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Thread: Prokaryotes 10 feet under the driest desert

  1. #1 Prokaryotes 10 feet under the driest desert 
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    A pretty amazing discovery. Where's isn't there life?

    "Two meters below the surface of the Atacama Desert there is an ‘oasis’ of microorganisms. Researchers from the Center of Astrobiology (Spain) and the Catholic University of the North in Chile have found it in hypersaline substrates thanks to SOLID, a detector for signs of life which could be used in environments similar to subsoil on Mars.
    Life is bustling under the driest desert on Earth. A Spanish-Chilean team of scientists have found bacteria and archaea (primitive microorganisms) living two meters below the hypersaline substrates in the Atacama Desert in Chile, according to the journal Astrobiology."


    Microbial Oasis Found Beneath Atacama Desert, Lessons For Mars - Space News - redOrbit


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    Forum Radioactive Isotope skeptic's Avatar
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    Fascinating stuff, LF.

    I am not sure it means much for Mars, though. We already knew that life could live in the most amazing extreme environments.

    I think there are two much more important biological questions in relation to Mars.

    1. Could abiogenesis have happened on Mars?
    2. If not, could life from elsewhere (like Earth) have travelled there, and gotten a foothold, and adapted enough to thrive under Mars conditions?

    I seriously doubt number 1., since the wet Mars stage was only probably (possibly?) a couple hundred million years.


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  4. #3  
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    Quote Originally Posted by skeptic View Post
    I seriously doubt number 1., since the wet Mars stage was only probably (possibly?) a couple hundred million years.
    Life on Earth appears to have arisen in that sort of time frame or less, so I don't see how you can exclude the possibility for Mars.
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    John

    It took Earth life more than a billion years to reach the level of complexity where it could even generate oxygen. Remember, it started with just basic chemistry - polymers inside fatty acid vesicles in water suspension - about 4 billion years ago, and the first clear cut fossil was 2.7 billion years ago. It took Earth life a long time to get to the point where it had the mechanisms to cope with extreme environments. It seems unlikely in the extreme that Mars life could start from abiotic components, and evolve to the point of living in a largely liquid-water-free environment within 200 million years.
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  6. #5  
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    skeptic

    I am in fundamental disagreement with several of your points:

    Firstly you apparently ascribe some 'higher value' to the production of oxygen. You would have to justify this non-standard view. Good luck with that.

    Even if complexity were a necessary adjunct to oxygen production that has nothing to do with the subject, which is the emergence of life. Nowhere, prior to your introduction of the issue was complexity discussed. We were simply talking about the emergence of the first life.

    That first life is generally agreed to have appeared 3.7 billion years ago. Apparently you wish to adopt another non-standard position and challenge stromatolites dated to at least 3.5 billion years ago, with isotope data strongly indicating life at 3.7 billion years ago. Again I look forward to citations justifying your aberrant position.

    Your statement about extreme environments reveals a paucity of understanding on your part. Life arose in extreme environments. Those environments were not extreme for early life. We only call them extreme because they a) differ from ours and b) it took us a long time to recognise that life could flourish in widely different environments. so, you are wrong. It did not take life long at all. In fact life seems to have started to soon after the Late Heavy Bombardment that I for one suspect pan spermia. Otherwise we have a strong suggestion that life does arise very qucikly indeed when given even a whiff of an opportunity.

    Finally, early Mars was wet. Very wet, so why do you think life their would have to evolve to live in a water free environment?

    I'm sorry if I am coming across here as aggressive skeptic, but virtually everything you have said is plain wrong, yet you've said it with such certainty you've even conned Meteor Wayne in to giving you a nice heart. I can't let such errors stand unchallenged.
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    John

    You have done a fantastic job of misunderstanding everything I said. Reading between the lines is fine, but if I say 'dog' between the lines and you read it as 'god', then we have a problem.

    First : oxygen. I did not ascribe any special higher value to producing oxygen. It was meant to simply illustrate how long it took to evolve sufficient compexity for a difficult task, and hence that it will take a long time to be sufficiently complex to withstand an extreme environment. Early life on Earth (and one assumes, on Mars) lived in a very wet environment, with everything it needed provided from abiotic processes - food offered up, 'on a plate', so to speak. To get to the point where a life form could be sufficiently sophisticated to survive in seriously difficult very cold and very dry conditions will not take a short time.

    Second ; appearance of the first life on Earth - the date. When you say 3.7 billion years, you are equally wrong with me. No-one actually knows. We simply use indicators in the fossil record, that might be quite wrong. Nor does the exact date matter in this discussion. I could discuss this further, but it is not relevent.

    Third : life arising in extreme environments on Earth. One theory is that life arose in hydrothermal vents. This is, of course, unproven. But it does not matter, since the term 'extreme' is one that is purely relative. The current ultra-cold and very, very dry environment on Mars is most definitely very, very extreme compared to a hydrothermal vent.

    Fourth : why do I think life would have to evolve to live in a largely water-free environment?
    Because the OP mentioned life on Mars as of today. Life on Mars in the early wet environment could not survive in today's cold and dry environment, so it would have to evolve quite drastically - something it has not had time to do.

    So, no. Nothing I said was wrong. What was wrong was what you interpreted, not what I said.
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  8. #7  
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    Quote Originally Posted by Lynx_Fox View Post
    A pretty amazing discovery. Where's isn't there life?
    Cool! Though I'm not that surprised since we already know other "dangerous" places where extremophiles thrive. Mars has no life? If it has the right conditions, which we know now are pretty wide and flexible, why not?
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    brody

    Mars may have life. At this point in time, we simply do not know.

    I pointed out that it is unlikely Mars went through an abiogenesis stage, since its warm and wet stage does not appear to be long enough. I could be wrong, but that is what logical deduction based on current understanding would suggest.
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    The Martian surface is clearly pretty much hostile to life as we can imagine it. What lies deep down, way past the 10 feet mark, say like around 1 mile or 5, would be interesting to know. Could well be warm and wet in places and who knows what sort of microbial communities could be down there?

    Maybe seeing the ocean as a necessary cradle of life is a bit biased? All that ocean water went somewhere and there are perhaps vast amounts of it underground, globally speaking, in liquid form to this day. If so, then the window of opportunity for life to arise is probably just as great for Mars as for Earth. Even without liquid, life could still make ends meet inside ices or even inside rocks with periodic water contact.

    I worry that we may never know if there is currently life on Mars - it may be too well hidden and inaccessible.
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    The seasonal methane releases are probably the most intriguing--whether geologic or microbes might take us some time to figure out.
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  12. #11  
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    Especially since NASA funding has basically been terminated
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