There's Life Inside Earth's Crust
noemamag.com

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131 points

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jprohov

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8 months ago

48 comments

southernplaces7 ・ 8 months ago

A fascinating thing about complex life in the deep crust lies how said life allows the earth to regenerate ecosystems even under the most extreme hypothetical conditions, and has probably done so in the past:

For example, if a super-asteroid the size of a minor planet were to hit the Earth, it's believed that it would essentially boil away all the oceans and cook the whole of the planet's atmosphere. Studies have also shown that it would likely super-heat the crust down to a depth of hundreds of meters, even in parts far from the immense and totally liquefied impact site itself.

But, in those more distant parts of the crust, far down in the dark beyond the reach of post-impact heating, below a depth of several hundred meters, microbes of all kinds would continue to live, hidden in so many tiny, watery cracks. As thousands of years pass after such a colossal impact, as the atmosphere reforms, as the earth's water re-condenses, and falls back to the surface in gigantic ocean-filling torrential rain storms, those hidden microbes, which had found their refuge in the deep rocks, would eventually creep upwards.

They'd slowly find their way back into these reformed oceans, lakes and rivers, back into the again cooled atmosphere, back into the sunlight, and the evolutionary process would kick into gear all over again.

It's speculated that our planet has survived at as many as several completely surface destroying impacts by minor planets or asteroids several hundred kilometers across, impacts that make the dinosaur impactor seem like a children's party firecracker in comparison, and this is how life regenerated from these cataclysms.

mohn ・ 8 months ago

This reminded me of a Kurzgesagt video from a few months ago on the same topic [0]. I see that the author, Karen Lloyd, was one of the experts they consulted when making that video.

[0] https://www.youtube.com/watch?v=VD6xJq8NguY

UncleSlacky ・ 8 months ago

Reminds me of Thomas Gold's "Deep Hot Biosphere" theory: https://en.wikipedia.org/wiki/Thomas_Gold#%22Deep_Hot_Biosph...

  • tim333 ・ 8 months ago

    I got sucked into spending quite a while reading about that stuff after seeing a link to Gold on HN. He was an interesting guy. Since he died in 2004 some of his ideas, like a lot of life in the crust seem to have proven correct. Others - that most oil and gas has a primordial origin, not from life seem mostly wrong. There are definitely primordial hydrocarbons - Titan has seas of methane. However on the inner planets a lot evaporated and the majority of our fossil fuels seem of biological origin.

    There's a maybe better (very good) article on life in the crust from the NYT june 2024 here https://www.nytimes.com/2024/06/24/magazine/earth-geomicrobi... . Top comment "This article is one of the most powerful articles I have ever read in the NYT. I am so grateful that the author wrote it. It cemented my belief that that all life is deeply connected from the beginning to the present day and beyond..."

mmooss ・ 8 months ago

> The major categories of visible life on Earth have been pretty much settled for centuries. But it wasn’t until the 1980s that scientists found “intraterrestrials” — microscopic organisms living in what the biogeochemist David Valentine calls a “microbial purgatory deep below the Earth’s surface."

Does anyone know the paper(s) from the 1980s where the discovery was published?

  • wiml ・ 8 months ago

    Here's a survey article from the late 80s which should have a rich references section for you:

    Ghiorse & Wilson, https://doi.org/10.1016/S0065-2164(08)70206-5

    I think there are two strands: petroleum companies have long been interested in any connection between deep biology and oil; and I think around that time people found microbes in a few sterile-seeming aquifers.

    • mmooss ・ 8 months ago

      Thanks!

BurningFrog ・ 8 months ago

If there is life on Mars, it will be deep underground!

Do we know anything about the occasional Methane emissions I heard about on Mars?

  • api ・ 8 months ago

    There are areas on Mars where we strongly believe brine is right below the surface, so there could be life underground but it may not all be that deep.

    Edit: found it:

    https://www.jpl.nasa.gov/images/pia10911-ice-on-mars-now-its...

    There have been cases where we believe we've seen ice form in rover tracks, hinting at water just below the surface.

