Mars can host life—even in its present state—according to Polish researchers, after demonstrating lichen’s survival under simulated Mars-like conditions.
Even when exposed to ionizing radiation similar to that bombarding the Martian surface, the lichen remained metabolically active. The research challenges long-held assumptions about Martian habitability, redefining astrobiology, and future expectations for space exploration.
Lichen Resilience
While the study doesn’t suggest that a wide variety of life could thrive on Mars, it does highlight the exceptional resilience of Earth lichen, which grows in extreme environments such as arid deserts and frozen polar regions. With low metabolic rates, minimal nutritional needs, and exceptional longevity, lichens are highly tolerant of environmental stressors. Their ability to regulate water usage also allows them to survive long periods with little to no water. These plantlike organisms often grow on tree bark and rocks and are known to enrich soil in new ecosystems. In nature, their hardiness includes the ability to absorb pollutants, making them useful for monitoring air quality.
This resilience stems from the fact that lichens are symbiotic organisms composed of fungi and algae or cyanobacteria. Fungi play a key role in decomposing matter, creating nutrients for algae, which in turn sustain the fungi through photosynthesis. In this study, it was specifically the fungal component of the symbiotic partnership that withstood simulated Martian darkness and a year’s worth of X-ray radiation modeled on periods of intense solar activity.
Simulating Mars
A team of researchers at Poland’s Jagiellonian University investigated previous suggestions that lichens—extremophiles by nature—may be well-suited to survive in extraterrestrial environments. Earlier studies had placed lichens in Mars-like conditions, but without accounting for ionizing radiation, one of the planet’s most formidable threats to life. In this study, scientists used two lichen species with markedly different traits: Diploschistes muscorum and Cetraria aculeata. The five-hour experiments simulated Martian atmosphere, pressure, temperature variations, and X-ray radiation.
Despite earlier assumptions that Mars’s intense X-ray radiation from solar flares and energetic particles was incompatible with life, D. muscorum proved remarkably resilient. Its defense mechanisms held up well under simulated Martian conditions, with its heavy crystalline deposits potentially aiding its survival. This finding offers hope and a new framework for exploring extraterrestrial microbes and potential symbiotic survival strategies.
“Our study is the first to demonstrate that the metabolism of the fungal partner in lichen symbiosis remained active while being in an environment resembling the surface of Mars,” said lead author Kaja Skubala. “We found that Diploschistes muscorum was able to carry out metabolic processes and activate defense mechanisms effectively.”
Colonizing the Red Planet
On Earth, lichens are known to colonize nutrient-poor substrates, enriching them for other species to follow. Despite the harsh Martian environment, there remains the possibility of liquid water under specific conditions. The lichen’s ability to colonize and survive radiation exposure makes it a compelling candidate for assessing Mars’s habitability.
“These findings expand our understanding of biological processes under simulated Martian conditions and reveal how hydrated organisms respond to ionizing radiation – one of the most critical challenges for survival and habitability on Mars,” Skubala continued. “Ultimately, this research deepens our knowledge of lichen adaptation and their potential for colonizing extraterrestrial environments.”
Looking ahead, the team recommends a two-pronged approach: continuing to explore the mechanisms behind lichen’s radiation resistance and testing lichen in situ on the Martian surface.
The paper “Ionizing Radiation Resilience: How Metabolically Active Lichens Endure Exposure to the Simulated Mars Atmosphere” appeared on March 31, 2025 in IMA Fungus.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.