Researchers think meltwater beneath Martian ice could support microbial life.
Mars scientists are divided about whether ice can actually melt when exposed to the Martian surface.
That’s due to the planet’s thin, dry atmosphere, where water ice is believed to sublimate — turn directly into gas — the way dry ice does on Earth.
But the atmospheric effects that make melting difficult on the Martian surface wouldn’t apply below the surface of a dusty snowpack or glacier.
Khuller next hopes to re-create some of Mars’ dusty ice in a lab to study it up close.
Scientists believe that microbial life may be supported by meltwater beneath Martian ice.
Although there has never been concrete proof of life on Mars, a recent NASA study suggests that microbes might be able to survive there under frozen water.
The researchers’ computer modeling demonstrates that photosynthesis could take place in shallow meltwater pools beneath the surface of water ice when there is sufficient sunlight to pass through it. Comparable water pools that form inside ice on Earth have been discovered to be brimming with life, including microscopic cyanobacteria, fungi, and algae that get their energy from photosynthesis.
The paper’s lead author, Aditya Khuller of NASA’s Jet Propulsion Laboratory in Southern California, stated, “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.”.
Frozen water and frozen carbon dioxide are the two types of ice found on Mars. In their study, which was published in Nature Communications Earth and Environment, Khuller and associates examined water ice, a significant amount of which was created by snow and dust that fell to the surface during a sequence of Martian ice ages that occurred in the previous million years. Since then, the old snow has turned into ice that is still .ted with dust grains.
Dust particles are important in explaining how subsurface water pools could form within ice when exposed to sunlight. Dark dust absorbs more sunlight than surrounding ice, which could cause the ice to warm up and melt down to a few feet below the surface. However, dust particles may also obscure light in deeper layers of the ice.
Regarding whether ice can truly melt when it comes into contact with the Martian surface, scientists are divided. This is because it is thought that water ice sublimates—that is, turns immediately into gas—in the planet’s thin, dry atmosphere, much like dry ice does on Earth. Subsurface to a dusty snowpack or glacier, however, the atmospheric effects that make melting challenging on the Martian surface would not hold true.
Rich Microcosms.
Cryoconite holes are tiny holes that form in ice on Earth when dust particles carried by the wind settle there, absorb solar radiation, and melt deeper into the ice each summer. This phenomenon is known as cryoconite dust. As these dust particles move away from the Sun’s rays, they eventually cease to sink, but not before producing enough heat to surround them with a pocket of meltwater. For simple lifeforms, the pockets can support a healthy ecosystem.
The melting of ice from within is a common occurrence on Earth, according to co-author Phil Christensen of Arizona State University in Tempe. Instead of melting from the top down, dense snow and ice can melt from the inside out by allowing sunlight to enter and warming it like a greenhouse. “.
Christensen has spent decades studying the ice on Mars. On NASA’s 2001 Mars Odyssey orbiter, he oversees the operation of THEMIS (Thermal Emission Imaging System), a heat-sensitive camera. Using modeling, Christensen and Gary Clow of the University of Colorado Boulder previously showed how liquid water could form inside dusty snowpack on the Red Planet. In turn, those efforts served as a basis for a recent paper that examined the possibility of photosynthesis on Mars.
Co-authors Christensen and Khuller suggested in a 2021 paper that many Martian gullies form by erosion brought on by the ice melting to form liquid water. The paper described the discovery of dusty water ice exposed within gullies on Mars.
According to a recent study, photosynthesis can take place as deep as 9 feet (3 meters) below the surface when there is enough light penetration through dusty ice. In this scenario, the upper layers of ice shield the shallow subsurface water pools from radiation damage and stop them from evaporating. That is significant because, in contrast to Earth, Mars does not have a magnetic field that would shield it from space-based radioactive cosmic ray particles and the Sun.
The water ice that would most likely form subsurface pools on Mars would be found in the tropics, in both the northern and southern hemispheres, between 30 and 60 degrees latitude.
In order to conduct in-depth research on Mars, Khuller intends to replicate some of the planet’s dusty ice in a laboratory. In the interim, he and other scientists are starting to map out the most likely places on Mars to search for shallow meltwater; these sites may serve as scientific targets for future robotic and human missions.
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