Scientists have found a meteorite-munching microbe that thrives on the metals found in extraterrestrial rocks that have crash-landed on Earth. Named Metallosphaera sedula, astrobiologists are studying this microbe and its peculiar ability to derive energy from inorganic extraterrestrial sources. Their findings are published in the journal Scientific Reports this week.
M. sedula was originally isolated from a volcanic field in Italy. It belongs to a domain of single-celled organisms known as archae, which are not related to bacteria, viruses, animals, plants, or fungi. They are chemolithotrophic, meaning they harness energy from inorganic sources through a process of oxidation.
Unlike other organisms of this ilk, M. sedula consumes inorganic compounds found in meteorites. To investigate this, researchers placed a culture of M. sedula onto sterilized chunks of NWA 1172, a multi-metallic meteorite rich in iron found 19 years ago in Algeria. They noted the colony actually grew much faster on the meteorite than on the minerals of terrestrial origin.
To ensure this wasn’t just because of the meteorite's porous structure providing more surface area, they also ran the same test with ground-up samples. Once again, the meteorite proved to be the dish of the day for M. sedula, resulting in notably faster growth and colonization.
“Meteorites-fitness seems to be more beneficial for this ancient microorganism than a diet on terrestrial mineral sources,” lead author Tetyana Milojevic, from the Department of Biophysical Chemistry at the University of Vienna in Austria, said in a statement.
The microbe's ability to efficiently chow down on meteorites could have some practical uses too. By tracking the movement of the inorganic constituents from the meteorite into the microbial cell, the team was able to track the “microbial fingerprints” left on extraterrestrial material. This could possibly be used as a tool to further understand meteorite biogeochemistry and even find evidence of extraterrestrial life elsewhere in the Solar System and beyond, especially those that have a taste for meteorites and other metals.
"Our investigations validate the ability of M. sedula to perform the biotransformation of meteorite minerals, unravel microbial fingerprints left on meteorite material, and provide the next step towards an understanding of meteorite biogeochemistry,” explained Milojevic.