Can Fungi Feed on Radiation?

Can Fungi Feed on Radiation?

Radiotrophic fungi — black, melanin-rich organisms discovered coating the walls of the destroyed Chernobyl reactor — appear to use ionizing radiation as an energy source, a process scientists have proposed calling radiosynthesis.

Discovered Inside One of Earth’s Most Radioactive Places

When a remote-controlled robot camera surveyed the interior of Chernobyl’s ruined Reactor No. 4 in the 1990s, it found the walls blanketed in a thick black biological crust. The April 1986 disaster had released radiation levels lethal to most life on Earth, yet within five years, several species of melanized fungi had moved in — not despite the radiation, but seemingly drawn toward it. Some strains, when observed in laboratory settings, actively grew toward radioactive particles rather than away from them.

The 2007 Study That Changed the Question

In 2007, a team led by Ekaterina Dadachova at the Albert Einstein College of Medicine published results that reframed the conversation. When melanized fungal strains were exposed to ionizing radiation, they grew significantly faster than unexposed control groups. Crucially, the radiation altered the way melanin — the same dark pigment found in human skin and hair — handled electrons. Dadachova’s team proposed that something metabolically meaningful was happening: radiation was exciting electrons in melanin to higher energy states, and the fungi were somehow capturing that energy to drive cellular processes. They named the hypothetical mechanism radiosynthesis, drawing an explicit parallel to photosynthesis in plants.

How Radiosynthesis Might Work

The full biochemical pathway has not yet been mapped, but the leading model works as follows. When ionizing radiation strikes melanin embedded in the fungal cell wall, it boosts electrons to elevated energy states. Those energized electrons are then transferred through molecular chains in a way that mirrors how chlorophyll captures photons during photosynthesis — except the energy source is radiation rather than light. The result, in theory, is a metabolic input that the fungus can use for growth. This would make radiotrophic fungi among the only known organisms to directly harvest energy from ionizing radiation.

Why Would a Fungus Evolve This Ability?

Dadachova herself proposed an evolutionary explanation. Fungi are ancient — their lineage stretches back hundreds of millions of years. During that span, Earth’s magnetic field has periodically weakened or shifted, allowing bursts of ionizing radiation to flood the surface. Melanin may have originally evolved as a shield against that radiation. Over deep time, the same pigment may have been co-opted to extract energy from the very thing it was protecting against — a shift from defense to harvest.

From Chernobyl to the International Space Station

In 2018, researchers sent one of the Chernobyl species, Cladosporium sphaerospermum, to the International Space Station as part of an experiment. A thin biological layer of the fungus measurably blocked a small fraction of the radiation passing through it. The result was modest but significant: a living organism originally found thriving in a nuclear catastrophe had demonstrated potential as a radiation shield in space. Scientists are now exploring whether melanized fungi could one day protect astronauts on long-duration missions — including the journey to Mars.

What Remains Unproven

Radiosynthesis is a compelling hypothesis, not a confirmed fact. No study has yet demonstrated a complete, closed energy cycle — showing that radiation in equals usable chemical energy out, net positive, in the way photosynthesis has been mapped for plants. The observed growth acceleration is real; its exact cause is still under investigation. Independent replication and deeper metabolic tracing are needed before radiosynthesis joins the short list of confirmed biological energy strategies.

Why It Matters

If radiosynthesis is validated, it would expand the known boundaries of life in a fundamental way, adding ionizing radiation to the list of primary energy sources — alongside sunlight, chemical gradients, and heat — that organisms can exploit. It would also have immediate practical applications in space exploration and potentially in nuclear waste environments on Earth. For now, the black fungi of Chernobyl remain one of the most remarkable biological puzzles of the modern era: organisms that turned a human catastrophe into a home.