Researchers at the University of Vienna have successfully cultivated extremophilic microbes on a fragment of a Martian meteorite, demonstrating the potential for life under ancient Martian conditions.
As preparations advance for a mission to return samples collected by NASA's Perseverance rover, it's worth noting that Martian rocks are already available on Earth. These specimens were ejected by ancient meteorite impacts, journeyed through the solar system, and eventually reached our planet.
In a groundbreaking experiment, scientists used a piece of the renowned 'Black Beauty' meteorite—a composite of Martian crust dating back 4.4 billion years—to cultivate microbes.
The objective was to test whether life forms could survive and proliferate in conditions resembling ancient Mars.
The team hypothesized that any past Martian life would resemble Earth's extremophiles, which thrive in extremely harsh environments.
Ancient Mars had a thick, carbon dioxide-rich atmosphere. On Earth, chemolithotrophs—organisms that fix CO2 and derive energy from inorganic minerals—are ideal candidates. The researchers selected Metallosphaera sedula, an archaeon adapted to hot, acidic volcanic springs.
The microbes were inoculated onto the Martian mineral and placed in a bioreactor with controlled heat, air, and CO2.
Microscopic analysis revealed robust growth, with the microbes clearly adapting to the Martian substrate. Chemical analyses showed they transformed the rock to build new cells, producing biomineral deposits rich in iron, manganese, and aluminum phosphates.
“We observed intracellular crystalline deposits of complex iron and manganese oxides, along with mixed manganese silicates—unique features not seen when growing these microbes on terrestrial minerals,” the researchers reported.
These findings offer critical insights for detecting ancient life on Mars. As M. sedula's biosignatures are now characterized, they can guide analysis of Perseverance's samples for similar extraterrestrial traces.