    • sheepscreek ・ 8 months ago

      This is incredibly exciting! I had no idea that we have photo evidence of ice on Mars. Thank you for sharing this!

      Update: It’s so hard to believe that this was captured in 2008!

      • njarboe ・ 8 months ago
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        Liquid water below the surface is the newer interesting part. You can see Mars ice caps with a telescope from Earth.

        • somenameforme ・ 8 months ago
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          I think this also derives naturally from another really interesting observation. The surface of Mars, that apparent desert, is 2%+ water by weight. [1] I say "+" because later studies have shown it to be even moister. So this is really interesting in the context of the movie/book "The Martian" because this surprise came out after the book was released.

          A huge part of the plot is about him getting water which he ultimately does by extracting it from fuel, but it'd have been trivial to get it from the soil itself. If you can excuse the butchery of measurements, even just the 2% level is moist enough to extract a liter of water per cubic foot of soil! For more consistent measurements, that's 35 liters of water per cubic meter of soil!

          I suspect when we finally get boots on the ground and can start doing real research and exploration, we're going to find more surprises than we could ever imagine.

          [1] - https://www.space.com/22949-mars-water-discovery-curiosity-r...

          • api ・ 8 months ago

            We may have to decontaminate the water, which might be full of azides or other things. On the flip side those compounds may be useful for industry or fertilizer in the long term.

NBJack ・ 8 months ago

Perhaps. If it does, it probably couldn't be past a certain depth. The deepest man-made hole was about 12km, and reached roughly 180C at that depth. That's well beyond what even the most durable hyperthermophile organisms can withstand, to speak nothing of what the pressure would be like at greater depths.

  • lolinder ・ 8 months ago

    Every time we assume a limitation like this we've been wrong. If tardigrades can survive floating through space, I think it's reasonable to guess that there might be life that survives at the other extreme.

    • throwup238 ・ 8 months ago

      Where do you draw the line for the other "extreme"?

      Assuming carbon based life as we know it, 300-400C is the probably a hard limit at which point single carbon bonds begin to break down.

      Assuming life on earth as we know it, with ATP universally conserved across the entire evolutionary tree, the limit is really 150C. We've seen incredible survival adaptations like cryptobiosis but no organism exists that doesn't use ATP as its most basic unit of energy storage. That's the theoretical limit, but realistically other highly conserved critical pathways start to break down well before that temperature.

      • kergonath ・ 8 months ago
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        > Assuming carbon based life as we know it, 300-400C is the probably a hard limit at which point single carbon bonds begin to break down.

        Carbon-Carbon covalent bonds are the strongest we know. 300°C is nothing, carbon melts beyond 3000°C. Some organic molecules in our cells degrade at higher temperatures, but it depends on the availability of other species to react. Otherwise, hydrocarbon chemistry can be done beyond 300°C.

        I am not saying that this kind of organisms are likely (I have no clue, it’s not my field). But from a chemical point of view there are 2 factors that could be at play:

        - exotic organisms could rely on different chemistries altogether to produce energy and rely on molecules that are unstable under our standard conditions;

        - and also chemistry under pressure could be very different from what we are used to on the surface.

        • throwup238 ・ 8 months ago

          I don’t know why you think carbon’s melting point or hydrocarbons are relevant to basic biochemistry. The “strongest” bond we know of breaks down starting at 300C (~500C for double iirc). It’s not bulk graphite or under extreme pressure underground.

          You can fantasize about exotic biochemistries all you want, but what we know about carbon based life here on earth is rather specific in its limits.

      • CuriouslyC ・ 8 months ago

        I don't see why there could't be stabilizing adaptations for phosphate groups, or evolution of alternatives like phosphonates, thiophosphate or imidophosphate. Evolving stable enzymes that still have catalytic activity is also a big lift, but life consistently surprises us.

    • alpaca128 ・ 8 months ago

      While it’s true and impressive that tardigrades can survive all that, that doesn’t mean they can thrive there. They survive it by entering a stasis, but that’s about as far from living as one can get temporarily.

