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Scientists find desert moss ‘that can survive on Mars’

 
 
 
It will still need liquid-water temperature and pressure to grow, however, and only a little bit of Mars's surface can have liquid water, and only for a little bit of the time.

From the article,
The team say their work is the first to look the survival of whole plants in such an environment, while it also focuses on the potential for growing plants on the planet’s surface, rather than in greenhouses.

...
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 around 500Gy even promoting new growth.

The team then created a set-up that had similar pressures, temperatures, gases and UV radiation to Mars. It found the moss survived in this Mars-like environment, and was able to regenerate under normal growth conditions, even after seven days of exposure. The team also noted plants that were dried before such exposure faired 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 colonisation and growth in outer space,” the researchers write.
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It needs "normal growth conditions" to grow - what are the researchers calling "normal"?
Dr Wieger Wamelink of Wageningen University, also raised concerns, including that temperatures on the red planet rarely get above freezing, making outdoor plant growth impossible, while the new study did not use Mars-like soil.

“The mosses were treated under Mars circumstances for a maximum of several days and then regrown under Earth conditions on sand,” he said. “This, of course, does not show at all that they can grow under Mars conditions.”
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There is also the problem of too low atmospheric pressure in all but the lowest spots, like Hellas Planitia.

Water is not liquid for pressures below its  Triple point - pressure 611.657 Pa (6.11657 mbar), temperature 273.16 K (0.01 C).

Below that pressure, water goes directly between solid and gas, with its evaporation often called sublimation.

There is a familiar substance that does that under ordinary conditions: carbon dioxide. Its triple point has pressure 517 kPa (5.17 bar), temperature 216.55 K (-56.60 C). That's well above the Earth's sea-level atmospheric pressure: 101.3 kPa (1.013 bar).

 Atmosphere of Mars - average pressure 610 Pa (6.10 mbar)

 Hellas Planitia - it goes down 7,152 m below the topographic reference - pressure 1240 (12.4 mbar)
 
This desert moss has the potential to grow on Mars | ScienceDaily

Refers to that paper:

Tingyun Kuang, Yuanming Zhang, Daoyuan Zhang. The extremotolerant desert moss Syntrichia caninervis is a promising pioneer plant for colonizing extraterrestrial environments. The Innovation, 2024; 100657 DOI: 10.1016/j.xinn.2024.100657

It link was a bad one before today, but it now works: The extremotolerant desert moss Syntrichia caninervis is a promising pioneer plant for colonizing extraterrestrial environments: The Innovation

They tested to see how well these plants can survive by giving them Earthlike conditions. But on Mars's surface, the hostile conditions are permanent, so one will have to look for something that will grow under such conditions, rather than wait for better conditions, as this plant does.
 
It seems highly unlikely to me that any terrestrially evolved multicellular organism could survive on Mars; If we wanted to put Earth life onto the red planet, we would need to start with bacteria, ideally ones that would make conditions more Earth-like over time.

But that's all premature; Until we are 100% certain that Mars has no life of its own, it would be hugely irresponsible to introduce Earth life to that planet.

Everywhere that humans have introduced plant or animal species, we have subsequently found that there was fascinating and previously unknown life there, but sorry, it just got driven to extinction by our imports. Oops. And that's just on our own planet. So far.
 
bilby said:
It seems highly unlikely to me that any terrestrially evolved multicellular organism could survive on Mars; If we wanted to put Earth life onto the red planet, we would need to start with bacteria, ideally ones that would make conditions more Earth-like over time.

But that's all premature; Until we are 100% certain that Mars has no life of its own, it would be hugely irresponsible to introduce Earth life to that planet.

Everywhere that humans have introduced plant or animal species, we have subsequently found that there was fascinating and previously unknown life there, but sorry, it just got driven to extinction by our imports. Oops. And that's just on our own planet. So far.
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Just goes to show how ubiquitous expendable species are. 😎
 
BH said:
Could our bacteria survive subsurface there?
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Some of them may be able to, if there is liquid water and some chemical disequilibrium, some source of chemical energy.

Modern geothermal gradients on Mars and implications for subsurface liquids. - 2001

Geothermal gradients; Earth: typically 30 - 35 K/km, though  Geothermal gradient cites 25 - 30 K/km. "The effects of weather, the Sun, and season only reach a depth of roughly 10–20 m (33–66 ft)."

The deepest mines are some South African gold mines near Johannesburg:  Mponeng Gold Mine (4 km, 66 C) and  TauTona Mine (3.9 km, 55 C) and  East Rand Mine (3.585 km, 50 - 60 C) --  Johannesburg has a mean temperature of 15.5 C -- giving a gradient of around 10 K/km there.

The  Kola Superdeep Borehole has a depth of 12,262 meters with a temperature more than 180 C (7 facts about the Kola Superdeep Borehole). Nearby  Murmansk has a mean temperature of 1.1 C. That gives a gradient of 15 K/km.

The  German Continental Deep Drilling Programme (KTB) has a depth of 9,101 meters with a temperature of more than 260 C. Nearby  Munich has a mean temperature of 10.1 C. That gives a gradient of 27 K/km.

KTB's gradient was unexpectedly high compared to Kola and those South African gold mines. But Kola and the gold mines are on "cratons", blocks of old continental crust.


Back to that Mars paper.

Its authors estimate gradients of 10.6 K/km for dry parts and 6.4 K/km for icy parts.

They use concentrated brine as a reference, with a melting point of - 25 C. The best case is Mars's equator, with an average temperature of around 230 K or -43 C.

Estimated depths (brine, dry): 1.7 km, (brine, icy): 2.8 km, (water, dry) 4.1 km, (water, icy) 6.7 km.

So it's a long way down to whatever organisms might still be living on that planet.
 
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