Leonard David's INSIDE OUTER SPACE

Credit: NASA

There’s been a research boost to locate life that may have found a comfy niche on the Red Planet.

The potential for photosynthesis on Mars within snow and ice is the subject of a just-released paper appearing in the journal Nature Communications Earth & Environment.

As for implications for life on Mars, the analysis indicates 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 research team explains.

The white material seen within this Martian gully is believed to be dusty water ice. Scientists believe this kind of ice could be an excellent place to look for microbial life on Mars today.
Image credit: NASA/JPL-Caltech/University of Arizona

Present-day habitats

These potential present-day habitats are centimeters to meters below the surface, the research team observes, “and could be the most easily accessible locations to find extant life on Mars via future robotic and human missions.”

These findings are led by Aditya Khuller, currently at the Jet Propulsion Laboratory, California Institute of Technology.

Khuller is a Postdoctoral Researcher at JPL. His research interests include studying planetary ices, surface processes and atmospheres using a combination of numerical modeling, remote sensing data and geological mapping.

These holes, captured on Alaska’s Matanuska Glacier in 2012, are formed by cryoconite — dust particles that melt into the ice over time, eventually forming small pockets of water below the glacier’s surface. Scientists believe similar pockets of water may exist on Mars.
Image credit: Kimberly Casey CC BY-NC-SA 4.0

Variety of organisms

If indeed present and accounted for, what kind of life might be detected?

“A variety of organisms are found in these shallow subsurface habitats within terrestrial ice, such as cyanobacteria, chlorophytes, fungi, diatoms, and heterotrophic bacteria,” Khuller and colleagues report.

Usually, the most dominant organisms in these habitats are cyanobacteria.

“Cyanobacteria have developed appropriate mechanisms to deal with a wide range of temperatures, nutrient deficiency, UV radiation, and desiccation. These communities can persist even if temperatures are above freezing for only a few days per year,” the research paper explains.

Computer modeling

The research work uses computer modeling to suggest that dusty ice lets in enough light for photosynthesis to occur as deep as 10 feet (3 meters) below the surface.

Zones where levels of DNA-damaging irradiance are safe and there is enough photosynthetically active radiation (PAR) for photosynthesis to occur are shown as the green areas, as a function of (a) dust content, (b) ice radius, (c) latitude, and (d) solar zenith angle.
Image credit: Khuller, et al.

In this situation the upper layers of ice prevents the shallow subsurface pools of water from evaporating and protects those watery pools from harmful radiation.

As for where on Mars the water ice would form these subsurface pools, future exploration would be in the midlatitudes — between the latitudes of 30 degrees and 60 degrees — in both the northern and southern hemispheres of the Red Planet.

In the zone

“This latest paper examines the propagation of solar radiation into the ice, showing that just below the surface there is a zone that is safe from ultraviolet but still gets enough visible light to support photosynthesis,” said co-author Steve Warren, professor emeritus of Earth and space sciences at the University of Washington (UW) in Seattle.

“But of course photosynthetic organisms won’t survive unless the ice in that zone can melt, at least occasionally,” Warren states in a UW statement.

Credit: NASA/Pat Rawlings

Next step

In November, Khuller will join UW’s Applied Physics Laboratory as a senior research scientist. He plans to continue working to find out where liquid water is likely to exist and persist on Mars.

The next step, Khuller explains, will be to recreate some of Mars’ dusty ice in a lab setting.

Meanwhile, Khuller and research partners are starting to map out the most likely spots on Mars to look for shallow meltwater, pinpointing them as possible scientific targets for future robotic and human expeditions.

Co-authors of the just-issued Mars work, along with Khuller and Warren, are Philip Christensen of the School of Earth and Space Exploration at Arizona State University in Tempe and Gary Clow of the Institute of Arctic and Alpine Research at the University of Colorado/Boulder.

To access the paper – “Potential for photosynthesis on Mars within snow and ice” – go to:

https://www.nature.com/articles/s43247-024-01730-y

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