While Matt Damon relied on potatoes grown from the crew’s organic waste to survive in the hit film The Martian, researchers say it may be a humble desert moss that could be crucial to the emergence of life on Mars.
Scientists in China say they have discovered Syntrichia Dog brain – a moss found in Antarctica and the Mojave Desert, among other places – is able to withstand Mars-like conditions such as drought, high radiation and extreme cold.
The team says their work is the first to look at the survival of entire plants in such an environment, with a focus also on the possibility of growing plants on the surface of the planet rather than just in greenhouses.
“The unique findings of our study lay the foundation for space colonization using naturally selected plants adapted to extreme stress conditions,” the team writes.
Prof. Stuart McDaniel, a moss expert at the University of Florida who was not involved in the study, said the idea was certainly valid.
“Growing land plants is an important part of any long-term 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 could provide other important services in space,” he said.
Dr. Agata Zupanska of the SETI Institute agreed, noting that moss could help enrich and transform rock material on the Martian surface to enable the growth of other plants.
“Otherwise, moss doesn’t taste good and isn’t a great addition to the salad,” she says.
In the journal The Innovation, Chinese researchers describe how the desert moss not only survived but also recovered quickly from almost complete dehydration. It was even able to regenerate under normal growth conditions after being stored at -80 °C for up to five years and at -196 °C for up to 30 days. It was even able to regenerate after being irradiated with gamma rays, where doses of around 500 Gy even promoted new growth.
The team then created an experimental setup that exposed the moss to pressures, temperatures, gases and UV radiation similar to those found on Mars. It turned out that the moss survived in this Mars-like environment and was able to regenerate under normal growing conditions even after seven days of exposure. The team also found that plants that were dried before such exposure performed better.
“Looking ahead, 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 space,” the researchers write.
McDaniel found that most plants cannot withstand the stresses of space travel.
“This paper is exciting because it shows that desert moss can survive short-term stresses that are likely to occur on a trip to Mars, including very high levels of radiation, very low temperatures and very low oxygen levels,” 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 the desert moss could thrive and proliferate under Martian conditions,” McDaniel said.
Zupanska added that the study did not examine, among other things, the effects of particle radiation.
“In my opinion, we are getting closer to growing plants in extraterrestrial greenhouses, and moss certainly has its place in that,” she said. “To say that moss or any other pioneer species is ready to terraform Mars or any other 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 plant growth impossible. The new study also did not use Mars-like soil.
“The mosses were treated under Martian conditions for at most a few days and then regrown on sand under Earth conditions,” he said. “Of course, that doesn’t prove at all that they can grow under Martian conditions.”
However, Prof. Edward Guinan of Villanova University in the USA described the study as impressive.
“This extremotolerant moss could be a promising pioneer plant for the colonization of Mars,” he said, but noted that the moss would need water to grow.
“We still have a long way to go,” he said. “But this humble desert moss offers the hope of making small parts of Mars habitable for humanity in the future.”
