Moss species Syntrichia caninervis has the ability to survive in harsh conditions including extreme cold and radiation, making it a potential candidate for life on Mars.

A hardy moss found in desert regions around the world can survive environmental conditions deadly to nearly all other life forms, suggesting it could be the first pioneer species for the colonization of Mars.

Syntrichia caninervis Because the plant is widespread in some of the harshest regions on Earth, including Tibet and Antarctica, Li Xiaoshuang and his colleagues at the Xinjiang Institute of Ecology and Geography in Urumqi, China, decided to subject the plant to a series of demanding tests to see how well it could survive.

The researchers found that the moss could regrow after being stored at -80°C for five years or at -196°C in liquid nitrogen for a month. They also irradiated it with gamma radiation and found that radiation up to 500 gray units (Gy) stimulated the moss to regrow, while only radiation above 8000Gy caused serious damage. Most plants cannot tolerate more than 500Gy of radiation, but 50Gy is enough to cause convulsions and death in humans.

Putting all this together, the team placed the moss in a simulated Martian environment, which included an atmosphere that was 95% carbon dioxide, temperatures ranging from -60°C to 20°C, high levels of UV radiation, low air pressure, etc. After a week in the simulator, the moss was able to fully regenerate after 30 days.

One environmental factor the team didn’t address, however, is the effect of perchlorate, a toxic and corrosive chemical thought to be widespread in Martian soil.

David Eldridge Researchers from the University of New South Wales in Sydney, Australia, say that for moss to truly thrive, it will eventually need relief from the extreme cold and dryness, and on Mars, unlike Earth, those conditions are unforgiving.

“If there’s any plant that could survive on Mars, it’s moss,” he says. But Eldridge thinks that if humans brought moss to Mars and placed it on the surface, it would barely survive: “It might survive, but I doubt it would thrive,” he says.

Sharon Robinson The researcher, from the University of Wollongong in Australia, says that while the plants might survive, it’s not entirely clear why anyone would want to bring the moss to Mars. “You can’t eat it, but if it’s photosynthesizing, it might produce a little bit of oxygen,” she says. Or the moss could provide a home for tardigrades, another hardy species.