Mojave Lichen's Survival Under UVC Radiation Suggests Life on Exoplanets

In a groundbreaking study published on June 12, 2025, in the journal *Astrobiology*, researchers from the Desert Research Institute (DRI) demonstrated that a lichen species native to the Mojave Desert, *Clavascidium lacinulatum*, can endure extreme levels of UVC radiation, illuminating new possibilities for life on exoplanets. This research highlights the resilience of life and its potential adaptability to harsh extraterrestrial environments.

The study was spearheaded by Dr. Henry Sun, an Associate Research Professor of Microbiology at DRI, alongside graduate student Tejinder Singh. Their observations began with a curious inquiry into the black appearance of the Mojave lichen, which typically contains chlorophyll but does not exhibit the expected green coloration. This led to the discovery that the lichen possesses a natural protective layer, akin to a microscopic "sunscreen," capable of safeguarding its vital cells from lethal radiation.

Lichens are unique organisms formed from the symbiotic relationship between fungi and algae or cyanobacteria. According to Dr. Sun, this study not only sheds light on the evolutionary adaptations of life on Earth but also prompts critical questions regarding the potential for life on planets that revolve around stars emitting strong solar radiation. Many of these exoplanets, particularly those orbiting M and F-type stars, are subject to intense UVC radiation, which, on Earth, is filtered out by the atmosphere.

The research involved placing the lichen under a controlled UVC light source for three months. Remarkably, about 50% of the algal cells remained viable and capable of replication upon rehydration. This finding suggests that if similar life forms exist on exoplanets, they might also have developed mechanisms to withstand extreme radiation.

Dr. Christos Georgiou, a researcher at the University of Patras, also contributed to the study, examining the chemical properties of the lichen's protective layer, which appears to function similarly to UV-resistant additives used in plastics. The findings indicate that the protective layer not only shields the cells from direct radiation but also mitigates harmful chemical reactions that could result from intense solar exposure.

The implications of this study extend far beyond the Mojave Desert. Tejinder Singh, now at NASA Goddard Space Flight Center, emphasized that the extraordinary resilience of these lichens offers a glimpse into the tenacity of life under even the most inhospitable conditions. This research may inspire future explorations into the habitability of exoplanets, particularly those identified by the James Webb Space Telescope, which has shifted the focus of astrobiological research toward these distant worlds.

The study's findings raise significant questions about the potential for microbial life elsewhere in the universe, particularly on planets that have liquid water and atmospheres suitable for life. As the understanding of these organisms advances, scientists may be able to identify biosignatures indicative of life on other planets. The researchers concluded that if life can persist under such extreme conditions, it not only expands the definition of habitable environments but also underscores the resilience of life itself.

This study represents a pivotal moment in astrobiology, providing a basis for further research into the limits of life and the conditions necessary for it to thrive in the cosmos. As humanity continues to explore the vastness of space, the findings from Mojave lichen may one day aid in the quest to discover life beyond Earth.