The oxygen cycle is fundamental for life on our planet, however without living beings its release would not happen.
The oxygen cycle consists of the circulation of this element between its reservoirs. This cycle is closely related to other cycles. In the carbon cycle, for example, two fundamental processes for the oxygen cycle also take place: photosynthesis and respiration.
The carbon dioxide present in the atmosphere is used by photosynthetic organisms for the production of sugars and oxygen gas. Oxygen is often available thanks to the activities of living beings, the photosynthesis process being considered the main responsible. It is believed that cyanobacteria, thanks to photosynthesis, were responsible for the appearance of large amounts of oxygen in the planet’s primitive atmosphere.
While the process of photosynthesis releases oxygen into the atmosphere, cellular respiration consumes it. In the process of cellular respiration, oxygen gas is used in the degradation of glucose, which will result in the formation of carbon dioxide and water. In this process, energy is released.
Oxygen is also used in the stratosphere, where part of it is transformed into ozone. The ozone layer protects living beings against ultraviolet rays emitted by the sun. This layer is becoming thinner, especially in the regions of the Poles, thanks especially to substances called chlorofluorocarbons.
Oxygen is also consumed in combustion, where it is combined with a fuel, releasing water and carbon dioxide. And another part of it can combine with metals present in the soil, forming oxides.