Scientists detect cold-loving microbe in Nunavut’s High Arctic
Microbe shows how life could survive on solar system’s colder planets
A permafrost microbe discovered growing in Ellesmere Island at at –15 C — the coldest temperature ever reported for bacterial growth — may show how life could exist on the Saturn moon Enceladus and on Mars, where similar salty, sub-zero conditions may be found.
“What we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the solar system,” said Lyle Whyte from the Dept. of Natural Resource Sciences at McGill University in a recent news release.
Whyte and researcher Nadia Mykytczuk discovered the bacterium, called Planococcus halocryophilus OR1, after screening about 200 individual High Arctic microbes to find a micro-organism best adapted to the frigid conditions of Arctic permafrost.
They found the new microbe in permafrost core samples collected in 2004 by NASA as part of a project to develop drilling techniques that could be used on Mars.
The bacterium came from samples taken by the runway at the weather station in Eureka, in “very thin veins of very salty water.”
The salt in the permafrost veins keeps the water from freezing at the permafrost temperature of about -16 C, creating “a habitable but very harsh environment,” Whyte said.
“It’s not the easiest place to survive, but this organism is capable of remaining active (that is, breathing) to at least -25 C in permafrost.”
The microbe adapts to the extremely cold, salty conditions due to its cell structure and function, and its increased amounts of cold-adapted proteins, the scientists found.
The permafrost microbe is unusual in other ways, too: it appears to maintain high levels of compounds which act antifreeze, keeping the microbe from freezing solid, while at the same time protecting the cell from the salty environment outside.
However, these microbes may potentially play a harmful role in increasing greenhouse gas emissions.
That’s because, as permafrost melts and the number of microbes increases, they could produce more carbon dioxide emissions from melting permafrost, said Whyte told Nunatsiaq News.
This could further boost warming.
“Our team amongst numerous others around the world are studying Arctic permafrost to determine if this will be the case,” Whyte said.