While Matt Damon relied on potatoes grown in biowaste to survive in the hit film The Martian, researchers say it’s a humble desert moss that could be crucial to establishing life on Mars.
Scientists in China say they have found Syntrichia canine fish – 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 say their work is the first to look at the survival of whole plants in such an environment, while also focusing on the potential to grow plants on the planet’s surface, rather than in greenhouses.
“The unique insights gained in our study lay the foundation for colonization of outer space using naturally selected plants adapted to extreme stress conditions,” the team writes.
Prof Stuart McDaniel, an expert on moss at the University of Florida and who was not involved in the study, suggested the idea had merit.
“Growing land plants is an important part of any long-term 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 surface of Mars to enable other plants to grow.
“Otherwise, moss is not tasty and does not make a good addition to the salad,” she said.
Write in the journal The Innovation, researchers in China describe how the desert moss not only survived, but quickly recovered from almost complete dehydration. It was also able to recover 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 promoting new growth.
The team then created a setup that had similar pressures, temperatures, gases and UV radiation to Mars. It found that the moss survived in this Martian-like environment, and could regenerate under normal growing conditions, even after seven days of exposure. The team also noted that plants that had been dried before such exposure were better.
“Looking to the future, we expect that this promising moss could be brought to Mars or the Moon to further test the possibility of plant colonization and growth in outer space,” the researchers write.
McDaniel noted that most plants cannot withstand the stresses of space travel.
“This paper is exciting because it shows that desert moss survives brief exposure 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 levels,” he said.
But he added the research has limitations.
“These experiments represent an important first step, but they do not show that the moss can be a significant source of oxygen under Martian conditions, nor do they show that the 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’re getting close to growing plants in extraterrestrial greenhouses, and moss definitely has a place in that,” she said. “To imply that moss, or any other pioneer species, is ready to terraform Mars, or any other outer planet, is an exaggeration.”
Dr Wieger Wamelink of Wageningen University also raised concerns, including that temperatures on the red planet rarely rise above freezing, making outdoor vegetation impossible, while the new study did not use Martian-like soil.
“The mosses were treated under Martian conditions for a maximum of a few days and then grown again under Earth conditions on sand,” he said. “Of course, this does not show at all that they can grow under Martian conditions.”
However, Prof Edward Guinan from Villanova University in the USA described the study as impressive.
“This extremely tolerant moss could be a promising pioneer plant for Mars colonization,” he said, although he noted that the moss needs water to grow.
“We have a long way to go,” he said. “But this humble desert moss offers hope for making small portions of Mars habitable for humanity in the future.”
