Life Found in the Deepest, Unexplored Layer of the Earth's Crust

By Andrew Moseman | November 19, 2010 4:18 pm

AtlantisMassifAt this point, after finding microorganisms that don’t mind extreme temperatures, pressure, aridity and other hardships, we shouldn’t be surprised that bacteria‘s dominion over the Earth extends to just about anywhere we look. A new expedition to the Earth’s crust has reached unprecedented depths—down to the deepest layer of the crust—and found that even there, microorganisms are tough enough to survive.

On a hypothetical journey to the centre of the Earth starting at the sea floor, you would travel through sediment, a layer of basalt, and then hit the gabbroic layer, which lies directly above the mantle. Drilling expeditions have reached this layer before, but as the basalt is difficult to pierce it happens rarely. [New Scientist]

To circumvent the Herculean task of drilling through basalt, the expedition, called the Integrated Ocean Drilling Programme, headed out to sea to find an easier drilling location.

The Integrated Ocean Drilling Program sank its drill into the Atlantis Massif (seen above) in the central Atlantic Ocean where seismic forces have pushed the deep layer, known as the gabbroic layer, to within 230 feet of the ocean floor making it easier to reach. [UPI]

The organisms living there in the deepest part of the crust were strikingly different that the populations in other rock layers, the team says in a study published in PLoS One.

One key difference was that archaea were absent in the gabbroic layer. Also, genetic analysis revealed that unlike their upstairs neighbours, many of the gabbroic bugs had evolved to feed off hydrocarbons like methane and benzene. This is similar to the bacteria found in oil reservoirs and contaminated soil, which could mean that the bacteria migrated down from shallower regions rather than evolving inside the crust, the team says. [New Scientist]

Each time we find life thriving in some bizarre and extreme locations on Earth, we’re reminded that it might be possible for organisms to survive the extreme environments of other worlds. The researchers write in their paper:

Our results raise the intriguing possibility that hydrocarbons in very deep ocean rocks support microbial communities…. Our findings, particularly regarding the presence of genes coding for methane cycling, have implications not only for Earth’s subsurface, but also for other planets such as Mars. Methane on Mars is concentrated in some equatorial regions of the atmosphere, which suggests that it is derived from localized geological sources. Although the exact mechanism by which methane forms on Mars is not known, serpentinization reactions in the Martian subsurface have recently been proposed. Therefore, similar to the Atlantis Massif, the Martian subsurface may harbor methane-consuming prokaryotes. [PLoS One]

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Image: University of Washington

CATEGORIZED UNDER: Environment, Living World
  • nick

    We will come to discover that life, as we know it, is but the barest tip of the sliver of possibilities out there. We just haven’t discovered it yet. Hundreds of billions of galaxies, hundreds of billions or trillions of stars per galaxy, multiplicitous planets around almost every star we check. At this point, I would only be shocked if we found life, in, say, an actual star – and why shouldn’t plasma be allowed to form life? We don’t have any data on whether or not it could, just our narrow slice of life exploitable to scientific study says not.

  • Oli

    Nick, stars are so hot that even molecules cannot form inside them. If life inside a star is ever found, I’ll eat my shoes.

  • cedric

    Uhm, even our own sun creates elements…its just one big hydrogen reactor that produces helium! But the molecules required to sustain life as we know it degrade at around 350C so organically based life thriving on stars is out of the question…

  • Chip Shastid

    If you look at life as a series of evolving patterns imposed on matter following statistical laws of chance and the success of these patterns in remaining organised, I find no reason why plasma based life could not exist. I do not postulate the form of the pattern ,but it seems no stranger than what we have found already.

  • scott

    Maybe all the plasma, or even the subatomic particles, (strings even), etc, is in itself…life…the whole universe could some life form, maybe not how we are conditioned or able to understand it. Laugh, whatever you like, but you dont reall know. Same with religious freaks..and even die hard athiests…both are unable to prove anything, they just have their opinions and beliefs, neither can really prove what is really going on behind the scenes.

    Anyway, I dont care if some weird archae bacteria can live on/in a vent or ice crack or pool on some moon. I am sure there are all kinds of weird things out there…but we are spending billions to find these things while so many other creatures and the ecosystem that supports them are being destroyed on our planet. I am all for spending billions to save forests and bats and weird creatures in Madagascar as opposed to finding some bug on Europa living under a mile of ice. What good is that going to do us? It seems we are so obsessed with finding life to prove we are not alone while we are allowing so much bizarre and crazy life to die around us.

  • Brian L

    I don’t laugh at all, Scott. In fact, I marvel at the universe when I consider that it functions with a “logicworks” that can scarcely be called “dead” or “nonliving.” The universe is almost sentient. It’s a quantum computer that keeps with the necessary decisions to house the existence of all cosmic existences. Why do atoms exist at the necessary mass and internal speeds to exist at all? All in the universe is essentially made of many orders of “motion,” but what motivates all motion, and all so together on so many levels? I think there’s a rational explanation for it. I think it begins by considering our definition of “life.” What in the universe says that “life” is necessarily exclusive to “organic biological life”?

    But at the same time, this article is exclusively talking about “organic biological life.” I agree that this “life” prevails upon and beneath the earth in a wide variety of forms. However, I think this only exists WITH Earth. We have not found a single microscope on Mars, and I bet all the money in the world that we won’t. Mars was somewhat similar to Earth, but that does not necessarily mean it harnessed life like Earth. Such a crude assumption is actually more fantastic than most scientists are willing to admit. The mathematical odds (by my math, of course) says that WE shouldn’t be here, yet we are here in the face of it, in PLENTY. Not only does life exist on Earth, but we even have a most thriving and deeply complex ECOSYSTEM. It’s absolutely amazing.

    I say, what if the “life” of the universe put us here, as an extrinsic instance of self-similarity to itself?

  • Iain

    Why is it that every time they discover a new extreme-ophile it heartens scientists to believe life could exist in some harsh off planet environment? The extreme-ophiles didn’t spring up in this weird place, life moved in. I’m not saying it’s impossible for life to exist elsewhere, I just don’t like the argument as put forth.

  • Lucifer

    You guys better get a grip on reality. Life in a star is nonsense, except maybe in Hollyweird.


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