If oxygen is the mainstay of all lifeforms, carbon is the essence of life. A major portion of the structure of any life form is composed of carbon and its compounds. Carbohydrates, which is the main source of energy for all lifeforms, contains carbon as its main constituent. Carbon atoms are everywhere; in plants, animals, oceans, air, rock, soil, etc., and it doesn't stay in one place.
Various natural and man-invoked activities ensure that the carbon atoms are always on the move. But this circulation of carbon is not random. It follows a particular pattern, a periodic cycle that is known as the carbon cycle. In the sections given below, we will see a simple diagram and explanation.
What is a Carbon Cycle?
It is a cycle involving biological, geological, and chemical processes in which carbon atoms are exchanged between the Earth's biosphere, pedosphere, geosphere, hydrosphere, and the atmosphere. Carbon cycle is one of the most important cycles of the Earth and symbolizes the recycling of this abundant element throughout the biosphere as well as in all of its organisms.
It is usually considered that there are five major reservoirs of carbon on the planet, which are interlinked by flow of exchanges. These reservoirs are:
- The atmosphere
- The terrestrial biosphere, which includes freshwater sources and other organic material like soil carbon.
- The oceans―contain dissolved carbon in inorganic as well as organic, living and non-living, and marine flora and fauna.
- The sediments, which includes fossil fuels.
- The planet's interior has carbon in the Earth's mantle and crust. It is vented to the atmosphere or hydrosphere by volcanic eruptions and geothermal activities.
Simple Carbon Cycle Steps and Diagram
Let us see the diagram below in a symbolic form first that illustrates the flow of carbon in various processes amongst the various layers discussed above.
Here is the exact flow of events, as carbon flows from one layer to another as shown in the diagram above.
- In the process of photosynthesis, atmospheric carbon is absorbed by plants.
- This carbon is transferred form plants to the animals feeding on them, and further moves up the food chain.
- Respiration, digestion, and metabolism of plants and animals result in some transfer of carbon back to the atmosphere.
- Some carbon also moves to the lithosphere when these living organisms die or when wood and leaves decay or when animals excrete. Some of these living beings buried millions of years ago have been converted to fossil fuels.
- Mining and burning of fossil fuels cause this carbon to move from the lithosphere to the atmosphere.
- Some of this atmospheric carbon gets dissolved in the oceans and thus, completes the cycle.
Below is another general flow chart of a carbon cycle representing the movement of carbon in various layers. In this one, we can clearly understand the complete steps of the carbon cycle and one can easily figure out that the total amount of carbon remains fixed. There is no creation or destruction of carbon in this process and only involves the movement of this element around a complete cycle in compound form.
Hope, you have thoroughly understood the diagram and process of carbon cycle. In these times of greenhouse effect concerns, maintaining the balance in the carbon cycle becomes very vital.