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Earth Science

Evidence of 100,000-Year-Old Life Found In Antarctic Subglacial Lake 63

Researchers taking advantage of retreating ice shelves in Antarctica have discovered evidence of life that's been sealed away for nearly 100,000 years. Lake Hodgson on the Antarctic Peninsula, once covered by over 400 meters of ice, is now obscured only by a thin layer three to four meters thick. Scientists carefully drilled through the ice and took samples (abstract) from the layers of mud at the bottom (as much as 93 meters below the lake's surface). "The top few centimetres of the core contained current and recent organisms which inhabit the lake but once the core reached 3.2 m deep the microbes found most likely date back nearly 100,000 years. ... Some of the life discovered was in the form of Fossil DNA showing that many different types of bacteria live there, including a range of extremophiles which are species adapted to the most extreme environments. These use a variety of chemical methods to sustain life both with and without oxygen. One DNA sequence was related to the most ancient organisms known on Earth and parts of the DNA in twenty three percent has not been previously described."
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Evidence of 100,000-Year-Old Life Found In Antarctic Subglacial Lake

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  • by ackthpt ( 218170 ) on Tuesday September 10, 2013 @06:23PM (#44813793) Homepage Journal

    and like avian bird flu can take down humans, as well.

  • "Are my global warming carbon credits still accepted in this millennium?"
    • "Yes, but we're trying to warm the planet now to prevent an ice age. Those are now considered debt."

      • "Also I'm one of the aliens who has populated the planet in your absence. Hi! Wow we're really similar except for the foreheads."

  • To aliens from another planet, we humans might appear to be extremophiles. At least we'd be worthy of study. There's that.
    • Re:Reprieved ! (Score:5, Interesting)

      by Samantha Wright ( 1324923 ) on Tuesday September 10, 2013 @10:44PM (#44815691) Homepage Journal
      Not likely! While I don't really want to go through the exact details of it (I've had hilariously long and protracted conversations about this before), liquid water and the chemistry of the common non-metals (hydrogen, oxygen, nitrogen, and carbon) at temperatures where water is liquid have some fairly special properties that make them really well-suited to giving rise to life. Ammonia instead of water seems possible, but a few sci-fi staples like silicon-based lifeforms are extremely unlikely—and given the fickleness of what we know about abiogenesis, it's likely that any emergent life that starts off using anything unfamiliar will optimize toward something more similar to what we have. Strange things might be possible, but it's pretty likely alien life will be... compostable (if not edible) by us Earthlings.
      • by homsar ( 2461440 )
        What about Earth-like life of opposite chirality? As far as I know there's no advantage to our chirality, it's just a spontaneous symmetry-breaking style effect, so it seems plausible that another planet might have identical-seeming biochemistry but be of the opposite chirality.
        • Re:Reprieved ! (Score:5, Interesting)

          by Samantha Wright ( 1324923 ) on Wednesday September 11, 2013 @02:58AM (#44816805) Homepage Journal

          Yeah, that's the biggest difference between "compostable" and "edible." There are a lot of detritovores that don't care about the chemicals they're chewing up; unless it's something toxic enough to kill them, anything just looks like a carbon chain in dire need of stripping. Molecules of the wrong chirality definitely fit in this category.

          That being said, chirality isn't the only thing that you can count on being totally arbitrary. The choice of amino acids is pretty fickle (humans only have 20, some species have two more, and we often modify them... and there is a more-or-less infinite number of them that nothing on Earth uses at all. [wikipedia.org]) Nucleotides are similar [wikipedia.org], and the debate about nucleic acid backbones is open [wikipedia.org]. There are countless opportunities for different preferences amongst sugars (we're designed around glucose, rather arbitrarily) and other metabolites. In a real-life validation of all of this, Archaeans don't even use normal phospholipids in their membranes [wikipedia.org]! (Which seems like such a bizarrely difficult thing to do that I sometimes wonder if it isn't evidence of multiple abiogenesis events, but that's a bit flimsy.)

      • by delt0r ( 999393 )
        Something also left out is nucleosynthesis. Basically where does anything heaver than lithium come from. We have a pretty good idea on these processes. The upshot is that if you have silicon you are going to have carbon and other easier materials to deal with. Bottom line is that carbon is just really awesome and forming lots of different stable compounds and polymers and water is an amazing solvent.

        Also we tend to forget that life as we know it already uses most of the periodic table.
        • Exactly; if, for some reason, some form of pre-life began using weird components like a nitrogen-phosphorus backbone or a silane backbone, it's almost certain there would be more Earth-like replacements more readily available—and there are already whole frickin' nebular clouds of bits and pieces of organic molecules, so it's not like the universe is really lacking in opportunities for this sort of thing anyway. Some arguments have been made about silicon perhaps being more viable at extreme temperatur
  • It never [imdb.com] ends [imdb.com] well [wikipedia.org].
  • I am a biologist and I don't know what "fossil DNA" is.

  • So that's where they buried Dick Clark.

  • by Anonymous Coward

    How did this article pass peer-review? What is "the most ancient organisms known". The article doesn't cite anything for this. I'm a molecular ecologist, and have never head of such thing. Another thing, it seems like they didn't have a clue of how to analyze 16S amplicons. Yes, 23% of their reads couldn't be assigned into a genus. So what? That's a very normal outcome. Why didn't they cluster these into OTUs and see where the OTUs go in the 16S tree? There are super easy-to-use pipelines for this. Yeah. In

  • I, for one, welcome our new Reaper overlords!

God doesn't play dice. -- Albert Einstein