Mars is a pretty inhospitable planet. It's cold, it's dry, and it gets lots of ultraviolet light on its surface. We don’t know if there’s life there – or if there was in the past. Two new independent studies show that we can’t discount the possibility, and that we need to pay attention to what we send to the Red Planet.
Life From Earth Could Deal With Martian Conditions
The first work is published in Frontiers in Microbiology. Researchers working on the study found that life forms from Earth could temporarily survive on Mars. Bacteria and fungi were sent to the stratosphere in a balloon, where they were kept in Martian atmosphere conditions and exposed to UV radiation from the Sun.
Not all the microorganisms survived the trip, but some of them did. In particular, spores from the black mold Aspergillus niger and the bacterium Salinisphaera shabanensis managed to stave off complete destruction. This should inform us how to protect Mars from microbes that inadvertently might hitch a ride on our crafts, as some of them might survive on the Red Planet.
"We successfully tested a new way of exposing bacteria and fungi to Mars-like conditions by using a scientific balloon to fly our experimental equipment up to Earth's stratosphere," Marta Filipa Cortesão, joint first author of this study from the German Aerospace Center, Cologne, Germany said in a statement. "Some microbes, in particular spores from the black mold fungus, were able to survive the trip, even when exposed to very high UV radiation."
"With crewed long-term missions to Mars, we need to know how human-associated microorganisms would survive on the Red Planet, as some may pose a health risk to astronauts," says joint first author Katharina Siems, also based at the German Aerospace Center. "In addition, some microbes could be invaluable for space exploration. They could help us produce food and material supplies independently from Earth, which will be crucial when far away from home."
Microbes Like Mars Soil Too
The second study, published in Nature Communications Earth and Environment, is equally exciting, as the researchers grew microbes on soils sourced from a Martian meteorite. The team used meteorite Northwest Africa (NWA) 7034, a piece of Mars about 4.5 billion years old. A few grams of it were crushed and exposed to chemolithotrophs, rock-eating microorganisms. The question they were trying to answer was if such organisms existed on Mars, what traces might they have left behind?
"We can assume that life forms similar to chemolithotrophs existed there in the early years of the red planet," astrobiologist Tetyana Milojevic, the head of Space Biochemistry group at the University of Vienna said in a statement.
The team found that these chemolithotrophs constructed mineral capsules made of iron, manganese, and aluminum phosphates. These were unique to the old Martian soil, and unlike what is done by these microbes on Earth – or even in lab experiments on non-martian carbon-rich meteorites.
It could be possible in the future to look for these mineral structures directly on Mars.