Life on Earth may have originated 4.28 billion years ago, earlier than known

Have you ever seen life that feeds on iron, sulfur, carbon dioxide, and infrared light? Recently, a new study by scientists from China University of Geosciences (Wuhan) and a number of research institutions shows that such microbial life activities already existed on Earth as early as 4.28 billion years ago. Compared to the previously confirmed 3.45 billion years, it brings the origin of life on Earth at least 300 million years ahead of schedule. The study challenges traditional understanding of the time of origin of life on Earth, and the results were recently published in Science Advances.

The research team analyzed a fist-sized rock from the Canadian province of Quebec, and previous studies have used isotopic dating methods to determine its age to be at least 3.75 billion years old and as old as 4.28 billion years ago. After a more comprehensive and in-depth analysis of the rocks, the researchers discovered a larger and more complex “branch” structure — a nearly 1-centimeter-long main stem and parallel tubular branches growing unilaterally, as well as a large number of symbiotic ellipsoids.

Since no non-biological pure chemical processes have been found to produce similar structures, this “branch”-like structure is most likely a microbial community formed by ancient bacteria. At the same time, the researchers found that some mineralized biochemical reaction byproducts were retained in the samples, suggesting that these different types of ancient microorganisms may be based on iron, sulfur, carbon dioxide and infrared radiation energy on the seafloor, performing non-oxygen-producing photosynthesis.

First author Dominique Papino, a postdoctoral fellow at the University of Geotechnical Sciences, said, “Between 3.75 billion and 4.28 billion years ago, there were already a variety of microbial life on Earth. This means that life may have appeared only three hundred million years after the formation of the Earth, and from a geological point of view, life appeared very rapidly, about the same time as the time it took for the sun to rotate around the Milky Way. ”

“These findings have important implications for the possibility of the emergence of extraterrestrial life.” If life could emerge quickly on Earth under the right external environmental conditions, it would increase the likelihood of life on other planets. She Zhenbing, a co-author of the study and a professor at the University of Geotechnical Sciences, said. Zhenbing She, postdoc matt Dodd, and Dominique Papino, a leading talent of “geo-university scholars”, participated in the research.

One of the main pieces of evidence of the existence of this ancient life comes from the spectral analysis of samples, which are ‘fingerprints’ that reveal the chemical information of life in minerals. “Using spectral imaging analysis, we were able to see the spatial distribution of various compounds in the sample. If compounds of carbon and phosphorus are found in minerals, it suggests that these minerals may be the products of degradation by early organisms.” She Zhenbing said.

Samples from the Nova Vajituk dermatoc rock belt in Quebec were collected by Papino during a 2008 field expedition. The area contains the oldest known sedimentary rocks on Earth, and near the seafloor hydrothermal system, iron-rich seawater produced by magma heating rises through seafloor fissures, forming these iron-bearing rocks after deposition. The researchers cut the rock into sections of about 100 microns to observe the tiny fossil structures with light microscopes, Raman spectrometers and electron microscopes.


Newly discovered NSB hematite mineralized dendrite fossil with local enlargement Courtesy of the author

In addition, the research team used a microCT, focused ion beam-scanning electron microscopy system to perform layer-by-layer high-resolution imaging of the sample interior, and 3D digital reconstruction with a supercomputer. From the above analysis, the researchers confirmed that the NSB hematite filaments have the characteristics of modern iron metabolism microorganisms, especially similar to iron bacteria in modern seafloor hydrothermal vent systems. (Source: China Science Daily, Feng Lifei, Cheng Xiaolong, Xiao Zhan, Pang Weihong)

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