Oxygen in the air

Although oxygen in the atmosphere now seems to be the fundamental basis of life, its initial appearance was more of a catastrophe for the young Earth. The environmental impact of this oxygen catastrophe was global and had three significant consequences:

  1. The rising oxygen levels in the oceans likely led to the extinction of a large portion of the organisms that inhabited the Earth at that time. Oxygen was lethal to these organisms and thus responsible for a mass extinction event.
  2. Atmospheric methane (a potent greenhouse gas) was oxidized to carbon dioxide (a weaker greenhouse gas) and water, which triggered a prolonged and complete ice age on Earth.
  3. Free oxygen caused dramatic changes in the chemical interactions between the Earth's solid materials, the atmosphere, and the oceans, among other factors. This led to a significant increase in the diversity of minerals found on Earth. It is estimated that more than 2,500 of the approximately 4,500 known minerals were formed as a result.

However, the increased oxygen levels also opened new avenues for the evolution of living organisms. The availability of free oxygen in the atmosphere was a breakthrough in the evolution of energy metabolism, greatly increasing the supply of free energy for living beings.

 

Go to Editor View