2.5 Billion-Year-Old Fossils Of Bacteria Uncovered, Show Early Life Forms Existed On Earth Without Oxygen
A new research presents a 2.5 billion-year-old fossilized bacteria found in two different locations in the Northern Cape Province of South Africa. This discovery indicates that some early life forms on Earth existed without any oxygen.
The findings of the discovery were printed in the December issue of the journal Geology of the Geological Society of America. It was led by Andrew Czaja, UC assistant professor of geology and his colleagues Nicolas Beukes from the University of Johannesburg and Jeffrey Osterhout from UC's department of geology.
Andrew Czaja, UC assistant professor of geology, said that these are the oldest reported fossil sulfur bacteria to date. He further said that the discovery is helping them reveal a diversity of life and ecosystems that existed just prior to the Great Oxidation Event, a time of major atmospheric evolution.
The first half of the 4.5 billion-year-old of the Earth's life is a significant time for the development and evolution of early bacteria. During that time, the oxygen levels in the atmosphere were less than one-thousandth of 1 percent of what they are today, and the evidence about life forms and how they survived were sparse, according to Phys.Org.
In the discovery, Professor Czaja described the sulfur oxidizing bacteria as exceptionally large, spherical-shaped, smooth-walled microscopic structures that are much larger than most modern bacteria. On the other hand, they are like some modern single-celled organisms that live in deep-water sulfur-rich ocean settings today, wherein even now there are almost no traces of oxygen, according to Czaja.
Sulfur-oxidizing bacteria prior to the Great Oxidation Event DOI: 10.1130/G38150.1
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The researchers found the samples of abundant bacteria in deep waters of the ocean in geologic time known as the Neoarchean Eon dated 2.8 to 2.5 billion years ago. Czaja said that these fossils represent the oldest known organisms that lived in a very dark, deep-water environment. He added that the bacteria existed 2 billion years before plants and trees, which evolved about 450 million years ago.
Scientists postulated that there were things living in deep water in the mud that did not need sunlight or oxygen. On the other hand, they have no direct evidence yet, according to Deccan Herald.