Newly discovered bacteria fossils from Quebec, Canada now possibly hold the record for the world's oldest fossil.
These bacteria, only a few micrometers in size, were discovered in rock formations. The best estimation is that these bacteria were extremophiles living in the hot vents of earth's oceans during the planet's early life. The bacteria resembled small tube structures. They fed on iron, similar to how modern iron-oxidizing bacteria thrive around hydrothermal vents.
[Image Source: Dominic Papineau et al.]
Not only does the discovery serve as an exciting archaeological find, it also shows that organisms lived 4.2 billion years ago. That's several hundred million years prior to previous estimates.
Researchers with the University College London made the discovery. They also hope these fossils can help identify similarly marked fossils on Mars. If so, Mars and Earth would have one more connection of sustaining life.
"Early Mars and early Earth are very similar places, so we may expect to find life on both planets at this time,” said doctoral student Matthew Dodd, the lead author of the study, in an interview with the Telegraph:
"We know that life managed to get a foothold and evolve rapidly on Earth. So if we have life evolving in hydrothermal vent systems maybe even 4.2 billion years ago when both planets had liquid water on their surface, then we would expect both planets to develop early life."
Fossils from Western Australia previously held the record for the oldest fossil. The microfossils dated to 3.4 billion years ago. This led scientists to guess that life started 3.7 billion years ago.
Nuvvuagittuq Area [Image Source: NASA via Wikipedia]
However, the study comes with its fair share of skeptics. Geologist Martin J. Van Kranendonk with University of New South Wales told the New York Times they were "dubiofossils." Dubiofossils appear to be fossils but no one can prove they started as something living.
"They haven't proved these structures are of biological origin," he said. "The rocks in which they have been found are strongly recrystalized."
However, Dodd and his peers seem unphased by the criticisms. Professor Franco Pirajno, a co-author from the University of Western Australia, said he expected such responses:
"I'm not surprised at the criticisms. I did expect something like that. But you have to put the whole picture together.
"No.1, [the research shows] the structures were formed in a submarine environment; two, there are thermal springs; and three, we have these tubular features. What else could they be?"
Dodd also noted that these findings could just prove an earthly exception when compared with any Martian samples:
"If we do future sample returns from Mars and look at similarly old rocks and we don’t find evidence of life then this certainly may point to the fact that Earth might have been a very special exception, and life may just have arisen on Earth."
The full article was published in Nature journal.
If anything, this find reignites discussion into life on Mars. It could also be loosely applied to NASA's recent discovery of seven exoplanets in the Trappist-1 system. Three of those planets orbit in the 'habitable' zone, NASA said. Were teams able to travel to Trappist-1, would they find similar bacterial fossils on the Trappist-1 equivalent of Mars?
For a quick recap on how fossils are formed, you can check out this simple animation below: