# Is there any reason Cyanobacteria or Lichens can't survive on Mars?

According to this article "Mars atmosphere is supersaturated with water" & according to answers to this physics stack exchange question conditions do exist on the surface of Mars where fluid water can exist at certain times of the year.

Comments in this question also suggest there's more than enough carbon dioxide in the Martian atmosphere for these organisms, and unlike most plants they can supply their own oxygen needs.

While this article suggests some lichens and cyanobacteria (the organism previosly known as blue green algae) are tough enough to handle Mars.

The Hellas Planitia impact crater & Valles Marineris trench seem the obvious choices of location to try & seed these organisms (if we were going to) for their higher atmospheric pressure (both being around 7 km deep).

If I'm putting everything together properly then everything they need to survive (& even flourish, albeit in a sporadic seasonal fashion) seems to be there & given the nature of these organisms the higher radiation (on Mars compared to Earth) shouldn't be an issue, so what have I missed?

• One reason could certainly be that some of the assumptions in some of those articles turn out to be wrong. – uhoh Dec 7 '18 at 7:01
• @uhoh : true, which assumptions do you think might be most questionable? – Pelinore Dec 7 '18 at 7:05
• Since there is no actual factual data on temperature extremes, salinity, perchlorate concentration, availability of liquid water (not freezing) and simultaneously sunlight, then anything suggesting it's possible is just speculation. But I'm not saying that it's not possible. Let's see what other people more knowledgable than I have to say about it. – uhoh Dec 7 '18 at 7:26
• A supersaturated almost-vacuum is substantively different from a supersaturated atmosphere at 14.7 psi . – RonJohn May 12 at 1:50
• This is my favourite Cyanobacteria: space.stackexchange.com/questions/26954/… – Cornelisinspace Oct 4 at 19:15

We don't really know. A study from 2012 suggests that lichens and cyanobacteria could indeed survive the "obvious" perils of Mars, including radiation, low pressure, and temperatures dropping as low as $$-50°\text{C}$$.