A recent study by NASA proposes that microbial life could exist beneath the frozen surface of Mars, supported by meltwater pools formed within the planet's ice. Utilizing computer modeling, researchers demonstrated that sunlight can penetrate water ice, potentially facilitating photosynthesis in shallow meltwater.
The lead author, Aditya Khuller from NASA's Jet Propulsion Laboratory, emphasized that Martian ice exposures are promising sites for astrobiological studies. Mars features two types of ice: water ice and frozen carbon dioxide. The study, published in Nature Communications Earth & Environment, focused on water ice, which has accumulated over millions of years from snow and dust.
Dust particles within the ice may obscure light in deeper layers but play a crucial role in warming the ice. The dark dust absorbs sunlight, leading to melting at depths of several feet below the surface. While there is debate among scientists regarding the melting of ice on Mars due to its thin atmosphere, the study suggests that subsurface conditions differ significantly from surface conditions.
On Earth, similar processes occur where cryoconite holes form, allowing ecosystems to thrive in meltwater pockets. Co-author Phil Christensen, who has studied Martian ice for decades, noted that the melting process can occur from the inside out, creating a greenhouse effect.
This study indicates that photosynthesis could take place as deep as 9 feet (3 meters) beneath the Martian surface, with protective upper ice layers preventing evaporation and shielding against radiation. The authors point out that the most favorable locations for these subsurface pools are in Mars' tropics, between 30 and 60 degrees latitude.
Future research aims to recreate Martian dusty ice in laboratory conditions to further investigate its properties. Scientists are also identifying potential sites on Mars for future missions targeting these shallow meltwater locations.