While Matt Damon relied on potatoes grown in the crew’s biological waste to survive in the hit movie The Martian, researchers say it’s a humble desert moss that could be key to establishing life on Mars.
Scientists in China say they have found Syntrichia caninervis – a moss found in areas including Antarctica and the Mojave Desert – is able to withstand Mars-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 for growing plants on the surface of the planet, rather than in greenhouses.
“The unique insights gained in our study lay the foundation for space colonization using naturally selected plants adapted to extreme stress conditions,” the team writes.
Professor Stuart McDaniel, a moss expert at the University of Florida who was not involved in the study, suggested there was merit to the idea.
“Growing land plants is an important part of any long-duration space mission because plants efficiently convert 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 could provide other important services in space,” he said.
Dr. Agata Zupanska of the SETI Institute agreed, noting that the moss could help enrich and transform the rocky material found on the surface of Mars to allow other plants to grow.
“Otherwise, moss isn’t tasty and it’s not a great addition to a salad,” she said.
In the journal The Innovation, scientists in China describe how desert moss not only survived, but quickly recovered from near-total dehydration. It was also able to regenerate under normal growth conditions after spending up to five years at -80 °C and up to 30 days at -196 °C and after exposure to gamma radiation, with doses of around 500 Gy even promoting new growth.
The team then created an assembly that had similar pressures, temperatures, gases and UV radiation to Mars. It was 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 were dried before such exposure looked better.
“Looking to the future, we expect that this promising moss could be carried to Mars or the Moon to further test the possibility of plant colonization and growth in space,” the researchers write.
McDaniel noted that most plants cannot withstand the stress of space travel.
“This paper is exciting because it shows that desert moss can survive brief exposure to some of the stresses likely to occur on a trip to Mars, including very high levels of radiation, very cold temperatures and very low oxygen levels,” he said. he said.
However, he added that the research has limitations.
“These experiments represent an important first step, but they do not show that the moss could be a significant source of oxygen under Martian conditions, nor do they show that desert moss could reproduce and proliferate in the Martian context,” McDaniel said.
Županská added that, among other problems, the study did not test the effect of particle radiation.
“In my opinion, we are getting closer to growing plants in alien greenhouses, and moss certainly has a place in them,” she said. “To suggest that moss or any other pioneer species is ready to terraform Mars or any other outer planet is an overstatement.”
Dr Wieger Wamelink of Wageningen University also raised concerns, including that temperatures on the red planet rarely exceed freezing, making outdoor plant growth impossible, while the new study did not use Mars-like soil.
“The mosses were treated under Martian conditions for a few days at most and then re-grown under Earth conditions on sand,” he said. “Of course, that doesn’t show at all that they can grow in Martian conditions.”
However, Professor Edward Guinan from Villanova University in the US called the study impressive.
“This extremely tolerant moss could be a promising pioneer plant for the colonization of Mars,” he said, although he noted that the moss needs water to grow.
“We have a long way to go,” he said. “But this low desert moss offers hope that in the future small parts of Mars will be habitable for humans.”