Carbon cycle


Carbon is an essential chemical element in the constitution of biological organisms, it is a bioelement. Like water, oxygen and nitrogen, it circulates between the main layers of the Earth in a process of deep transformations known as the carbon cycle. Its importance is enunciated from the vitality that its organic chemistry transmits, to the consequences of excess gases composed of carbon in the biosphere.


What is the carbon cycle?

Carbon atoms have the ability to bond with each other and / or with other bioelements, forming an infinity of compounds essential for life. These compounds are abundant on Earth and circulate through living things and the environment in a natural and reciprocal process, known as the carbon cycle . Thus carbon passes from biological organisms to the atmosphere, from the atmosphere to plants, from plants to animals and soils, from the atmosphere to the oceans, and vice versa.

  • What is the carbon cycle?
  • features
  • Organisms that participate in the carbon cycle
  • Carbon cycle step by step
  • Profits
  • Alterations

What is the carbon cycle?

It consists of the movement of carbon through the different layers and forms of life on Earth . Carbon in its gaseous state flows in a constant and balanced way, thanks to the development of physical, chemical, geological and biological processes.


The bioelement is present in nature in different forms , in minerals such as diamond, graphite and carbon; in organic and inorganic substances, there is inorganic carbon in the water of the seas; in carbon dioxide, expelled through the respiratory tract by living beings, also a product of the decomposition of organic matter and volcanic emissions.

The carbon cycle allows the production and decomposition of the chemical element, its use and reuse. Sometimes the cycle is altered by the interference of man. It was first studied by scientists Joseph Priestley and Antoine Lavoisier.


The carbon cycle is characterized by the transformation and reciprocity of the chemical element and its compounds between the different parts of the Earth. It is dynamic.

It controls the temperature by processing the CO2 in the atmosphere and sending another part of the compound to natural or man-made reservoirs known as carbon sinks. It acts as a thermoregulator.

The binding capacity of carbon atoms multiplies the number of organic and inorganic compounds available. The cycle causes these compounds to flow naturally in living things and the environment. It is versatile.

Organisms that participate in the carbon cycle

In the cycle in which energy is produced and nutrients are exchanged, all links in the food chain participate.

Chemical interaction occurs between the environment and biological organisms , hence the description as the biogeochemical cycle. Living beings are active participants in the carbon cycle, in its natural process, and in the case of humans, also in the damage (pollution) that they generate from the search for “better” ways of survival.

Plants, consumers of CO2 and producers of oxygen, are perhaps the strongest link in the chain; they synthesize the carbohydrates on which herbivorous and carnivorous animals later feed, according to the order of the trophic chain .

Life on the planet depends on sunlight, the constituent chemical elements and the appropriate conditions for their use.

Carbon cycle step by step

The carbon cycle, although complex due to the versatility of the element and the reactions in nature, can be summarized in five basic processes:

  • Respiration : Carbon dioxide (CO2), made up of one molecule of carbon and two of oxygen, is consumed as an energy source and expelled into the air – as a by-product – through the respiration of all living beings. Both solar energy and glucose molecules that release oxygen, which in turn are made up of hydrogen, oxygen and six carbon atoms are involved in this process. In this way, the transfer of CO2 from living beings to the atmosphere takes place.
  • Photosynthesis : In the photosynthesis process, plants absorb CO2 and convert chemical energy into oxygen, which is released into the atmosphere through plant respiration, or, failing that, serves as a nutrient for herbivorous animals that ingest the plant during synthesis. Herbivores are then preyed upon by other members of the food chain. The function of chlorophyll allows the use of carbon compounds in their passage from the atmosphere to plants.
  • Decomposition : Carnivorous animals die and their bodies are eaten by other living beings, heterotrophs. Fungi, bacteria, protozoa, and other single-celled organisms feed on organic matter, breaking it down. In the process they release carbon dioxide through respiration and the generation of inorganic substances rich in carbon and other elements. These substances or compounds go to the soil and are reused by plants for the continuity of the cycle. Decomposing organisms make possible the transfer of carbon from animals to the atmosphere and soils.
  • Evaporation : Carbon molecules also travel from the atmosphere to the oceans, and vice versa, through the process of evaporation of water that occurs during the cycle of the vital liquid. There is more carbon in the sea than you might think, it is trapped on the surface by plankton, microscopic organisms suspended in the water and on which fish, crustaceans , echinoderms , whales and even sharks feed . When the crustaceans die, their crusts go to the bottom of the sea and form rocks, generally limestone, which, once out of the water, degrade and release carbon dioxide.
  • Combustion : It results in the excessive release of heat into the atmosphere, a product of the burning -in large quantities- of fossil fuels sources of carbon. Combustion occurs naturally, due to volcanic emissions and involuntary forest fires, but for at least two centuries it has been mainly caused by the interference of man and the development of industrial activities.


The concentration of high doses of carbon dioxide or carbon monoxide (the toxic presentation of the element) in the atmosphere raises the temperature. If it is not controlled and reduced, it would end up destroying the favorable conditions for life.

The main benefit of the carbon cycle is the administration of the chemical element , the balance that provides its production, use, decomposition and recycling, as well as the natural deposits ‘in which the excesses are stored’, for their later use.

Biological organisms evolve thanks to the energy and nutrients of carbon, it is an essential element in its composition, but in the wrong proportions it can be harmful.


The carbon cycle favors the natural order on Earth , however, in recent centuries it has been altered not only by natural combustion processes, but also by man’s indiscretion in the management of industries and the exploitation of rich elements or materials. in carbon, including wood, coal, oil and natural gas .

From the different forms of carbon, products that humans consume on a large scale, automobile fuels, oils, and domestic gas, among others, are obtained, therefore, the exploitation of these energy sources is also done on a large scale and at a speed difficult to assimilate naturally, contributing to the generation of so-called winter gases, responsible for overheating the earth.

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