Scientists say they've found bacteria growing in the Canadian arctic at temperatures below freezing, nearly as cold as the surface of Mars.

Growing at just 5 degrees Fahrenheit, the coldest temperature ever reported for bacterial growth, the bacterium offers clues about some of the necessary preconditions for microbial life on other worlds, such as Saturn's moon Enceladus and Mars, where similar briny subzero conditions are thought to exist, a release from McGill University in Montreal said Wednesday.

The researchers discovered Planococcus halocryophilus OR1 after screening about 200 microbes looking for the microorganism best adapted to the harsh conditions of the arctic permafrost.

"We believe that this bacterium lives in very thin veins of very salty water found within the frozen permafrost on Ellesmere Island," McGill scientist Lyle Whyte said. "The salt in the permafrost brine veins keeps the water from freezing at the ambient permafrost temperature, creating a habitable but very harsh environment.

"It's not the easiest place to survive but this organism is capable of remaining active (i.e. breathing) to at least -25 degree C (minus 13 degrees F) in permafrost."

The bacterium adapts to the extremely cold, salty conditions in which it is found thanks to significant modifications in its cell structure and function, the researchers said.

"I'm kind of proud of this bug," Whyte said. "It comes from the Canadian High Arctic and is our cold temperature champion, but what we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the solar system."