Traces of life that existed 3.4 billion years ago found on Earth
Primitive life formed on Earth at the very beginning of its existence. Scientists have discovered traces of ancient life that point to an ecosystem 3.4 billion years old.
This is stated in a study published in the scientific journal Precambrian Research. The evidence was discovered during the analysis of rocks found in South Africa.
The research was conducted by Manuel Reinhardt from the University of Göttingen in Germany and his colleagues. They studied rocks from the Buck Reef, which is part of the Barberton Greenstone Belt in South Africa. These rocks are estimated to be 3.42 billion years old. They are believed to be the remnants of shallow seas that surrounded a chain of volcanic islands.
In the layers of this rock, microscopic clots of carbonaceous matter were found, which, according to scientists, are the remains of microorganisms that lived in these seas.
Reinhardt and his colleagues focused on the carbon itself. It exists in several forms called isotopes. The main two isotopes of carbon are carbon-12 and carbon-13. The presence of the first isotope indicates a biological substance, while the second isotope indicates a non-biological one.
However, according to scientists, not all living things absorb carbon-12 equally well. This means that the ratio between these two forms can provide a key to understanding an organism's metabolism.
A significant carbon footprint was found in the material from the rocks, which corresponds to photosynthesis - the ability to use light energy to produce sugar. This is proof that billions of years ago, a huge number of photosynthetic microbes lived near the sea surface.
According to News Scientist, Reinhardt found that some rock remains had a lower carbon-12 content. He speculates that these microbes probably fed on a chemical called acetylcoenzyme A.
Other clumps had even lower levels of carbon-12, which may be an indication that the microbes in them produced methane or acetate as waste, which other microbes then fed on.
The scientist notes that it is impossible to say for sure whether all the microbes lived in the same place at the same time. He suggests that photo-synthesizing organisms could have lived near the surface of the water, while others could have lived in sediment on the seabed.
The study adds new evidence for an earlier origin of life on Earth than previously thought. The age of the Earth is known to be 4.5 billion years.