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A future civilization on Mars could be accompanied by a very special and resilient little plant.

A kind of moss found in the desert — named Syntrichia caninervis— may be able to survive and grow in the harsh environment of Mars, according to a new journal article The innovation.

This moss can grow in freezing temperatures down to -320.8 degrees Fahrenheit and can survive levels of gamma radiation that would kill most other plants and life forms.

The plant can also withstand incredibly dry conditions, as well as a combination of dryness, intense radiation and cold weather in a simulation of conditions on the Red Planet.

“Our study shows that the environmental sustainability of S. caninervis is superior to that of some highly stress-resistant microorganisms and tardigrades,” the researchers wrote in the paper.S. caninervis is a promising pioneer candidate for colonizing extraterrestrial environments, laying the groundwork for building biologically sustainable human habitats beyond Earth.”

Mars has a number of conditions that make it challenging for potential human exploration and habitation, with a thin atmosphere composed mostly of carbon dioxide, with small amounts of nitrogen, argon, and traces of oxygen and water vapor. Atmospheric pressure on Mars is less than 1 percent of Earth’s, averaging about 6 millibars, compared to Earth’s 1,013 millibars at sea level, and the average surface temperature is about -80 degrees F, but can vary from about -195 degrees F in winter at the poles to 70 degrees F in summer at the equator.

Additionally, water on Mars exists primarily as ice, with polar ice caps composed of water and dry ice (frozen carbon dioxide). Mars also does not have a global magnetic field like Earth, meaning that everything on its surface is exposed to high levels of cosmic radiation, which would pose a significant risk to human explorers and anything grown in its soils.

This is the first time an entire plant has been tested for its ability to withstand conditions in space or on another world. Syntrichia caninervis is found worldwide and grows in harsh conditions ranging from Tibet to Antarctica, making it an ideal candidate for testing in Martian conditions.

In the paper, the researchers describe how the moss was stored at -112 degrees F for three or five years and at -320 degrees F for 15 and 30 days. After being thawed, they discovered that the plants could regenerate and grow. They also found that if the moss was dehydrated before freezing, they recovered more quickly.

They also tested the plant under different doses of radiation, finding that it survived and even thrived at levels up to 500 Gray (Gy)—humans, by comparison, typically die after exposure to about 8 Gy.

“The results show us that S. caninervis is among the most radiation-resistant organisms known,” the researchers wrote in the paper.

The researchers then combined all of these environmental factors on Mars, exposing the plant to fluctuating temperatures between -76 and 68 degrees F, low atmospheric pressure, air composed of 95 percent CO2, and high levels of ultraviolet radiation. They found that if the moss had been dried beforehand, it had a recovery rate of 100 percent 30 days after exposure, while hydrated plants also recovered, but much more slowly.

“S. caninervis represents a promising candidate as a colonizer to facilitate terra-
formative efforts of Mars or other planets. This is not just because S. caninervis
is a terrestrial plant with exceptional tolerance to multiple stresses, but also because it can
serves as a pioneer species and foundation for establishment and maintenance
of the ecosystem by contributing to oxygen production, carbon sequestration,
and soil fertility,” the researchers wrote. “Thus, S. caninervis may help drive the atmospheric, geological, and ecological processes necessary for other higher plants and animals, while facilitating the creation of new habitats conducive to long-term human settlement.”

They continued: “Although there is still a long way to go to create self-sustaining habitats on other planets, we have demonstrated the great potential of S. caninervis as a pioneer plant for growth on Mars. Looking to the future, we expect that this promising moss can be brought to Mars or the Moon to further test the possibility of plant colonization and growth in space.”

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