Diverse forms of microbial life existed at least 3.75 billion years ago, study confirms

(ORDO NEWS) — In 2017, paleontologists discovered microscopic filaments and tubes between 3.75 and 4.28 billion years old, which turned out to be created by iron-loving bacteria, in rocks from the Nuvvuagittuk supracrustal belt in Quebec, Canada.

However, not all scientists agreed that these structures – dating back some 300 million years before what is commonly believed to be the first sign of ancient life – are of biological origin.

Now, after careful further analysis of the Nuvvuagittuka rocks, paleontologists have discovered a much larger and more complex structure – a stem with parallel branches on one side almost 1 cm long, as well as hundreds of distorted spheres, or ellipsoids, located next to the tubes and filaments.

While some of these structures may have arisen from random chemical reactions, the parallel-branched tree-like stem was most likely biological in origin, as no structure created through chemistry alone has been found to resemble it.

The new results suggest that the primitive Earth, perhaps as early as 300 million years after the formation of the planet, had a diverse microbial life.

“Using a wide variety of evidence, our study strongly suggests that a number of different types of bacteria existed on Earth between 3.75 and 4.28 billion years ago,” said Dr. Dominic Papineau, a paleontologist at the China University of Geosciences, London Center for Nanotechnology, Faculty of Sciences. on the Earth and the Center for Planetary Sciences, University College London and Birkbeck College London.

“This means that life could have originated as early as 300 million years after the formation of the Earth. In geological terms, this is very fast – about one revolution of the Sun around the Milky Way galaxy.”

“These findings have implications for the possibility of extraterrestrial life,” he added.

“If life arose relatively quickly, given the right conditions, it increases the likelihood of life on other planets.”

For the study, Dr Papineau and his colleagues studied rocks from the Nuvvuagittuk supracrustal belt they collected in 2008.

The Nuvvuagittuk Supracrustal Belt, once a seafloor, contains some of the oldest sedimentary rock known on Earth, thought to have been deposited near a system of hydrothermal vents.

Paleontologists cut the rock into pieces roughly paper-thin (100 microns) to closely examine tiny fossil-like structures that are made of hematite and encased in quartz.

These rock cuts, cut with a diamond-coated saw, were more than twice as thick as the previous cuts, allowing the research team to see larger hematite structures in them.

They compared the structures and composition with later fossils, as well as iron-oxidizing bacteria that live near hydrothermal vents today.

They found the modern equivalents of twisting filaments, parallel branching structures, and distorted spheres, for example, near the undersea volcano Loihi in Hawaii, and in other vent systems in the Arctic and Indian Oceans.

Using microtomography and ion beam techniques, the scientists confirmed that the hematite filaments were wavy and tortuous and also contained organic carbon—characteristics shared with modern iron-eating microbes.

In their analysis, they concluded that hematite structures could not have arisen from compression and heating of rock (metamorphism) over billions of years, noting that the structures were better preserved in finer (less metamorphic) quartz than in coarser quartz ( which has undergone more metamorphism).

The authors also studied the level of rare earth elements in fossil rocks and found that it was the same as in other samples of ancient rocks.

This confirmed that the seafloor deposits were as old as the surrounding volcanic rocks, and not younger, self-styled infiltrates, as some had suggested.

“Our unprecedented results contribute to the search for extraterrestrial life by demonstrating that a variety of co-occurring biosignatures, including microfossils, dubiofossils, abiotic diagenetic microstructures, trace element compositions, and minerals associated with expected products of diagenetically oxidized biomass, can provide a well-founded interpretation of early biological evolution.” scientists say.

“This discovery suggests that it takes only a few hundred million years for life to evolve to an organized level on a primordial habitable planet.”

“We therefore conclude that such microbial ecosystems may have existed on other planetary surfaces where liquid water interacted with volcanic rocks, and that these oldest microfossils and dubiofossils from the Nuvvuagituk Supracrustal Belt suggest that extraterrestrial life may be more common than previously thought.” “.


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