Hopes of finding life on Mars, at least on the surface, were dealt a blow Thursday by a study revealing that salt minerals present on the Red Planet kill bacteria.
In lab tests on Earth, the compounds known as perchlorates killed cultures of the bacteria Bacillus subtilis, a basic life form, a research duo from the University of Edinburgh's School of Physics and Astronomy reported.
Perchlorates, stable at room temperature, become active at high heat. Mars is very cold.
In the new study, Jennifer Wadsworth and Charles Cockell showed the compound can also be activated by UV light, without heat, in conditions mimicking those on the martian surface.
It killed bacteria within minutes, said the team, implying the planet was "more uninhabitable than previously thought."
"If we want to find life on Mars, we have to take this into consideration and look at trying to find sub-surface life that wouldn't be exposed to these conditions," Wadsworth told AFP.
Perchlorates are natural and man-made on Earth, but are more abundant on Mars where they were first recorded by NASA's Phoenix Lander in 2008.
The fact that perchlorates killed B. subtilis in the presence of UV radiation did not necessarily mean that all other life forms would similarly die, said Wadsworth. Further tests would have to be done to confirm this.
Perchlorates have previously been spotted in lines, thought to be brine streaks, on the surface of Mars.
Their presence was presented as evidence by scientists in 2015 of liquid water on the Red Planet.
But the new study said brine seeps, "although they represent local regions of water availability, could be deleterious to cells" if they contain perchlorates.
The findings do contain some good news.
They mean that organic contaminants left on Mars by robotic exploration, of which B. subtilis is a common one, are unlikely to survive long.
It is widely accepted that the Red Planet once hosted plentiful water in liquid form, and still has water today, albeit frozen in ice underground.
Liquid water is a prerequisite for life as we know it.
Explore further:
Mars rover scientist hopes to find more evidence of liquid water
bschott
3 / 5 (4) Jul 06, 2017katesisco
3 / 5 (2) Jul 06, 2017antialias_physorg
4.3 / 5 (6) Jul 06, 2017mythreetrees
1.3 / 5 (6) Jul 06, 2017Dingbone
5 / 5 (3) Jul 06, 2017dmentgen
4 / 5 (4) Jul 06, 2017Shootist
1 / 5 (1) Jul 06, 2017cfmill3r
3.2 / 5 (5) Jul 06, 2017Tenstats
3 / 5 (2) Jul 06, 2017Uncle Al
1.4 / 5 (10) Jul 06, 2017The same feat was accomplished in Harlem, Baltimore, Camden, urban Washington, DC; Atlanta, Detroit, Chicago, Pacoima...- though it cost $10 trillion during the Obama administration.
shoshonite
1 / 5 (1) Jul 06, 2017stevden1967
5 / 5 (4) Jul 06, 2017If Earth has 100 apocalyptic events it would still be thousands of times more hospitable than Mars.
dkjack
1 / 5 (2) Jul 06, 2017snoosebaum
5 / 5 (1) Jul 06, 2017Ellray
3.7 / 5 (3) Jul 06, 2017omegatalon
5 / 5 (1) Jul 06, 2017Bongstar420
4.3 / 5 (6) Jul 06, 2017You need mircrobes that live in acide mine waste
Bart_A
1 / 5 (6) Jul 07, 2017Really, only lunatics would even give a thought that life could have existed on Mars.
Dingbone
not rated yet Jul 07, 2017Dingbone
not rated yet Jul 07, 2017PaulPaulPaulPaul
1 / 5 (2) Jul 07, 20171. Where is my air?
2. Where is my water?
3. Where is my food?
4. What will stop me from going crazy from isolation after 6 months?
antialias_physorg
5 / 5 (4) Jul 07, 2017If you have a copious energy source you can split carbon dioxide to get oxygen. In any case you should try for a closed system because the filler (nitrogen, which we can't use but is essential to prevent either oxygen or carbon dioxide poisoning) is not readily available on Mars. You want to preserve nitrogen as much as you can.
Potentially at the poles. If you have really a lot of energy at your disposal you can create it out of thin...erm..air and rock.
That one is tricky. Hydroponics might be an answer.
Same as the guys working in Antarctica. Do something you love - in this case explore and homestead on a new world - and there's little chance of going insane.
bobbysius
5 / 5 (1) Jul 07, 2017The martian surface average is more like 8 Rad/year, which can be further mitigated by choice of landing site. The radiation environment in Hellas planitia for instance is some 4 rad/year, still quite a bit more the the 0.6rad/year we get on Earth, but roughly the same as our astronauts are exposed to on the ISS. This also assumes astronauts are just hanging out on the surface without any protection. At the end of the day, radiation isn't the most serious concern in colonizing Mars.
TheGhostofOtto1923
5 / 5 (4) Jul 07, 2017torbjorn_b_g_larsson
4.3 / 5 (4) Jul 07, 2017@bscott: "This can only come as a shock to those who believe we capture all of the variables in our "simulations"."
It may come as a shock to those who believes that the purpose of simulations is to capture "all" variables instead of deepening understanding by capture system behavior. Especially if they do not see that this was a necessary experimental study (which can lead up to simulations).
@Al: "Shall we spend a $trillion to personally verify Mars is a crap hole?"
We already know that, but it is the best crap hole after Earth for a lot of things such as robotic exploration of once habitable environments. And I doubt Jennifer and Charles had access to that much money
torbjorn_b_g_larsson
5 / 5 (5) Jul 07, 2017Besides the non-sequitur, that is an erroneous claim. Not only have we seen it happen - Earth started out sterile, now it is not, so life appeared from sterile conditions - we have corroborating and yes, reproduced, evidence from bioinformatic studies of the geological conditions that resulted in emergence of life. [Weiss MC et al. 2016, The physiology and habitat of the last universal common ancestor. Nature Microbiology.; reproduced in: Williams TA et al. 2017. Integrative modeling of gene and genome evolution roots the archaeal tree of life. PNAS.]
Excitingly that geological system is known to have existed on Mars - Spirit found an example - but also in Enceladus - Cassini found that from its plumes, and can be a generic feature of small (chondrite core) *and* large (heated core) ocean moons that are not ice locked towards the core. (So not every ocean moon, unfortunately.)
Lex Talonis
1 / 5 (2) Jul 08, 2017Why not life on Marrs?
Zzzzzzzz
2.3 / 5 (3) Jul 08, 2017The addiction to fecal regurgitation is getting out of hand. Fecal regurgitators sure stink a place up.
Parsec
5 / 5 (1) Jul 08, 2017Dingbone
not rated yet Jul 08, 2017rrrander
not rated yet 21 hours ago