its unique qualities that allow it to grow in Mars-like conditions."
In a laboratory setting at room temperature and with normal oxygen levels, the scientists demonstrated that the microbes can consume organic material (sugar). But when the researchers removed the organic material, reduced the temperature to near-freezing, and lowered the oxygen levels, the microbes began to use the iron within olivine a common silicate material found in volcanic rocks on Earth and on Mars as its energy source.
"This reaction involving a common mineral from volcanic rocks just hasn't been documented before," said Martin Fisk, a professor in OSU's College of Earth, Ocean, and Atmospheric Sciences and an author on the study. "In volcanic rocks directly exposed to air and at warmer temperatures, the oxygen in the atmosphere oxidizes the iron before the microbes can use it. But in the lava tube, where the bacte
|Contact: Marty Fisk|
Oregon State University