Nearly 40 years after the Chernobyl Nuclear Power Plant disaster, scientists have discovered that the exclusion zone is not devoid of life. Inside the highly radioactive remains of the reactor, distinct forms of life have adapted and thrived. Specifically, a community of fungi clinging to the interior walls appears to utilize the lethal environment to its advantage.

The Radiosynthesis Hypothesis

The primary subject of this research is a black fungus named Cladosporium sphaerospermum. Unlike typical organisms that suffer DNA damage from ionizing radiation, this fungus flourishes in it. Researchers suggest that the fungus uses its dark pigment, melanin, to harness ionizing radiation and convert it into chemical energy. This theoretical process, known as radiosynthesis, functions similarly to how plants use chlorophyll to convert sunlight into energy via photosynthesis.

Key Findings and Experiments

Research into this phenomenon began in the late 1990s when microbiologist Nelli Zhdanova discovered 37 species of fungi in the reactor's shelter, many of which were rich in melanin. Subsequent studies led by Ekaterina Dadachova and Arturo Casadevall revealed that:

• Exposure to ionizing radiation does not harm C. sphaerospermum; instead, it accelerates its growth.
• Fungal melanin may act as both an energy harvester and a protective shield against radiation damage.
• In a 2022 experiment aboard the International Space Station (ISS), the fungus demonstrated the ability to block cosmic radiation, suggesting potential applications for radiation shields in space travel.

Scientific Uncertainty

Despite the promising observations, the specific biological mechanism remains unproven. While the fungus grows better under radiation, scientists have yet to demonstrate a defined energy-harvesting pathway or carbon fixation dependent on ionizing radiation. Some experts, such as engineer Nils Averesch, caution that while the fungus is undoubtedly resistant, actual radiosynthesis is still a theory. It is also possible that the observed growth is a stress response rather than a direct metabolic adaptation.

Conclusion

While the exact mechanics remain a mystery, the resilience of C. sphaerospermum highlights the incredible adaptability of life. Whether through energy harvesting or extreme stress response, this fungus has found a way to proliferate in one of the most dangerous environments on Earth, offering potential insights for biotechnology and space exploration.

Mentoring question

How might the discovery of biological mechanisms that harness hazardous energy sources, like ionizing radiation, influence future innovations in sustainable energy or space exploration technology?

Source: https://www.sciencealert.com/chernobyl-fungus-appears-to-have-evolved-an-incredible-ability