Cold-Loving Bacteria Offer Clues for Life on Mars

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ellesmere island
Ellesmere Island, Canada, is home to cold-loving bacteria that live in permafrost. (Image credit: Joel Barker, courtesy of Ohio State University.)

A microbe discovered in the Canadian high Arctic thrives at the coldest temperature known for bacterial growth.

Researchers found the newly discovered bacterium, Planococcus halocryophilus OR1, in permafrost — permanently frozen ground — on Ellesmere Island. The organism thrives at 5 degrees Fahrenheit (minus 15 degrees Celsius), and holds clues to adaptations that might be necessary for life on Mars or Saturn's moon Enceladus, where temperatures are well below freezing.

Whyte and his team studied the bacterium's genome sequence and found that P. halocryophilus OR1 withstands the cold and salt thanks to modifications in its cell structure, cell function and an abundance of cold-adapted proteins. Changes in the cell membrane that protects the bacterium are one example of such modifications.

The bacterium also appears to contain high levels of a compound that works as molecular antifreeze, as well as protecting the cell from the salty fluid in its environment.

These microbes might be bad news for global warming, which is melting permafrost in Arctic regions. Permafrost contains dead organic matter that bacteria can break down, releasing carbon dioxide and venting the greenhouse gas to the atmosphere. More of these microbes mean more greenhouse gas gets released.

Still, Whyte calls the bacterium "our cold temperature champion," adding "what we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the solar system."

It's not the first time life has been found in permafrost conditions. Cold-loving extremophiles, called psychrophiles, are most often bacteria, fungi or algae. These hardy microbes have been found living beneath sheets of ice in Siberia and Antarctica, where temperatures range from 23 to 68 degrees F (minus 5 to 20 degrees C).

A 2006 review article in the journal EMBO Reports describes some of the adaptations organisms have developed for surviving the challenges of life at these frigid temperatures. These challenges include slowed rates of biochemical reactions and more viscous fluid environments.

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Tanya Lewis
Tanya Lewis
Staff Writer
Tanya was a staff writer for Live Science from 2013 to 2015, covering a wide array of topics, ranging from neuroscience to robotics to strange/cute animals. She received a graduate certificate in science communication from the University of California, Santa Cruz, and a bachelor of science in biomedical engineering from Brown University. She has previously written for Science News, Wired, The Santa Cruz Sentinel, the radio show Big Picture Science and other places. Tanya has lived on a tropical island, witnessed volcanic eruptions and flown in zero gravity (without losing her lunch!). To find out what her latest project is, you can visit her website.