According to recent research, meteorites are an unappreciated food source for a particular metal-loving microorganism. The finding could reveal a whole new chemistry that made life on Earth easier – or even how life ever came here.
The beautifully named Metallosphaera sedula is able to consume and process "extraterrestrial material," as the authors describe in their new study published this week in Scientific Reports
The study, led by astrobiologist Tetyana Milojevic of the University of Vienna, suggests that meteorites are a food source for certain chemolitrophic archaea a group of bacteria-like microbes that extract their energy from inorganic substances , what they do through the miraculous powers of oxidation. In addition, this discovery could shed new light on the conditions under which early life on Earth could arise and develop, with meteorites playing a surprisingly important role. Even more speculative, the finding could support the panspermia hypothesis: the idea that life came from space to earth.
Metallosphaera sedula is so named because of its metallophilic or metal-loving properties, but the new research suggests a possible renaming due to their preference for meteorites. In fact, this microbe can gain energy sources faster from foreign rocks than from simple ancient terrestrial minerals.
"We conducted this study to detect microbial fingerprints – metal-containing microfossils – on rocky extraterrestrial material," Milojevic said in an email to Gizmodo. "This should be helpful in detecting biosignatures for finding life elsewhere in the universe. If it ever came to life on another planet, similar microbial fingerprints could be preserved in the geological records.
This type of research could provide astrobiologists with "small clues" that they should seek in search of alien life. And indeed, "this was the main motivation of the study," Milojevic said.
The team investigated how this particular organism interacted with NWA 1172, a stony meteorite found in northwest Africa, and the ways in which it alters this extraterrestrial rock. Using various spectroscopy techniques and an electron microscope, the researchers documented the fingerprints of M. sedula .
As the investigation revealed, M. sedula cells can consume useful meteoric material much faster than terrestrial minerals. These alien rocks seem to offer a better energy choice for the microbes, resulting in healthier, fitter cells. NWA 1172 happens to be a very multimetallic meteorite that contains about 30 different metals and according to the study provides a wealth of trace metals that accelerate the metabolic activity and growth of the microorganism .
"Sulfide minerals – the & # 39; terrestrial food & # 39; of M. sedula – only a few of them [energy sources]"said Milojevic. "Iron from NWA 1172 is used as an energy source to satisfy M. sedula requires bioenergetic energy as the microbes breathe out due to iron oxidation [breathe].
The wide range of other metal elements from NWA 1172 could be used for other metabolic processes such as the acceleration of vital chemical processes. Reactions in cells, explained Milojevic. And because the meteorite is very porous, it could promote M. sedula increased growth rate.
It is important to mention that archaea was one of the first organisms gracing this good earth, therefore it is possible that M. The ancestors of sedula sourced scarce or useful nutrients Meteorites, of which there was plenty at that time. Future research should further explore this possibility and investigate how extraterrestrial materials could have enriched the Earth's environment .
"Iron meteorites that are rich in iron-nickel-phosphide could have brought more phosphorus to the earth than they naturally occur and facilitate the development of life," said Milojevic.
Another fascinating possibility raised by this research is the problem of panspermia – the idea that microbial life did not arise spontaneously on the primordial earth but from there other planets come from meteorites. This is still an unproven theory but still an interesting one since scientists have not fully clarified the origin of life on our planet.
As an astrobiologist, Milojevic is fully aware of this theory, which is also known as lithopanspermia, but her new research adds a seductive twist to this possibility. Perhaps an ancestor of M. sedula, or a similar microorganism was brought on meteorites on earth. In such a scenario, these alien microbes of course would have clung to metal-rich rocks, but when their home planet was hit by a large celestial object, the rocks – and microbes – were thrown into the interstellar space.
And indeed Milojevic would like to explore this possibility.
"To support the lithopanspermia hypothesis, we plan to test the survival of M. sedula under simulated and real space conditions, "Milojevic told Gizmodo, adding that limited funding could prevent such research. "Hopefully M. sedula grown on various mineral springs will undertake a space journey. A project to expose these microbes to space will not be a cheap scientific research initiative – money does not grow on trees. "
Fair point. Hopefully, Milojevic and her colleagues will continue this investigation. This possibility is too fascinating to ignore.