The Great Oxidation Event: How Cyanobacteria Changed Life
The Great Oxidation Event marked a significant transformation in Earth's atmosphere due to the emergence of cyanobacteria. These microorganisms developed the ability to perform photosynthesis, releasing oxygen as a by-product and gradually altering the atmospheric composition. This shift not only impacted climate but also facilitated the evolution of aerobic life forms.
- ▪Cyanobacteria evolved around 2.7 billion years ago and were capable of photosynthesis, producing oxygen.
- ▪The Great Oxidation Event occurred between 2.4 and 2.1 billion years ago, leading to significant changes in Earth's atmosphere.
- ▪The rise of oxygen levels contributed to one of the earliest ice ages by displacing methane, a greenhouse gas.
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| Original publisher | ASM.org |
| Canonical URL | https://asm.org/articles/2022/february/the-great-oxidation-event-how-cyanobacteria-change |
| Publication time | Wed, 29 Apr 2026 08:19:02 +0000 |
| Retrieval time | 2026-04-29T08:31:52.291Z |
| Last seen | 2026-04-29T08:31:52.291Z |
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The Great Oxidation Event: How Cyanobacteria Changed Life Kartik Aiyer, Ph.D. Published: Feb. 18, 2022 Share This Save This Illustration of Cyanobacteria, Prochlorococcus spp. Source: Derek Tan/flickr.com. We are so acclimatized to the presence of oxygen on our planet Earth, that we take it for granted. However, oxygen was absent from the earth’s atmosphere for close to half of its lifespan. When the earth was formed around 4.5 billion years ago, it had vastly different conditions. At that time, the earth had a reducing atmosphere, consisting of carbon dioxide, methane and water vapor, as opposed to the present-day atmosphere that consists primarily of nitrogen and oxygen.
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