What is Oxygen Cycle? | Types, Definition, Structure, Function & Facts

What is Oxygen Cycle?

Oxygen is an essential element for life on Earth. It is the most common element of the human body. It makes up about 65% of the human body mass. Mostly in the form of water (H2O). Oxygen also makes up about 30% of the Earth and 20% of the atmosphere.

The Oxygen Cycle

Oxygen is constantly being used and produced by various processes on planet Earth. All these processes together form the oxygen cycle. The oxygen cycle is interconnected with the carbon cycle.

In the simple oxygen cycle example below, you can see how oxygen is used and recirculated by plants and animals. Plants are the main producers of oxygen in the atmosphere through photosynthesis. Here, plants use sunlight and carbon dioxide to generate energy and release oxygen. Giraffes inhale oxygen and exhale carbon dioxide. The plant can then use this carbon dioxide and the cycle is complete.

Processes That Use Oxygen

Breathing – The scientific name of the breath is respiration. All animals and plants consume oxygen when they breathe. They inhale oxygen and exhale carbon dioxide.

Decomposing – When plants and animals die, they decompose. This process consumes oxygen and releases carbon dioxide.

Rusting – This is also known as oxidation. When things rust, they consume oxygen.

Combustion – There are three things needed for fire: oxygen, fuel, and heat. Without oxygen, you cannot make fire. When things burn, they consume oxygen and replace it with carbon dioxide.

Processes That Produce Oxygen

Plants – Plants make most of the oxygen we breathe through a process called photosynthesis. In this process, plants use carbon dioxide, sunlight, and water to create energy. In the process, they also produce oxygen, which they release into the air.

Sunlight – Oxygen is produced when sunlight reacts with water vapor in the atmosphere.

Fun Facts

Although fish breathe underwater, they still breathe oxygen. Their gills extract oxygen from the water.