Geologists from Trinity College Dublin are readjusting our evolutionary timeline. According to Science Daily, recent findings have concluded that the very first oxygen-producing life forms appeared on Earth 3 billion years ago, pushing the timeline 60 million years earlier. The same life forms were responsible for allowing our planet to flourish in oxygen, encouraging more complex life to evolve millions of years later.
In a joint study between Trinity College Dublin and the Presidency University in Kolkata, India, scientists discovered rocks that were chemically weathered in the presence of oxygen. Upon further examination using uranium-lead isotopes, which is commonly used to determine the age of million-year-old rock formations, it was discovered that the oxygen-related weathering occurred 3.02 billion years ago, indicating that oxygen-producing life capable of photosynthesis. like plants. was present during the time. According to researchers, the weathering and the resulting soil formation would have only occurred in an environment with high amounts of oxygen, which could have only been produced by organisms which can convert sunlight and CO2.
The study has been published on one of the world’s most prestigious scientific journals, Geology. Quentin Crowley, a Trinity College Dublin professor who co-authored the study, said that the findings are a great contribution to our current knowledge of evolution.
“This is a very exciting finding, which helps to fill a gap in our knowledge about the evolution of the early Earth. This paleosol from India is telling us that there was a short-lived pulse of atmospheric oxygenation and this occurred considerably earlier than previously envisaged.”
The research conclusions adjust the current scientific knowledge on the presence of oxygen during the early years of Earth. According to earlier models, oxygen did not significantly rise in levels in the atmosphere until 2.4 billion years ago, in the period they called the “Great Oxidation Event”. Once considered one of the most vital points of our evolutionary history, the event might face some adjustments because of more recent findings, which effectively places a significant oxidation event millions of years before the more recognized one.
Although microorganisms definitely existed before 3 billion years ago, they were unlikely able to produce oxygen. Professor Crowley says that the weathering of the rocks and soil they studied provided a significant addition of knowledge to the early stages of life on Earth.
“The chemical changes which occur during this weathering tell us something about the composition of the atmosphere at that time. Very few of these ‘paleosols’ have been documented from a period of Earth’s history prior to 2.5 billion years ago. The one we worked on is at least 3.02 billion years old, and it shows chemical evidence that weathering took place in an atmosphere with elevated O2 levels.”
Before 3.4 billion years ago, there were little to no oxygen present in the atmosphere of our early planet. By around 3 billion years ago, oxygen produced by photosynthesis-capable organisms may have primarily pushed for the rise in oxygen levels in the atmosphere.
[Image from Takashi Hososhima/Flickr/