How did oxygen form on our planet?
Oxygen was created on our planet through a process known as the Great Oxidation Event , about 25 to 23 billion years ago. This process was primarily driven by the activity of cyanobacteria , which played a crucial role in the production of oxygen.
Role of cyanobacteria:
Cyanobacteria, also known as “blue-green algae”, are microscopic organisms capable of photosynthesis . In this process, they use sunlight, carbon dioxide (CO₂) and water (H₂O) to produce sugars as an energy source. An important by-product of photosynthesis is oxygen (O₂).
Before the arrival of cyanobacteria and photosynthesis, the Earth's atmosphere was deoxygenated. The early Earth consisted primarily of gases such as methane, nitrogen, and carbon dioxide. Cyanobacteria changed this landscape dramatically by releasing oxygen into the oceans over millions of years.
Great Oxidation Event:
In the beginning, the oxygen produced was absorbed by dissolved minerals in the oceans, such as iron. This led to the formation of iron oxide (rust), which precipitated on the ocean floor and so-called banded iron formations (layered iron formations) created. It wasn't until the iron supply was depleted that oxygen began to accumulate in the atmosphere.