  • tim333 ・ 8 months ago

    There's loads of life down there but there seems a top limit to all known life around 130C. "The current record growth temperature is 122 °C, for Methanopyrus kandleri".That allows you to go ~10km down.

  • NoTeslaThrow ・ 8 months ago

    Seems a lot more productive and straightforward to sample rather than speculate.

    • smartaz42 ・ 8 months ago

      Hmm, but speculation is so easy and sampling is anything but. Some of Einstein's speculations were pretty damn productive. The later experiments aka samplings (Einstein proved right again!) were in my view not particularly productive.

donkeyboy ・ 8 months ago

From what i read, this post doesnt announce we’ve found some crazy extremophile unicellular microbe. Just that there is evidence to suggest they are there (due to the chemical makeup of soil/boreholes).

  • LoganDark ・ 8 months ago

    1 cross borehole electromagnetic imaging rhubarb

LorenDB ・ 8 months ago

I mean, there are earthworms in my backyard, so we've technically known that life exists in the crust for approximately forever.

didgetmaster ・ 8 months ago

>If the subsurface were like an inert container, we could just pump that gas down there, sit back and watch the global temperature stabilize and the glaciers creep back to where they’re supposed to be.

I find it fascinating how some scientists seem so sure about how things are 'supposed to be'. The Earth's climate has never been static. Almost everything present today (temperature, pressure, percentage of each gas in air, etc.) has been higher and lower (sometimes by a lot) in the past.

What makes anyone think that they know the ideal amount of anything? Higher temperatures will certainly cause change, but why does every prediction paint a 'worst case scenario'?

  • culi ・ 8 months ago

    We can pretty clearly delineate how much of warming and CO2 concentration is human-caused.

    That's clearly what they mean by "how its supposed to be". Yes there's no true "how it's supposed to be" but there's no use in being pedantic when we all clearly understand what they're talking about.

    • card_zero ・ 8 months ago

      I think you're hesitating over saying "it's supposed to be nice for people".

      But that is what most of us tacitly suppose. Ultimately the world's a park.

      • culi ・ 8 months ago
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        That's not what I'm saying at all. The typical approach is to compare co2 concentration and/or temperatures to pre-industrial levels

        • card_zero ・ 8 months ago
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          Why not say it, though? There's only us here capable of doing any supposing. Why would we say "it's supposed to be nice for cyanobacteria"? Which of course isn't even an option under consideration, only the pre-industrial levels thing is considered, never pre-photosynthesis levels. (Won't somebody think of the archaea?) Why this bias? Because humans like a certain kind of environment with trees and megafauna, that's why. It's a park.

          • culi ・ 8 months ago

            What's your point? This point is completely off topic

            The original comment made it seem like it was a completely arbitrary point of comparison for what "humans like". Instead, the benchmark that is used is what the environment would be like if we took out the massive contributions to global warming and CO2 concentration caused by industrialism

            Are pre-industrial levels "more comfortable" for humans? Sure, maybe I guess. It's probably "more comfortable" for the vast majority of species that are currently adapted for that biosphere. Why does that matter? The point is we're rapidly changing the global temperature levels as well as the co2 concentration rates (and many other environmental "abiotic" factors) at a rate that threatens most of life on earth. Shooting for "pre-industrial levels" as a benchmark is an obvious and easy, if a bit lazy, way to work towards an environment that most of life on earth is already adapted for

  • lupinglade ・ 8 months ago

    Human accelerated change is the concern.

  • hansvm ・ 8 months ago

    Some comics [0] [1] might be able to get the point across in a way that words seldom do when arguing on the interblags.

    You're right to call out that we don't know the "ideal" state of anything. I, for one, am excited about higher mean rainfall, more exotic weather patterns, and the changes in flora and fauna we expect to see as a result. Many species we currently know and love (e.g., basically everything interesting off the west coast of the US or north coast of Australia) will likely be exterminated, but the world will adapt just fine to those new evolutionary pressures. We don't have enough carbon available to create a Venus scenario, so the worst-case probably doesn't kill off all life, and a little chaos can be exciting. I'm sure other people have more sane lists of pros to weigh the cons against, but I try to be honest.

