Science Monday! When life throws you gamma rays

About ten years ago, a research team sent a remote vehicle down into the reactor pit at the old Chernobyl nuclear plant. You know, just to say hi and see how things were going.

Hey there, frozen pile of once-molten rock and nuclear fuel lava! Long time no see!

When you’re deep in the heart of an area spewing out enough radiation that rad suit-clad workers building a new containment sarcophagus are only allowed to work five-hour days, you expect pretty sterile surroundings. So you can imagine the scientists’ surprise to see the walls covered in gooey black stuff… that looked suspiciously like the crud growing in a bachelor pad shower.

That that black goo indeed turned out to be made of three common species of fungi: Cryptococcus neoformans, Wangiella dermatitidis, and Cladosporium sphaerospermum.  (Warning: don’t image search these right now if you’re trying to eat.) Some strains of these species apparently had adapted to live in extremely high-radiation environments. But these fungi weren’t content to just survive.

They were eating the radiation.

Run, puny human!

Evidently these fungi grew pretty slowly when they were brought back to the lab. Somebody got the bright idea to try putting the samples in a box with a source of gamma radiation inside. Bingo! The fungi perked right up. Later MRI scans showed that the radiation exposure was altering the spin state of atoms inside molecules of melanin in the fungus. In other words, melanin was intercepting the radiation, and the fungus was somehow turning that energy into growth.

These badass Basidiomycota had learned how to photosynthesize. Not with normal visible light like plants do, mind you. With motherloving GAMMA RADIATION.

The revelation that it’s possible for some life forms to not only live in the presence of high levels of gamma radiation, but to put it to constructive use, brings up a lot of really interesting possibilities. None of the fungi at Chernobyl make edible mushrooms. In fact all three of them are opportunistic human pathogens– if you didn’t listen when I said “Don’t look for pictures of these if you’re trying to eat,” by now you know why! C. sphaerospermum is also a common cause of sick building syndrome. It’s almost like… Chernobyl doesn’t want us back?

Despite radiation, with humans gone wildlife like these reintroduced Przewalski’s horses are thriving near old Chernobyl

But now we know it may be possible to develop edible fungi with a high melanin content that can intercept cosmic rays and turn it into deliciousness. One can only imagine how useful it might be to have a sun-fuelled protein recycling system in space.

Other nifty uses for melanized fungi here. Article on physiology of the Chernobyl radiotrophic fungi here.