Great Oxygenation Event

Definition

The Great Oxygenation Event (GOE) was a period when Earth's atmosphere and shallow ocean experienced a rise in oxygen levels due to photosynthetic microbes. This event significantly altered the planet's environment and allowed aerobic life forms to thrive.

5 Must Know Facts For Your Next Test

1. The GOE occurred around 2.4 to 2.1 billion years ago.
2. Photosynthetic cyanobacteria were primarily responsible for producing oxygen during the GOE.
3. The increase in atmospheric oxygen led to the formation of the ozone layer, which protected life from harmful UV radiation.
4. The GOE caused a mass extinction of anaerobic organisms that could not survive in an oxygen-rich environment.
5. Oxygen levels fluctuated after the GOE before stabilizing at higher concentrations.

Review Questions

• What microbial activity contributed to the Great Oxygenation Event?
• How did the Great Oxygenation Event impact anaerobic organisms?
• What environmental change resulted from increased oxygen levels after the GOE?

Related terms

Cyanobacteria:

Photosynthetic bacteria that played a crucial role in producing oxygen during the GOE.

Anaerobic Organisms: Microorganisms that do not require oxygen for growth and may even die in its presence.

Ozone Layer: A layer of ozone molecules in Earth's stratosphere that absorbs most of the Sun's harmful ultraviolet radiation.