In the ruins of Chernobyl’s shattered reactors, something unexpected has taken root. Thick black mats of mold are thriving where radiation levels would shred human DNA, turning abandoned nuclear sites into laboratories for one of biology’s strangest survival strategies. Instead of merely enduring the fallout, these fungi appear to be using the radiation itself as a source of energy and growth.
What began as a curiosity on the walls of a destroyed reactor has become a serious line of research, with scientists probing how this “radiation diet” works and whether it can be harnessed. I see a story that stretches from the concrete sarcophagus in Ukraine to the International Space Station and even to future Mars bases, where the same organisms that colonized Chernobyl’s hot zones might one day help shield astronauts from cosmic rays.
Inside the ruined reactors, a new kind of colonist
When engineers and researchers finally gained regular access to the most contaminated corners of the Chernobyl Nuclear Power Plant, they expected corrosion, dust and silence, not a living carpet. Yet on control room walls, reactor piping and concrete surfaces, they found dark, velvety growths of mold clustered most densely where radiation readings were highest. In places where humans can spend only minutes without heavy shielding, these fungal colonies had quietly spread for years, turning the wreckage into a thriving microhabitat.
One of the first species to draw attention was a black mold called Cladosporium sphaerospermum, which researchers linked to unusually rapid growth in high-radiation zones inside the plant. A study in Mycological Research described how this organism, along with other sooty molds, formed thick biofilms on reactor surfaces and appeared to grow faster when exposed to intense gamma rays, a pattern that led scientists to describe them as Radiation Eating Fungi. The key clue was the abundance of dark pigment in their cell walls, a hint that the same melanin that colors human skin might be doing something far more radical inside these spores.
The mysterious black mold that followed the fallout
Long before the global spotlight turned back to Chernobyl’s wildlife, Ukrainian mycologist Natalia Zhdanova was tracking an unassuming but relentless invader. As exclusion-zone checkpoints kept people out, Zhdanova’s black mould crept in, colonising abandoned buildings, soil and even the interior of the damaged reactor itself. Over time, the once-sterile industrial spaces became streaked with inky growth, a visual record of how life was reclaiming one of the most contaminated places on Earth.
Field work in the zone showed that this mould, formed from dense mats of melanised hyphae, was not randomly distributed. It clustered along radiation gradients, thickening on surfaces that emitted the strongest gamma flux and thinning where levels dropped. Reporting on this work has highlighted how Zhdanova’s observations, later joined by images from researchers such as Germán Orizaola and Pablo Burraco, helped establish that the black fungus was not just surviving but actively seeking out radioactive niches, a pattern described in detail in coverage of the mysterious black fungus that had spread within the exploded reactor building.
From disaster zone to “healing” ecosystem
Nearly four decades after the explosion, the Chernobyl exclusion zone has become a paradoxical landscape, where high radiation coexists with flourishing forests, wolves and wild horses. Within that recovering ecosystem, the black fungus has emerged as a kind of biochemical recycler, intercepting ionising energy that would otherwise slam into soil microbes, seeds and animal tissue. By soaking up part of that radiation and converting it into its own growth, the mold effectively diverts some of the destructive power into biomass.
Researchers who sampled the ruins have described how, in the shattered reactor halls of Chernobyl, the fungus forms a living patina over concrete and metal, slowly binding radioactive particles into organic structures. One account framed this as a kind of slow-motion remediation, suggesting that a black fungus might be “healing” Chernobyl by drinking radiation and incorporating radionuclides into its tissues, a process documented in detail in work on how Chernobyl’s ruins became a test bed for this unusual metabolism. I see that idea as less mystical than it sounds: the fungus is not cleansing the site overnight, but it is changing how and where the radiation interacts with living matter.
What “radiotrophic” really means
To make sense of what is happening on those reactor walls, scientists coined a term that still sounds almost science fiction: radiotrophic. Radiotrophic fungi are defined as organisms that can perform radiosynthesis, using ionising radiation as an energy source in a way that loosely parallels how plants use sunlight. Instead of chlorophyll, these fungi rely on melanin, a pigment that appears to change its electronic state when bombarded with gamma rays, potentially allowing cells to capture some of that energy for metabolism.
Laboratory experiments with Chernobyl isolates have shown that melanised strains grow more robustly in radiation fields than non-melanised controls, and that their melanin chemistry shifts under exposure in ways consistent with energy transfer. The concept of radiotrophic growth, once speculative, is now grounded in repeated observations of fungi collected from the Chernobyl Nuclear Power Plant and other contaminated sites, as summarised in reference material on Radiotrophic fungi. I find it striking that the same pigment that protects human skin from ultraviolet light may, in these organisms, double as a microscopic solar panel tuned to gamma rays.
More than one mutant: a whole community of radiation lovers
It would be tempting to treat the Chernobyl mold as a one-off curiosity, a single mutant that lucked into a bizarre niche. The reality is more complex and, in some ways, more unsettling. Surveys of the reactor and surrounding high-radiation soils have isolated a diverse cast of fungi, many of them darkly pigmented and many showing similar tendencies to grow toward or along radioactive materials. Rather than a lone survivor, Chernobyl hosts an entire guild of organisms that appear comfortable in conditions that would sterilise most life.
One synthesis of this work notes that this is not a one-off mutant and that Over 200 species of fungi have been isolated from the reactor and the highly radioactive Red Forest, including genera such as Cladosporium, Alternaria, Paecilomyces and even Cryptococcus neoformans. In my view, that diversity matters: it suggests that radiotrophy is not a freak accident but a trait that multiple lineages can evolve or amplify when the environment rewards it, turning nuclear ruins into evolutionary playgrounds.
