Part 2 of 2 Parts (Please read Part 1 first)
Tugain’s team hypothesized that the “melanized fungi” might be growing successfully because of the way that melanin interacts with radiation. Their research has confirmed this theory. They found that ionizing radiation altered the structure of melanin molecules in a way that encouraged those fungi to grow faster than identical samples that were not exposed to radiation. The closer the fungi were to the source of radiation, the more melanin they expressed. In short, the black fungi were not growing in spite of radiation; they were growing because of it.
Additional research by Tugai, Zhdanova, and John Dighton of Rutgers University found that fungal bodies containing melanin were actually attracted to radiation. This phenomenon is called “positive radiotropism”. It is “the capability of fungal organisms to sense radioactivity and grow directionally toward the radiation source.” The Berkeley National Lab microbiologist Tamas Torok had samples of these radiation-resistant fungi in his lab for years. He notes that the process isn’t really analogous to metabolism or photosynthesis. Instead, it is another form of energy conversion.
Ekaterina Dadachova and Arturo Casadevall of Albert Einstein College of Medicine of Yeshiva University created a team and acquired some samples of the black fungus. They confirmed the Ukrainian team’s conclusion that melanin was behind the black fungi’s unique ability to thrive with radiation. Casadevall said, “We began to expose the fungi to radiation. What we noticed was they would grow faster, and this was associated with melanin. If they didn’t have melanin, you didn’t see the effect.”
The implications of this research are incredible. In 2016, SpaceX and NASA sent samples of melanized fungi into space to see if it could mitigate radiation there. In a peer-reviewed study published in BioRxiv in 2020, they reported that the fungi could cut radiation levels in space by about two percent. The black fungi could potentially “negate the annual dose-equivalent of the radiation environment on the surface of Mars.” This would make it easier for astronauts to live in space.
Melanized fungi could also play a critical role here on Earth. Further research by Dadachova and her team have proposed that a unique relationship between fungi, melanin, and radiation could proved new insights into to ways to reduce radiation and generate energy in a warming climate. It could also help in the case of another nuclear disaster. Tugai wrote, “To date, a significant amount of [radioactive] hot particles have already decomposed under the action of soil fungi. This indicates that microbiological processes can play a decisive role in the processes of destruction and migration of radionuclides in the environment.” Torok notes that while radiation cannot be completely bioremediated or removed from the environment by biological action, the black fungi can help immobilized some of it. The fate of Chernobyl is still of grave concern and unique solution could still be necessary.
Black fungi continues to grow inside the Chernobyl reactors and in the radioactive soil around them. When she first went to the exclusion zone, Tugai found that while most of the soil had been cleared of the majority of radiation through brutal, labor-intensive cleanup. “no one touched the soil around the cemetery where the level of background radiation is still dozens of times higher than the norm. When radiation first hit the area around Chernobyl, it caused some of the pines in and near the cemetery to turn red, creating the infamous Red Forest. It later became a burial ground for particularly radioactive tree trunks. Over the years since the disaster, new trees have grown amid the graves and birds now fly and sing in their branches. Deep in the soil, webs of black fungi pass signals through roots as they “alchemize” radiation, transforming it into something new.