In April 1986, a reactor of the Chernobyl Nuclear Power Plant (CNPP) exploded, hurling radioactive material in a vast radius around itself. Known as the worst nuclear accident in history, this disaster resulted in the eventual establishment of a 30-kilometer (about 19-mile) exclusion zone, where habitation and public access are restricted. This restriction is due to the high levels of radioactive contamination in the area. Through a process known as radioactive decay, the contaminants produce ionizing radiation, which is harmful to most organisms because of the DNA damage it can cause. However, it seems that life has found a way to exist in even these harsh conditions. 

Since the 1990s, researchers have begun to discover species of fungi growing in heavily radioactive areas of the CNPP. This was not unexpected, as fungi have been known to survive and grow in all kinds of environments that would be considered hellish for most other organisms, like extreme temperatures, hypersalinity, or extreme acidity or basicity. Even the existence of fungi in radioactive areas wasn’t unheard of–they have been found previously in areas like nuclear testing sites. However, one study noted that some of the fungi not only tolerated the radiation–of the 200 or so fungal species isolated from the CNPP, 86% displayed positive radiotropism, meaning the fungi actively grew towards the radiation. 

Many of these “radiotrophic” fungi share a common trait–they are melanized. This means they contain large amounts of the pigment melanin–the same pigment that colors human hair–in their cell walls, giving the fungi a black appearance. This melanin is apparently what helps the fungi tolerate relatively extreme levels of radiation. Other research suggests the possibility that these fungi can perform radiosynthesis–a process akin to photosynthesis, but which utilizes radiation instead of sunlight and melanin instead of chlorophyll to generate energy. It was found that the radiotrophic strain of Cladosporium sphaerospermum fungi, which was among those found at the CNPP, grew significantly faster while exposed to space radiation compared to the growth of the same fungus on Earth. 

So, what might these radiation-eating fungi be useful for? Some have proposed spaceflight. The greatest hazard to humans in space missions is space radiation, so researchers are on the lookout for any materials that can deflect radiation effectively. In the ISS study mentioned above, it was found that only a 1.67 mm thick layer of the C. sphaerospermum fungus demonstrated a profound ability to shield against space radiation. Compounded with their possible use in radioprotection, these melanized, autotrophic fungi could even be used as a food source for astronauts, as some microbiologists propose. 

Although radiation-consuming fungi are exciting, it is important to remember that many studies in this field still lack support from additional research, and some other studies have cast doubt on previous findings. However, as more attention has been attracted to this field, more exciting results are sure to come, and maybe one day there will be spaceships lined with black fungi traversing the cosmos.