Scientists have unveiled findings indicating that exposed ice on Mars could create conditions favorable for photosynthesis, raising the possibility that microbial life could exist despite the planet’s harsh environment and intense ultraviolet radiation.
The research highlights that photosynthetic organisms may be uniquely suited for survival in specific icy regions near the planet’s mid-latitudes.
Photosynthetic life on Mars
According to the new study, photosynthesis, which relies on sunlight to produce food, would typically be impossible on the Martian surface due to its lack of an ozone layer, exposing it to significantly higher levels of harmful ultraviolet (UV) radiation.
However, just beneath the surface ice, a few centimeters could provide enough shielding against radiation, allowing photosynthetic organisms to thrive.
Researchers are now proposing that these so-called “radiatively habitable zones” could be prime locations to search for evidence of microbial life. If small amounts of liquid water are present, simple organisms may be able to survive in these areas.
Study findings and implications
A research team, including Aditya Khuller, Stephen Warren, Philip Christensen, and Gary Clow, conducted a radiative transfer analysis of icy regions on Mars. Their models indicate that mid-latitude regions contain relatively clean ice with low dust concentrations, enhancing the potential for sunlight to penetrate and support photosynthesis.
“The results presented here indicate that radiatively habitable zones exist within exposed mid-latitude ice on Mars at depths ranging from a few centimeters for ice with 0.01–0.1 per cent dust, and up to a few meters within cleaner ice,” the team stated in their paper. The presence of liquid water, along with these conditions, could create icy habitats conducive to microbial life forms that rely on photosynthesis.
Learning from Earth’s microbial life
The study draws parallels to Earth, where microbial life has thrived in extreme conditions, including glacial environments. Notably, cyanobacteria have been found living beneath translucent ice, capturing sunlight filtered through the ice to survive.
The research suggests that Mars’ mid-latitude regions could offer similar environments where such life forms could exist, scavenging nutrients from Martian dust while being shielded from harmful UV rays.
“Our analysis shows that despite higher surface ultraviolet radiation levels on Mars than on Earth, it is possible for terrestrial photosynthetic organisms to find locations within exposed ice on Mars with favorable solar radiative conditions,” the authors wrote.
Future missions to Mars
The findings underscore that the icy slopes of Mars’ mid-latitudes, which are expected to melt for a portion of the Martian year, may represent accessible locations for future searches for life.
“If exposures of dusty mid-latitude Martian ice are melting below the surface for a fraction of the year as predicted by numerical models, then, like on Earth, microbes such as cyanobacteria could scavenge nutrients from the Martian dust mixed in with the ice,” the authors explained.
Future missions to Mars, including robotic probes and potentially crewed missions, could focus on these promising ice exposures, paving the way for significant advancements in our understanding of habitability on Mars and the possibility of extraterrestrial life.
