I'm interested in the introduction of bacteria on Mars. If a small base were set up with attempts to maintain some sort of sterilisation protocols, but all the humans died on that base a) what would happen to the bodies and b) what would happen to the bacteria contained within the bodies themselves?

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    $\begingroup$ Welcome to the site Hmars, please take the tour and read up in our help centre about how we work: How to Ask We need more information in order to answer effectivley. Are all these bodies inside the sealed base with automatic atmosphere processing and temperature control or is it exposed to martian atmosphere and day/night cycle temperatures. You can edit your question to clarify. $\endgroup$ – Tantalus' touch. Feb 14 '19 at 10:42
  • $\begingroup$ 'b) what would happen to the bacteria contained within the bodies themselves?' Whatever the author wants to speculate. I am afraid there is no precedent for being able to make any particular determination any more valid than any other. Not until it actually happens will we know what happens. $\endgroup$ – Justin Thyme Feb 14 '19 at 14:35
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    $\begingroup$ It's not the only possible answer but The Martian dealt with this issue to a degree. Most things are immediately freeze-dried when exposed to Martian atmosphere. It may be useful in researching your query, since Andy Weir's research is pretty solid. (Note: I mean the book, not the movie.) $\endgroup$ – Cyn says make Monica whole Feb 14 '19 at 16:15
  • $\begingroup$ This sounds like a science based question but without the science based tag. So what would happen? whatever you want to happen. Are you asking for suggestions on how bacteria will survive? $\endgroup$ – Trevor Feb 14 '19 at 18:36
  • $\begingroup$ @CynsaysmakeMonicawhole Though Weir himself has admitted to taking some liberties for the sake of the story. (Most notably the catastrophic dust storm that starts the whole thing - while Martian winds may be faster than those on Earth, the atmosphere is so thin there's no way it would be strong enough to knock stuff over as depicted in the story.) It's a very good book scientifically speaking, but not 100% accurate in some cases. $\endgroup$ – Darrel Hoffman Mar 11 '20 at 16:22

Mars is a very dry place, so the bodies would quickly desiccate. (About the only way this could be escaped is if the bodies just happened to be positioned partway down the equator-facing wall of a crater which happens to intersect water-bearing strata just as they produce some of their rare seepage... In other words, not very easily.)

The desiccation would stop all microbial life and the body would effectively mummify as bodies have mummified in desert areas on Earth when undisturbed by animals -- remember that Mars is nearly everywhere drier than Terrestrial deserts. Desiccation would be very quick: days, not months.

What would happen afterwards? First, some bacteria respond to desiccation by going onto a spore stage. I don't know if any of those are the bacteria commonly found in tissue, though it seems unlikely since tissue-resident bacteria would not need that adaptation very often. But maybe some do.

If the mummy later encountered water -- a rare surface flow or water from a future terraforming project -- some bacteria might re-activate and go on about their lives, munching away on the organics until either the organics or the water ran out. Then they'd go back to being spores with little chance of a second revival.

The countervailing effect is that the Martian surface is dangerous to life in other ways than simple dryness. Highly oxidizing compounds such as perchlorates are common in the Martian soil and these would oxidize the mummy's organics. (I can't estimate how quickly, but probably more quickly than air oxidizes mummies on Earth.) They'd also instantly kill any bacteria or bacterial spores they encountered.

Additionally, UV radiation is strong, and this also would tend to destroy organics on the surface.

Probably the best chance of long-term survival would be if the body was covered by a dune which would shield it from the UV and leave it in unchanging soil so that once the nearby perchlorates (etc.) were used up, what was left would probably remain for quite a while.

But even bacterial spores are not eternal -- DNA degrades from random molecular motion and quantum mechanical effects -- so that there is some limit after which even the most carefully preserved spores would not revive.

The sterilization protocols strike me as more of self-sustaining a bureaucracy than as a needed precaution. (Especially since rocks from Earth probably are thrown to Mars fairly frequently.)

  • $\begingroup$ Citation for "rocks from Earth probably are thrown to Mars fairly frequently"? $\endgroup$ – Dalila Feb 15 '19 at 22:13

Bacteria will stay alive as long as it receives resources. Like any other organism, bacteria also needs oxygen, water, and resources to produce amino acids. These are necessities. So after using all the resources of the dead body, the bacteria will die.

If you are asking if bacteria can evolve and survive, that would be a topic of research and sci-fi.

  • $\begingroup$ No, many bacteria do not die when resources end: en.wikipedia.org/wiki/Endospore $\endgroup$ – Mołot Feb 14 '19 at 11:16
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    $\begingroup$ well still it doesn't change the fact that there is not future for them without external interference $\endgroup$ – Harsh ramani Feb 14 '19 at 11:24
  • $\begingroup$ Some bacteria are even happy in the vacuum of space. $\endgroup$ – Trevor Feb 14 '19 at 18:30
  • $\begingroup$ There are theoretically still living microbes on-board the Voyager probes. Not because they were placed there deliberately, just because it's impossible to 100% sterilize anything. Right now, they'd qualify as the most distant living organisms in the universe that we know of. $\endgroup$ – Darrel Hoffman Mar 11 '20 at 16:25

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