What is the carbon cycle
The carbon cycle is trajectory that carbon takes through the different spheres of the Earth. This cycle goes through chemical, physical, geological and biological processes, and is part of the biogeochemical cycles essential for life.
In this sense, the carbon cycle has a global reach, since it distributes the element in all parts of the Earth. Depending on its location, carbon interacts in different ways with other elements and living beings. During the course of the cycle, this element is recycled, forming part of gaseous, solid or liquid chemical compounds.
To be more concrete, carbon changes state and is transferred between four reservoirs on Earth:
Atmospherewhere it is found in the form of carbon dioxide (CO2) when it joins with oxygen, both in gaseous form.
Biospherein terrestrial and marine ecosystems, both in living beings and in decomposing matter.
Oceans, rivers and lakes, which are part of the hydrosphere. There is carbon dissolved in water, in marine organisms and beings in the process of decomposition.
Earth crust, which are part of the geosphere or lithosphere. Carbon is found in minerals, sediments, fossils and fossil fuels.
In the next section, we explain the stages of the carbon cycle in more detail.
Stages of the carbon cycle
The carbon cycle is divided into the biological, or fast, carbon cycle and the geological, or slow, carbon cycle. Both cycles are interrelated, since they pass through the same natural reservoirs.
Biological or rapid carbon cycle
The steps that carbon follows in the biological cycle are:
Carbon fixation through photosynthesis, carried out by both plants and photosynthetic bacteria. Carbon sinks, that is, natural deposits with a lot of vegetation that absorb CO2, are vital to carry out this part of the cycle.
Release of some carbon through respiration, whether in animals and humans, or by plants during plant respiration, at night. In both cases, the carbon is released again in the form of CO2.
Release of part of the carbon via decomposition of living beings. When living beings die, both on land and in the sea, part of the carbon contained in them returns to the atmosphere or is assimilated by other living beings.
Geological or slow carbon cycle
The path that carbon follows throughout the geological cycle is:
Carbon fixation through photosynthesis. This step is the same as the biological cycle, but part of the fixed carbon follows a different path.
Carbon mineralization and sedimentation. When organisms on land and sea die, part of the carbon contained in them reacts with other elements and compounds. Because of this, carbon mineralizes and sediments, also forming fossils and fossil fuels. On the other hand, a small percentage of the carbon in the atmosphere settles in the soil or dissolves in water.
Release of carbon into the atmosphere. Through a slow process, carbon continues to react with different compounds and elements until it is released again into the atmosphere, in the form of gas.
CO2 and methane (CH4) emission due to mining, factory activity and vehicle transportation. Human action is accelerating a cycle that would naturally take centuries to complete. Exploiting minerals and fossil fuels releases large amounts of carbon into the atmosphere.
Importance of the carbon cycle
The carbon cycle It is essential for the nutrition and survival of living beings. Carbon is a key energy source for the formation of proteins, lipids, carbohydrates and DNA. Therefore, without this element, life would not exist.
Another factor to take into account is the renewal of matter on Earth and elaboration of materials. Carbon reacts with various elements, forming gaseous, solid or liquid molecules. Human beings have used these molecules and the properties of carbon to make rubber, gum, carbonated drinks, jewelry or as a catalyst for reactions, among other uses.
He carbon dioxide It is the gas that helps create the greenhouse effect, retaining heat in the atmosphere and preventing the Earth from being a frozen planet. In other words, carbon is part of a compound that helps regulate the earth’s climate.
In biogeochemical cycles, the carbon cycle influences others, especially that of oxygen. Atmospheric carbon is mainly in the form of carbon dioxide (CO2). With photosynthesis, in addition to fixing carbon, oxygen is released into the atmosphere, a crucial step for the flow of its own cycle.
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