The Great Oxygenation Event (GOE), also called the oxygen catastrophe, the Great Oxidation, or the oxygen crisis, was an important environmental event that occurred around 2.4 billion years ago. It was when free oxygen began to accumulate in Earth’s atmosphere. The GOE was a pivotal moment in the history of life on Earth; it set the stage for the rise of aerobic organisms and eventually led to the development of complex life forms.
The event is thought to have been triggered by a dramatic increase in photosynthetic activity by cyanobacteria, which are bacteria that use sunlight to convert water and carbon dioxide into organic matter (food). This increased photosynthesis caused a build-up of oxygen in the atmosphere, which had previously been almost entirely devoid of oxygen. The high levels of atmospheric oxygen created conditions that were unfavorable for many existing life forms, but conducive to new types of organisms that could tolerate or even thrive in an oxygen-rich environment.
Over time, these new organisms came to dominate Earth’s biosphere, and the GOE is now considered one of the most important drivers of evolution on our planet. While there is still much we don’t know about this pivotal event in Earth’s history, ongoing research is providing us with new insights into how it unfolded and what its lasting effects have been on both our planet and its inhabitants.