    Whatever the "ideal" state is, or whatever positives we can cook up, there are a number of severe negatives which we've demonstrated time and again we have no idea how to address at a global scale, where just winging it doesn't seem prudent:

    - Much of the currently populated world will be under water. We have a hard enough time housing a few Syrian refugees and El Salvadorean asylum seekers. Where are we going to put all of Florida, the populated halves of Louisiana, Alabama, the Carolinas, Virigina, ...?

    - The frequency and geographic diversity of wet-bulb events will increase substantially. If you're in the wrong place at the wrong time for too long and don't have A/C, you will die. Shade won't save you. Being indoors won't save you. Fans and swamp coolers won't fix it. Beyond the sea level rise, this will render vast swathes of land uninhabitable (like much of India).

    - The frequency and intensity of severe weather events -- straight-line winds, tornados, hurricanes, ... -- will increase. We're expecting 20-40% more CAT4/CAT5 hurricanes by the year 2100. In the US, tornado alley will expand eastward. Much more importantly than all of that, the increased energy and humidity will make storms less predictable (harder to evacuate in time, much more devastating).

    - The impact isn't limited to people. Our crops have been domesticated over hundreds to thousands of years, and GMOs can only do so much to address hardiness when growing soft balls of sugar and starch on a stem (also applies to corn and wheat, not just typical fruits and vegetables). The last thing you want with a growing population, with some of your best crop land being claimed by the ocean, with neighboring crop land being claimed by oceanic storms many years, with that growing population having less space to exist and encroaching inward toward the rest of your crops, is for crops to be harder to grow. Even if 4 years out of 5 are fine, an extra hot spell followed by an extra humid spell is all it takes to kill your tomatoes, eggplants, peppers, and potatoes (or make a huge dent in their yield that year). Other crops have other undesirable weather patterns. There's a chance this is controversial, but I'll posit that mass starvation (above and beyond the current levels of global starvation) every 5-10 years isn't a good outcome.

    And so on. I haven't yet seen anyone try to argue that those negatives are good. Maybe it's a "China hoax" or whatever, but a nicer average climate in Canada (mind you, the extreme weather events will still make most months more unpleasant than the status quo -- averaging weather isn't usually useful) or whatever the proposed upside happens to be won't make up for the cons if the thing is real.

    [0] https://xkcd.com/1732/

    [1] https://xkcd.com/2500/

    • didgetmaster ・ 8 months ago

      All I know is that if the industrial revolution had occurred 20,000 years ago when they estimate that the Boston area was underneath a mile high glacier; the same climate alarmists would have predicted a total catastrophe if the ice age came to an end.

    • southernplaces7 ・ 8 months ago

      You state a great number of very alarming things with all the certainty you can muster, without mentioning that neither you or anyone else actually knows if any of these will come to pass or at least to anything like the degree you mention.

      • hansvm ・ 8 months ago

        In the nicest way possible, do you have anything to add other than just saying that I and the rest of the world are wrong and insinuating that I made a claim I believe to be false?

        There's a lot of uncertainty in the world, but the core claims here aren't particularly hard to understand, and it's not useful to behave otherwise. The effects of the Earth warming are already visible to exactly the degree you would expect from the current level of warming, including wet bulb events, and there's no reason to believe that of all things we don't understand how heat and water work at a macroscopic level and won't see the predicted problems.

    • AStonesThrow ・ 8 months ago

      It's funny/ironic that an active webcomic, whose tagline says it contains sarcasm, and often publishes absurd fake graphs and fake figures, the same comic that is cited here for comic relief and biting insight into nerd topics, the same comic where an entire indepdent wiki has arisen to explain each comic in turn, this comic also once-in-a-while publishes totally serious graphs that are not made-up but based on facts and Randall cites his sources with a straight face, meanwhile writing a somewhat serious blog called "What If?" that tries to distill some absurd question into reality, or at least truth in speculative fiction.

      Art imitates life. Lies, damn lies, and statistics.