The mysterious black fungus from Chernobyl that may eat radiation

4 hours ago (bbc.com)

This would be a cool origin story for astrophage (from Project Hail Mary, a fun & light sci fi read by the Martian guy)

  • There is a movie coming with Ryan Gosling, I sure hope they keep the spirit of the book and don't turn that into some bizarre hollywoodish cash grab

    • I think the Martian was adapted well from book to movie, so I have hope for this one. That said, compressing the entire story into a theatre runtime is tricky: I think it would be a win if only half of the character and relationship growth of the two ship bound protagonists comes through in the adaptation (because it was sooo good in the book!)

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  • Also this is how the protomolecile from The Expanse feeds. It can absorb pretty much any radiation across the whole spectrum.

    • I was thinking the same thing. That one accelerates its growth in the presence of radiation. But it also seeks out human flesh and brains to build its biomass intelligence blob, unfortunately.

I feel like I'm taking crazy pills every time I read about this fungus. Let us grant the premise of a fungus somehow harnessing ionizing radiation using melanin; such a fungus could in principle be used to shield radioactive sources, but it won't "eat it up"; the radioactive isotopes emitting that radiation won't be disposed of in any way by the fungus. They don't eat those, and even if they did it wouldn't get rid of them, only incorporate them. Neither chemical nor any kind of biological process can make radioactive isotopes stop being radioactive, you need some sort of nuclear process to do that. The absolute best the fungus could do is bind up the radioactive isotopes to aid in their collection, but epoxy resins sprayed over the contaminated areas are far more effective than that could ever be.

Also, making spacecraft shielding and even furniture out of this stuff? It's the stupidest thing I ever heard. The mass of the fungus doesn't come from ionizing radiation anymore than the mass of a plant comes from sunlight. You might as well claim that you're going to grow trees in space using the abundant sunlight. They power themselves with light but still need to be made out of something! Are they also hoping these fungus like to eat lunar regolith? It makes zero sense, but here we've got the BBC and apparently NASA taking the idea seriously. Where is the fucking biomass meant to come from?? I must be crazy, or they all are.

  • Melanin is used as a solar panel, capturing gamma rays and then passing the resulting consistent flow of excited electrons over to the Krebs cycle with the help of CO2; like in photosynthesis. Humans run on electrons resulting from Krebs cycle as well, just the input is different. By using it as shielding, you'd simply decrease the amount of ionizing radiation hitting humans inside the spaceship. In other words, it would be better than some static material as it consumes part of incoming radiation for its own existence.

  • In regards of NASA taking it seriously, my null hypothesis would be that reporters misunderstand NASA just as much as everything else about fungi.

    If I understand the linked NASA press releases correctly, they are talking about using a mix of regolith, cyanobacteria and fungi as part of the outer shell of a habitat. The mycelian network of the fungi binds the loose regolith together, forming a strong and somewhat flexible material, with the fungus working a bit like the cement in a concrete mix. And because fungi don't form from nothing you add cyanobacteria that create "fungus food" (presumably some sugar) from water and CO2 (I'm sure you need to add a bit more than that, but that might be beyond the scope of a press release)

    This really has nothing to do with radiation-absorbing fungi at all, except for one remark how the melanin in radiation-eating fungi could provide further shielding.

  • >the radioactive isotopes emitting that radiation won't be disposed of in any way by the fungus. They don't eat those, and even if they did it wouldn't get rid of them

    Please excuse the novice question but I am confused, where does the energy come from then?

    • Granting the premise, the fungus gets energy (but not mass) from the natural decay of radioactive particles. It doesn't accelerate that decay, the decay happens at the same pace it would have without the fungus. Just like planting more plants doesn't make the sun burn out any faster. The fungus itself is made of carbon and all the other usual stuff life is made from.