How the mold reshaped Chernobyl’s food web
With humans largely out of the picture, the Chernobyl area has become an unplanned experiment in how ecosystems reorganise around radiation. Wildlife cameras now capture wolves, lynx and wild boar moving through landscapes where Geiger counters still crackle, and beneath their feet, fungal networks are quietly mediating how radionuclides move through soil and plants. The black mold and its radiotrophic relatives sit at the base of this altered food web, intercepting contamination before it reaches seeds, roots and grazing animals.
Field observations have shown that these molds grow most densely in highly irradiated areas, coating surfaces and debris that would otherwise act as direct sources of exposure for insects and small mammals. Reporting on how Chernobyl mold has learned to eat radiation describes how this dense colonisation effectively creates a biological buffer, with the fungi absorbing and redistributing some of the energy and radionuclides. I see that as a reminder that even in a damaged landscape, the basic logic of ecology still applies: whoever controls the flow of energy, even radioactive energy, shapes who can live there.
From exclusion zone to space lab
The leap from a ruined Soviet reactor to outer space might sound dramatic, but for researchers studying radiotrophic fungi, it is a natural progression. If a thin layer of mold can thrive on the walls of Chernobyl’s reactors, then perhaps a similar layer could help protect spacecraft or habitats from cosmic radiation. That idea has moved from speculation to experiment, with teams isolating Chernobyl strains and testing how well they block or absorb radiation in controlled settings.
One widely discussed proposal envisions using these fungi as living shields for long-duration missions, with a thin, self-repairing layer of melanised biomass lining spacecraft walls. Coverage of this work has described how scientists hope to use radiation-eating fungi from Chernobyl to protect future Mars colonizers from cosmic radiation, building on the observation that Scientists Find Radiation Eating Fungi At Chernobyl And Now Seek To Harness Their Power For Space. For me, the appeal is obvious: unlike passive shielding, a fungal layer can grow, heal and adapt, turning a hazard into a resource.
Testing the fungi in orbit
To move beyond theory, researchers have already taken Chernobyl-derived fungi into orbit. An experiment conducted on the International Space Station exposed eight fungal species, including Cladosporium molds, to the station’s radiation environment to see how they responded. The results were striking: several of the melanised strains not only survived but seemed to prefer radioactive surfaces, spreading more readily where the flux was highest and hinting that their radiotrophic traits were active even in microgravity.
Accounts of this work describe how the ISS experiment treated the station as a kind of orbital Chernobyl, using its constant drizzle of cosmic rays as a stand-in for the gamma fields back on Earth. Reporting on radiation-resistant mutants at Chernobyl notes that the International Space Station, or ISS, provided a unique platform to test whether these organisms could function as living shields, and that some of the International Space Station samples, particularly the ISS Cladosporium moulds, seemed to prefer radioactive surfaces. I read that as an early proof of concept that what evolved in a Ukrainian reactor can operate just as well in orbit.
Life finds a way, even on the ISS
The ISS experiments also offered a more philosophical lesson: life is remarkably good at exploiting any available energy gradient. On Earth, that usually means sunlight or chemical reactions. In orbit, for a handful of fungal strains, it may mean cosmic rays. One analysis of the ISS work drew a direct line from the famous “life finds a way” line in Jurassic Park to the discovery that the same fungus found at Chernobyl could grow under space radiation, using melanin in a role analogous to chlorophyll in plants.
In that framing, the fungus becomes a kind of dark photosynthesiser, with melanin capturing ionising radiation and helping convert it into biochemical energy, much as chlorophyll converts visible light into glucose and oxygen. A detailed discussion of this idea in a piece titled Life Finds A Way: Radiation Eating Fungus on the ISS explains how the Life Finds Way Radiation Eating Fungus ISS experiments compared melanin’s behaviour to that of chlorophyll. For me, that comparison drives home how little we have explored the full range of metabolisms that life can evolve when pushed into extreme environments.
A “nuclear shield” for Mars missions
As space agencies and private companies sketch out plans for Mars missions, radiation remains one of the hardest problems. The thin Martian atmosphere and lack of a global magnetic field leave astronauts exposed to a constant barrage of high-energy particles. Traditional shielding, such as thick aluminium or water walls, is heavy and expensive to launch. That is where the Chernobyl fungi re-enter the picture, not as contaminants but as potential partners.
Recent reporting has described how a peculiar black fungus discovered in the Chernobyl exclusion zone can block a significant fraction of incoming radiation when grown as a thin layer, leading some researchers to describe it as a kind of “nuclear shield”. One analysis argues that this Chernobyl fungus could be a breakthrough for Mars missions, with the idea that a living, self-thickening layer of melanised biomass could protect astronauts on Mars missions while continuously repairing micrometeoroid damage. I see that as a radical shift in thinking: instead of sealing life out of our spacecraft walls, we might one day grow our protection from the same organisms that once colonised a ruined reactor.
The mold that eats radiation for breakfast
For clinicians and biologists alike, the Chernobyl fungi have become a case study in how adaptable pathogens and environmental molds can be. A deep dive into their biology, framed around Episode 114 – The Mold that Eats Radiation for Breakfast, walks through how melanin-rich cell walls, efficient DNA repair and flexible metabolism combine to let these organisms shrug off doses that would be lethal to humans. The story is not just about one species, but about a broader fungal toolkit for surviving in hostile environments.
In that discussion, the hosts of Episode 114 emphasise that The Mold that Eats Radiation for Breakfast is not a superhero but a reminder that evolution rarely leaves energy on the table. Much of the analysis focuses on how traits that already existed for UV protection or oxidative stress response could be repurposed for radiotrophy once the right selection pressure appeared, a theme explored in detail in Episode 114 The Mold Eats Radiation for Breakfast Much of the commentary. When I look at Chernobyl’s black mold through that lens, I see less a monster born of disaster and more a survivor that found a way to turn catastrophe into opportunity.
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