Cetraria aculeata superimposed on Mars. Credit: Lichen: Skubała et al. Design: Pensoft Publishers. CC BY.
A new study has shown lichens have survived a Mars simulation in what could represent a step towards life on the red planet.
For the first time, researchers have demonstrated that certain lichen species can survive Mars-like conditions, including exposure to ionising radiation, while maintaining a metabolically active state.
The new study highlights the potential for lichens to survive and function on the Martian surface, challenging previous assumptions about the uninhabitable nature of Mars, and offering insights for astrobiology and space exploration.
Lichens are not a single organism, but a symbiotic association between a fungus and algae and/ or cyanobacteria known for their extreme tolerance to harsh environments such as Earth’s deserts and polar regions.
In this study, the fungal partner in lichen symbiosis remained metabolically active when exposed to Mars-like atmospheric conditions in darkness, including X-ray radiation levels expected on Mars over one year of strong solar activity.
The research focused on two lichen species, Diploschistes muscorum and Cetraria aculeata, selected for their differing traits, exposing them to Mars-like conditions for five hours in a simulation of the planet’s atmospheric composition, pressure, temperature fluctuations, and X-ray radiation.
Experiment arrangement of vacuum chamber with the additional facility, including metal grate with lichens, cooling table, temperature, pressure and humidity sensors, X-ray lamp with the controller, CO2 valve with cylinder, controllers of vacuum chamber, pressure, cooling table, and computer. Credit: Skubała et al. CC BY.
Potentially survive
The findings suggest that lichens, particularly D muscorum, could potentially survive on Mars despite the high doses of X-ray radiation associated with solar flares and energetic particles reaching the planet’s surface.
These results challenge the assumption that ionising radiation is an insurmountable barrier to life on Mars and set the stage for further research on the potential for extraterrestrial microbial and symbiotic survival.
Lead author of the paper, Kaja Skubała, said: “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.
“We found that Diploschistes muscorum was able to carry out metabolic processes and activate defense mechanisms effectively.
“These findings expand our understanding of biological processes under simulated Martian conditions and reveal how hydrated organisms respond to ionising radiation – one of the most critical challenges for survival and habitability on Mars.
“Ultimately, this research deepens our knowledge of lichen adaptation and their potential for colonising extraterrestrial environments.”
Further long-term studies investigating the impact of chronic radiation exposure on lichens have been recommended, as well as experiments assessing their survival in real Martian environments.
The study is published in IMA Fungus.
