Source: Collective Evolution
About four billion years ago, bacteria created minuscule tubes and filaments, most likely in deep-sea hydrothermal vents. A team of scientists from University College London (UCL) believe they have found the remains of the microorganisms, which means they’ve been preserved for billions of years. The scientists suggest they could even be the oldest fossils ever discovered by humans.
The microfossils, which are made of a type of rust called haematite, were found inside quartz layers of the Nuvvuagittuq Supracrustal Belt (NSB) in Quebec, Canada. If such a discovery proves to be true, it could offer insight into the origins of life on Earth.
“If these rocks do indeed turn out to be 4.28 [bn years old] then we are talking about the origins of life developing very soon after the oceans formed 4.4 bn years ago,” noted Matthew Dodd, who is the first author of the research from University College, London.
The team explains that the findings support the idea that life emerged and diversified on Earth very quickly. Dodd also noted that the discovery of the structures reveals new ways to determine if life existed elsewhere in the solar system. “If we look at similarly old rocks [from Mars] and we can’t find evidence of life, then this certainly may point to the fact that Earth may be a very special exception and life might just have arisen on Earth,” said Dodd.
The rocks are among the oldest in the world, and believed to have taken form around underwater hydrothermal vents.
“These rocks were of a period in time when we don’t know whether there was life,” said Dodd. “If we believe the long-standing hypothesis that life evolved from hydrothermal vents billions of years ago then these were the perfect rocks to look at for answering these questions.”
The researchers also note that the haematite structures may not have been formed by physical processes alone, writing that “the tubes and filaments are best explained as remains of iron-metabolising filamentous bacteria, and therefore represent the oldest life forms recognised on Earth.”
The filaments, which are up to half a milliliter in length and half the width of a human hair, come in various forms, including loose coils, branched structures, and some connected through a central knob of haematite. Dodd explained that such shapes are common to microbes that have lived near deep sea vents.
“The microfossils’ structures in themselves are almost identical, very similar, to microfossils and micro-organisms we see in similar hydrothermal vent settings today,” said Dodd.
Frances Westall, an expert on ancient fossil bacteria at the French national centre for scientific research, remains a skeptic on the findings, however. “The thing that bothers me most about these structures is the fact that they all seem to be extremely oriented. They are parallel to each other and microbes don’t grow parallel to each other,” she said.
If the study proves true, we may eventually have evidence for past life on Mars 4,000 million years ago, making the urgency to get to Mars even more credible.
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