Researchers Propose Meltwater Beneath Martian Ice Could Support Microbial Life.

The white material in this Martian gully, captured by NASA’s Mars Reconnaissance Orbiter in 2009, is believed to be dusty water ice, which scientists consider a promising site for searching for microbial life on Mars today.

These holes on Alaska’s Matanuska Glacier, formed by cryoconite melting into the ice, create small pockets of water. Scientists believe similar pockets could form within dusty water ice on Mars.

While no definitive evidence of life on Mars has been found, a new NASA study suggests that microbes could potentially thrive beneath the planet’s icy surface. The research indicates that sunlight penetrating water ice might enable photosynthesis in shallow pools of meltwater below the surface. On Earth, similar conditions in ice support diverse life forms, including algae and cyanobacteria.

Lead author Aditya Khuller of NASA’s Jet Propulsion Laboratory states, “If we’re trying to find life anywhere in the universe today, Martian ice exposures are probably one of the most accessible places we should be looking.” The study, published in *Nature Communications Earth & Environment*, focuses on water ice formed from ancient snow mixed with dust during past Martian ice ages.

The presence of dark dust in the ice plays a crucial role, as it absorbs more sunlight than the surrounding ice, potentially warming it enough to melt and create subsurface pools of water. This process could occur up to several feet below the surface, offering a viable habitat for microbial life.

The white edges of the gullies in Mars’ Terra Sirenum are thought to be dusty water ice, where scientists believe meltwater could form beneath the surface, potentially enabling photosynthesis. This enhanced-color image shows blue hues that would not be visible to the human eye.

Mars scientists are divided on whether ice can melt on the Martian surface due to the planet’s thin atmosphere, which typically causes water ice to sublimate rather than melt. However, beneath a dusty snowpack or glacier, the conditions may differ significantly.

On Earth, similar dust in ice creates cryoconite holes—small cavities formed as dust absorbs sunlight and melts surrounding ice. This process can sustain ecosystems for simple lifeforms. Phil Christensen from Arizona State University highlights that ice can melt from the inside out, allowing sunlight to penetrate and warm it like a greenhouse.

Christensen has studied Martian ice for decades, leading research using the THEMIS camera on NASA’s Mars Odyssey orbiter. Previous modeling suggested that liquid water could form within Mars’ dusty snowpacks, laying the groundwork for current research on potential photosynthesis on Mars.

Recent findings indicate that dusty ice may allow light penetration sufficient for photosynthesis as deep as 9 feet below the surface, with upper ice layers preventing evaporation and protecting against harmful radiation—a crucial factor given Mars’ lack of a magnetic field.

The authors suggest that subsurface water ice is likely found in Mars’ tropics, between 30 and 60 degrees latitude. Future studies aim to recreate Martian dusty ice in the lab and identify specific locations on Mars for potential human and robotic exploration focused on shallow meltwater.