Universe Today
According to a new NASA-funded study that appeared in Astrobiology, the next missions to Mars should be on the lookout for rocks that look like "fettuccine". The reason for this, according to the research team, is that the formation of these types of rocks is controlled by a form of ancient and hardy bacteria here on Earth that are able to thrive in conditions similar to what Mars experiences today.
This bacteria is known as Sulfurihydrogenibium yellowstonense, which belongs to a lineage that evolved over 2.35 billion years ago, a time that coincides with the earlier portion of the Great Oxygenation Event. Using sulfur and carbon dioxide as energy sources, this hardy bacteria thrives in heat and extremely low oxygen environments and can withstand exposure to ultraviolet light.
In hot springs, the microbe assembles itself into strands and promotes the crystallization of calcium carbonate rock (aka. travertine), which is what gives it its "pasta-like" appearance. This behavior makes it relatively easy to detect when conducting geological surveys and would make it easy to identify when searching for signs of life on other planets.
Sufuri Fieldshot at Yellowstone National Park. Credit: Bruce Fouke.
Bruce Fouke, a professor of geology and an affiliate professor with the Carl R. Woese Institute for Genomic Biology (IGB) at the University of Illinois, was also the lead researcher on the study. “It has an unusual name, Sulfurihydrogenibium yellowstonense," he said in an interview with the Illinois News Bureau. "We just call it ‘Sulfuri... Taken together, these traits make it a prime candidate for colonizing Mars and other planets."
The unique-shape and structure of these strands are the result of the environment this bacteria evolved to survive in. Given that they inhabit fast-flowing water, the Sulfuri bacteria form into chains in order to prevent from being washed away. This way, they are able to remain fixed to rock formations and absorb nutrients from the hot springs. As Fouke explained:
To analyze the bacteria, the researchers collecting samples from Mammoth Hot Springs in Yellowstone National Park, using sterilized pasta forks (of all things!) The team then studies the microbial genomes to evaluate which genes were being actively transplanted into proteins, which allowed them to discern the organism's metabolic needs.
Close up of Sufuri bacteria and the strands they form at Yellowstone National Park. Photo by Bruce Fouke.
The team also examined the bacteria's rock-building capabilities and found that proteins on the bacterial surface dramatically increase the rate at which calcium carbonate crystallizes in and around the strands. In fact, they determined that these proteins cause crystallization at a rate that is one billion times faster than in any other natural environment on the planet.
As Fouke indicated, this type of bacteria and the resulting rock formations are something Mars rovers should be on the lookout for, as they would be an easily-discernible biosignature:
Further Reading: Illinois News Bureau, Astrobiology
