According to a recent study lead by UCL academics, diverse microbial life existed on Earth at least 3.75 billion years ago, challenging the conventional idea of when life began.
The research team looked at a fist-sized rock from Quebec, Canada, that was believed to be between 3.75 and 4.28 billion years old for the study, which was published in Science Advances.
The team discovered small filaments, knobs, and tubes in the rock that looked to be formed by bacteria in an earlier Nature paper.
However, not all scientists agreed that these structures were biological in origin, despite the fact that they were 300 million years older than what is usually recognized as the first trace of ancient life.
After further investigation of the rock, the researchers uncovered a considerably larger and more complicated structure – a roughly centimeter-long stem with parallel branches on one side – as well as hundreds of misshapen spheres, or ellipsoids, beside the tubes and filaments.
While some of the structures could have been generated by chance chemical reactions, the “tree-like” stem with parallel branches was most likely biological in origin, according to the researchers, because no structure like it has been found created solely through chemistry.
The researchers also show how the bacteria obtained energy in several ways. They discovered mineralized chemical by-products in the rock that are consistent with ancient bacteria surviving on Iron, Sulphur, and perhaps Carbon Dioxide and light via a non-oxygen photosynthesis.
According to the researchers, these new findings show that microbial life may have existed on primordial Earth as early as 300 million years after the planet formed.
“Using many different lines of evidence, our study strongly suggests a number of different types of bacteria existed on Earth between 3.75 and 4.28 billion years ago,” said lead author Dr. Dominic Papineau (UCL Earth Sciences, UCL London Centre for Nanotechnology, Centre for Planetary Sciences, and China University of Geosciences).
“This suggests that life could have started as soon as 300 million years after the Earth was formed.” This is fast in geological standards — roughly one rotation of the Sun around the galaxy.”
“These discoveries have implications for the existence of alien life.” Given the correct conditions, life can emerge relatively quickly, increasing the chances that life exists on distant planets.”
The researchers also looked at the levels of rare earth elements in the fossil-rich rock, which were found to be similar to those found in other ancient rock specimens.
This proved that the seafloor deposits were the same age as the surrounding volcanic rocks, not younger imposter infiltrations as some had speculated.
Prior to this finding, the world’s oldest fossils were discovered in Western Australia and dated at 3.46 billion years old, though some scientists questioned their designation as fossils, claiming they were not biological in nature.
To read our blog on “In-lab simulations of the Earth’s magnetosphere,” click here.
