While Matt Damon relied on potatoes grown on the crew’s biological waste to survive in the hit movie “The Martian,” researchers say it’s a simple desert moss that could be essential to creating life on Mars.
Scientists in China say they have found Syntrichia caninervis – a moss found in regions including Antarctica and the Mojave Desert – is able to withstand Martian-like conditions, including drought, high levels of radiation and extreme cold.
The team says their work is the first to look at the survival of whole plants in such an environment, while also focusing on the potential of growing plants on the planet’s surface rather than in greenhouses.
“The unique observations obtained in our study lay the foundation for the colonization of outer space using naturally selected plants adapted to extreme stress conditions,” the team wrote.
Prof Stuart McDaniel, a moss expert at the University of Florida who was not involved in the study, suggested the idea had merit.
“Cultivating terrestrial plants is an important part of any long-duration space mission because plants efficiently turn carbon dioxide and water into oxygen and carbohydrates – essentially the air and food that humans need to survive. “Desert moss is not edible, but it can provide other important services in space,” he said.
Dr Agata Zupanska, of the SETI Institute, agreed, noting that moss could help enrich and transform the rocky material found on the Martian surface to enable other plants to grow.
“Otherwise, the moss is not tasty and does not make a good addition to the salad,” she said.
Writing in the journal The Innovation, researchers in China describe how the desert moss not only survived, but rapidly recovered from almost complete dehydration. It was also able to regenerate under normal growth conditions after spending up to five years at -80C and up to 30 days at -196C, and after exposure to gamma rays, with doses of about 500Gy even inducing new growth.
The team then created a structure that had pressures, temperatures, gases and UV radiation similar to Mars. He found that the moss survived in this Martian-like environment and was able to regenerate under normal growth conditions, even after seven days of exposure. The team also noted that plants that had been dried before such exposure looked better.
“Looking to the future, we expect this promising moss to be brought to Mars or the Moon to further test the possibility of colonizing and growing plants in outer space,” the researchers wrote.
McDaniel noted that most plants cannot withstand the stresses of space travel.
“This paper is exciting because it shows that desert moss survives brief exposures to some of the stresses likely to be encountered on a trip to Mars, including very high levels of radiation, very cold temperatures and very low oxygen,” he said.
But he added that the research had limitations.
“These experiments represent an important first step, but they do not show that moss can be an important source of oxygen under Martian conditions, nor do they show that desert moss can reproduce and multiply in the Martian context,” McDaniel said.
Zupanska added that, among other problems, the study did not test the impact of particle radiation.
“In my opinion, we are getting closer to growing plants in extraterrestrial greenhouses, and moss certainly has a place in them,” she said. “To imply that moss, or some other pioneer species, is about to terraform Mars, or some other outer planet, is an exaggeration.
Dr Wieger Wamelink of Wageningen University also raised concerns, including that temperatures on the red planet rarely go above freezing, making it impossible for plants to grow in nature, while the new study did not use Mars-like soil.
“The mules were treated in Martian conditions for a maximum of a few days and then reintroduced under Earth conditions in the sand,” he said. “This, of course, does not at all indicate that they can grow in Martian conditions.”
However, Prof Edward Guinan of Villanova University in the US described the study as impressive.
“This extremotolerant moss could be a promising pioneer plant for the colonization of Mars,” he said, although he noted that the moss would need water to grow.
“We have a long way to go,” he said. “But this low desert moss offers hope for making small parts of Mars habitable for humanity in the future.”