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Full Version: Chemical evidence of ancient life detected in 3.3-billion-year-old rocks
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https://www.eurekalert.org/news-releases/1105611

INTRO: Pairing cutting-edge chemistry with artificial intelligence, a multidisciplinary team of scientists found fresh chemical evidence of Earth’s earliest life—concealed in 3.3-billion-year-old rocks—and molecular evidence that oxygen-producing photosynthesis was occurring over 800 million years earlier than previously documented.

In a groundbreaking study published in the Proceedings of the National Academy of Sciences, a team of Carnegie researchers including Robert Hazen, Michael Wong, and Anirudh Prabhu, along with scientists from several partner universities and institutions, analyzed more than 400 samples, including ancient sediments, fossils, modern plants and animals, and even meteorites, to see if life’s signature still exists in rocks long after the original biomolecules are gone.

Using high-tech chemical analysis to break down both organic and inorganic materials, Michael L. Wong, Anirudh Prabhu, and colleagues trained A.I. to recognize chemical ‘fingerprints’ left behind by life—signals that can still be detected even after billions of years of geological wear and tear.

The results prove the possibility of distinguishing materials of biological origin—like microbes, plants and animals—from materials of non-living origin—like meteoritic or synthetic carbon) with over 90 percent accuracy.

Impressively, these methods teased out chemical patterns unique to biology in rocks as old as 3.3 billion years. Previously, no such traces had been found in rocks older than about 1.7 billion years. The results, therefore, roughly double the window of time in which organic molecules preserved in rocks can reveal useful information about the physiology and evolutionary relationships of their original organisms.

The work also provides molecular evidence that oxygen-producing photosynthesis—the process used by plants, algae and many microorganisms to harness sunlight—was at work at least 2.5 billion years ago. This finding extends the chemical record of photosynthesis preserved in carbon molecules by over 800 million years.

Besides helping find evidence of Earth’s earliest life, this work advances a potential way to identify traces of life beyond our planet... (MORE - details, no ads)