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  • I mean... you're completely right and some of the stuff is as ridiculous as you're suggesting (e.g. the furniture). However... what we're agreeing on is that the fungus is absorbing alpha/beta particles and gamma rays that are coming off the radioactive material, which in theory should mean that it would act as a radiation shield. Whether it's a more effective radiation shield than other options is the big question, and for space travel in particular the question I'd want to know is how effective is a given mass of this fungus relative to other options (e.g. water).

    • Id like to know about its failure modes. Does the fungus die when kept in less than ideal conditions? How quickly?

  • Something the fungus COULD do (in a hypothetical world) is concentrate radioisotopes along with some moderator to accelerate the fission process and harvest more energy.

    Would probably require a lot more time than it would have, however, considering the relatively low amounts of radioisotopes in todays world (due to the halflife of most of them, and the age of our planet).

    Several billion years ago it could have been a thing though!

    • But if it concentrates isotopes to accellerate fission, wouldn't that cause the material to heat up and, ultimately, kill the fungus? Depends on rate of concentration of course, if it just grabs the odd airborne isotope (if that's a thing) then maybe.

    • Maybe in principle, but neutron radiation from fallout/etc is relatively minimal and you really just have to wait out the decay of those isotopes.

      The good news is radiation detectors are insanely sensitive so you can map where the hotspots are and mitigate much of the risk using exclusion zones and / or various cleanup techniques to collect the radioactive material so it can be safety stored.

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I wonder if you could power something of this? If the fungus have some type of melanin that will turn ionized radiation into energy, could we then use that to power something of background radiation?

Also interesting to see how close this fungi will grow to the radiation source, or will it be able to mutate to completely envelop the radiation source.

  • Just dry the fungus and burn it. The process is fairly analogous to photosynthesis in plants, so we've basically already been doing this since we learned to make fire, just with a different source of radiation.

I did some basic calculations to compare the energy in the radiation vs the energy required to grow 10% extra.

- If we assume they are working in the reactor we get radiation levels of something like 1 mGy/hour. But we can prop this up to mabye 500 mGy/hour since i dont know how they grew their culture

- That leads to 0.05 J of extra energy per gram of microbial bio material.

- Energy needed to grow 1g of microbial biomaterial ≈ 3.15 kJ 10% of that is 315 J per gram

The result is that:

The amount of radiation energy available is 4 orders of magnitude too small to power even a 10% growth boost.

Edit: updated with more accurate estimations.

  • Add in some evolutionary strategies, and you have the recipe for a good sci-fi book: a fungus in Chernobyl rapidly outpaces its competitors due to its ability to absorb radiation. Each iteration grows and reproduces faster, until it is so blindingingly fast that it begins to outpace the output the fuel rods produce.

    The world rejoices as this fungus is perfect for cleaning up nuclear waste products, until we realize that it evolved to function outside of Chernobyl and begins to eat everything it can reach. Mankind launches into a desperate struggle for survival as the fungus lays waste to large swathes of land.

    • They don't eat the radioactive material and make it not radioactive.

      [Assuming they use the radiation to get energy [1].] They just wait patiently until the radioactive atoms decay and emit radiation, like a gamma ray, and then absorb the gamma ray and use the energy. The half life of the radioactive material does not change.

      [1] I still doubt this claim, but let's go along assuming the best case.

    • Some similar concepts are found in The Expanse for those who have not read/seen it.

    • Some fungi are already the largest organisms on earth at >200 km^2

      Armillaria ostoyae ( https://en.wikipedia.org/wiki/Armillaria_ostoyae )

      Consider when organisms must pass, that these ancient fungi likely still consume the host... Thus, on a 8000 year timescale most fungi doesn't necessarily need to pursue food that naturally dies in around a century.

      Yeasts are already sharing your body along with numerous other organisms that are often harmless or even beneficial. Best not think about it too much if you are uncomfortable with seeing yourself as a mini ecosystem. =3

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  • I'm not sure where you're going with this, but since they have actually researched how it grows, I think it's more likely your calculations/assumptions are incomplete.

