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What is Oxygen Cycle?

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Last updated date: 24th Jul 2024
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Process of Oxygen Cycle

We breathe in oxygen. Oxygen is an essential component of our life on Earth. Mostly oxygen is used for breathing. It is the most common component of the human body. It contributes to around 65% of the total human body weight. Most of this is in the form of water. 

Here, we are going to learn about the oxygen cycle diagram, the simple oxygen cycle, and more about it. The oxygen cycle is the circulation of oxygen in the atmosphere. The oxygen cycle explains how free oxygen is available and how it is used by different organisms. In the Oxygen Cycle or Simple oxygen cycle, carbon plays an important role which is interlinked to oxygen.

Oxygen Cycle Diagram

The Oxygen Cycle

The Oxygen Cycle 

What is the Oxygen Cycle?  

Oxygen is present in many forms in the atmosphere. Oxygen can be present in free form or dissolved in water. It is utilized by organisms in different ways. It is needed for the process of respiration in plants and animals. Animals inhale oxygen and exhale carbon dioxide in the air. While plants inhale carbon dioxide and exhale oxygen during the day time and at night plants take in oxygen and give out carbon dioxide.

Hence, the oxygen cycle transfers oxygen from one form to the other. In the oxygen cycle, there is the circulation of oxygen in nature. The oxygen cycle helps in the maintenance and balance of oxygen in nature. The atmosphere, lithosphere, and biosphere are involved in this cycle.

Molecular Formula of Oxygen

Molecular Formula of Oxygen

Oxygen Cycle Steps 

  • Step 1: In the first step plants are included. Plants give out oxygen during the process of photosynthesis.

  • Step 2: Animals and other aerobic organisms take in oxygen to respire.

  • Step 3: These living beings release carbon dioxide into the atmosphere during the process of respiration. This carbon dioxide is again used by plants for photosynthesis to produce oxygen.

All these three steps complete the process of the oxygen cycle.

Oxygen Utilisation

Oxygen is utilised in the following ways.

  • Respiration: The process of inhalation of oxygen and exhalation of carbon dioxide is known as respiration. Oxygen is used by all organisms for respiration.

  • Decomposition: Decomposition in the oxygen cycle is an important process in which one compound is broken down into two or simpler compounds using oxidation. 

  • Combustion: Combustion is the rapid oxidation of a material in oxygen. Combustion is exothermic, which means heat energy is released during the combustion reaction.

  • Rusting: Rusting is the oxidation of the metal or one metal and the reduction of another. The reaction usually occurs because one type of metal is exposed to air. 

Importance of Oxygen Cycle

The oxygen cycle is an important process in Earth's atmosphere. It is a cycle of reactions involving the oxidation of carbon dioxide, the reduction of nitrous oxide, and the release of water vapour. This process effectively creates carbon dioxide and water vapour for plants to use as food for photosynthesis, which allows them to create their food sources. When this happens, it means that there is less carbon dioxide in the atmosphere and it will begin to significantly decrease radiation levels as well. Oxygen is necessary for the process of combustion. If oxygen will not be there we cannot burn fire. Without fire, we can not cook food. Hence the process of the oxygen cycle is very important. Oxygen cylinders are provided to patients who have breathing problems.

Significance of Oxygen Cycle

The significance of the oxygen cycle is as follows:

  • The importance of the oxygen cycle is that without it animals and plants would die because they need oxygen to live! 

  • Without this cycle there would be no life on Earth - humans included!  

  • It also benefits the environment, making it a huge benefit for us to contribute to this system. 

  • The Oxygen cycle also helps in reducing air pollution, deforestation clearing land for farmland etc.


Now, we know What is Oxygen cycle. The oxygen cycle represents the circulation of oxygen from one organism to the other and its utilization in different forms. The oxygen cycle involves 3 steps, in which plants, animals, and other aerobic organisms. In breathing, decomposition, combustion, and rusting, oxygen are essential. Here, we have also discussed the process of the oxygen cycle and its importance. Oxygen is produced during the process of photosynthesis. Oxygen turns food into energy. 

FAQs on What is Oxygen Cycle?

1. How is oxygen created?

One of the processes by which oxygen is released into the atmosphere is photosynthesis. Photosynthesis is a process used by green plants in which the green plants transform carbon dioxide and water into glucose and oxygen with the use of sunlight and chlorophyll. Oxygen is released into the atmosphere.

2. How is oxygen produced by plants?

Oxygen is produced by Photosynthesis in plants, which is a process wherein green plants use chlorophyll and sunlight to produce glucose and oxygen.

3. Mention the name of the oxygen reservoir.

The oxygen reservoir is as follows: 

  • The lithosphere (the Earth's crust), 

  • The Hydrosphere

  • The biosphere (plants and animals), and 

  • The atmosphere (air).