Scientists have long thought the prevalence of oxygen in the Earth’s atmosphere began around 2.3 billion years ago with what is now known as The Great Oxidation Event. A recent Live Science article discusses some new research which suggests that oxygen could have been present much earlier than that widely accepted time period.
Scientists in South Africa studying ancient rock samples have discovered high levels of chromium which they view as evidence of a reaction between oxygen and minerals found in Earth’s rocks. Stunningly, these samples date back to around 600 million years earlier than The Great Oxidation Event.
So what’s the big deal? The findings suggest that photosynthetic organisms were present on earth much earlier than previously thought. The team that made the discovery is convinced that the levels oxygen that were present on Earth are far too high to be the product of natural chemical reactions in the atmosphere. Most scientists agree that the jump in oxygen levels at the time of The Great Oxidation Event were caused by the development of cyanobacteria, which photosynthesize energy from the sun, producing oxygen. The fact that oxygen levels were higher than once thought before the Great Oxidation Event most likely means that some type of organism was performing photosynthesis much earlier in Earth’s lifespan than previously believed.
Not only do the findings further our understanding of the development of life on our planet, they also change our perception of how long a complex process like photosynthesis takes to develop. While purely speculative, Sean Crowe of the University of Vancouver believes that the findings could have implications on other planets. If oxygen producing life forms can develop relatively quickly, it follows that there could be more planets in the universe which have oxygen in the atmosphere and oxygen breathing life forms. In short, this new research means there could be a larger number of planets which are habitable to humans than we once believed.
How and when any of this research can be applied remains to be seen, but it certainly is an exciting development.