    For example:

    > Energy needed to grow 1g of microbial biomaterial

    based on what?

    Edit: Maybe you meant that radiation alone wouldn't be enough for that growth, so there'd be other components that it's helping with.

    • Initially i asked a AI for standard values but here is a proper source:

      - Negentropy concept revisited: Standard thermodynamic properties of 16 bacteria, fungi and algae species ( https://arxiv.org/abs/1901.00494)

      > Maybe you meant that radiation alone wouldn't be enough for that growth, so there'd be other components that it's helping with.

      Yes. Clearly it grew as it grew, but the question is what drove/powered the growth.

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  • Right, it could be a lack of competition in the direction of the reactor. It's a giant petri dish for anything able to withstand radiation.

  • > That leads to 0.05 J of extra energy per gram of microbial bio material

    Over what timeframe? If that’s 0.05 J per hour and “the researchers found that fungi that faced the galactic cosmic radiation for 26 days grew an average 1.21 times faster” 26 * 25 / 21% and the numbers don’t look that unreasonable.

    • I calculated over 5 days. Which was just a guess.

      But i focused on the 10% mentioned.

      That said time could be factored out if you did everything properly.

  • I also did some back of the envelope calculations. Here's what I got: the radiation level just 1 meter away from the "elephant foot" (the solidified molten core), at the time of the accident was about 1000 times lower than the solar irradiation. At 100 meters it was 10 million times lower (because of the inverse square law). Now, the radiation from the elephant foot has decreased significantly. I couldn't find a recent estimate, but I would expect it to be at least 100 times lower. So at 100 meters from the elephant foot, the radiation level is a billion times lower than what you get from the sun. There's no way any organism can "feed" on that.

    • > Here's what I got: the radiation level just 1 meter away from the "elephant foot" (the solidified molten core), at the time of the accident was about 1000 times lower than the solar irradiation. At 100 meters it was 10 million times lower (because of the inverse square law).

      No, the elephants foot isn’t a point source at its surface.

      To use an extreme example going from 1m away from the sun to 100m away from the sun doesn’t result in a 10,000x drop off in energy density. Instead the exponential drop-off occurs relative to the center of the sun because energy is coming from any point on the surface visible to that location. A similar principle applies with the elephants foot, though the geometry is more complicated.

  • There's another parameter worth considering - how efficient is it to convert sunlight vs. gamma radiation into biologically usable energy.

    What if for some reason gamma radiation changes the equilibrium constants for ADP --> ATP?

    • Another hypothesis to test would be if the radiation is being used as a catalyst somehow.

      E.g. Could be denaturing something else, unlocking a previously inaccessible energy source. Possibly some radiochemistry creating a new food source for the fungus too.

  • Yeah, from that it sounds like the main advantage of this mold is that it gets some compensation from all that deadly radiation, and thus does better than mold which doesn't.

The article talks about fungi been attracted to ionising radiation. Per wikipedia:

https://en.wikipedia.org/wiki/Ionizing_radiation

Ionizing (or ionising) radiation is particle or photon that has enough energy to detaching electron from atoms or molecules. So it includes all the usual high energy radiations such as Gamma, X-rays, high energy UV, alpha, beta, neutron et al.

I'm skeptical just because I know someone who has been working on the problem of radioactivity for like 30 years and they have left no stone unturned in that undertaking.

> Zhdanova suspected that the melanin of these fungi was acting as a shield against ionising radiation.

Wouldn't that be very easy to measure? My guts tell me that using the melanin as a shield against gamma radiation has a negligible effect, if any at all.

  • You are assuming a molecule good at shielding against UV light is probably a poor shield against gamma rays, many orders of magnitude shorter wavelength. That sounds probable ...

    But how about the theory that systems to clean up smashed up proteins from UV light is also good to clean up smashed up proteins from gamma radiation?

    And one of the parts of that system, or upregulated with that system, is melanin.

Imagine if this fungus and its radiation eating abilities was the key to interstellar travel.