We explain what the carbon cycle is and what this biogeochemical circuit consists of. Also, the importance it has for life.
What is the carbon cycle?
A carbon cycle is known as a biogeochemical circuit exchange of matter (specifically carbon-containing compounds) between the biosphere, the pedosphere, the geosphere, the hydrosphere and the atmosphere of the Earth. It was discovered by the European scientists Joseph Priestley and Antoine Lavoisier, and together with the Water and nitrogen, is part of the cycles that allow the sustainability of life on our planet.
Since carbon (C) is a key element for the life and for most of the known organic compounds, it is involved in numerous substances of organic (and inorganic) origin, in a continuous transmission that allows its reuse and recycling, holding the levels of said element in a global balance.
Carbon in the world exists in different forms and areas: in the mineral carbon reserves under the ground, in the form of inorganic carbon dissolved in the water of the sea, at carbon dioxide in the atmosphere (product of volcanic emissions or the respiration of living beings), in the decomposition processes of organic matter in swamps and other lands.
Broadly speaking, carbon stocks are: atmospheric carbon, the content in the body of living beings in the biosphere (including marine and aquatic beings), carbon dissolved in seawater and deposited to the bottom of the oceans, and the mineral deposits of the Earth crust, including deposits of Petroleum and others hydrocarbons.
The exchange routes between these deposits are:
- The processes of fermentation and decomposition. The large deposits of organic material are rich in carbon and organisms that live from the decomposition and transformation of said matter, obtaining energy in exchange and releasing gases into the atmosphere such as methane (CH4) or CO2.
- The breathing and the photosynthesis. Together with other biotic metabolic processes, these processes release and capture carbon dioxide from the atmosphere, respectively, as a by-product or input of their biochemical pathways. Carbon in CO2 is absorbed by the plants and is released along with water steam during the animal respiration.
- The ocean gas exchange. The water in the oceans evaporates by the action of the sun, as established by the water cycle. In this process, the water vapor produced and released into the atmosphere also promotes the exchange of gases between the atmosphere and the ocean, which allows the carbon to dissolve in the water, where it is fixed by photosynthetic plankton.
- Sedimentation processes. Both on land and in the sea, the excess carbon in decomposing organic matter, which is not captured and processed by decomposing life forms, will pile up and settle at the bottom of the oceans or in the various layers of the earth's crust, where it forms fossils, hydrocarbon deposits or reactive sediments.
- Natural combustion or by the hand of humanity. Human industrial processes and spontaneous forest fires must be taken into account in the carbon cycle, since they are responsible for the annual increase in carbon in the atmosphere, in the form of greenhouse gases. This is due to burning fossil fuels, to the release of organic gases produced by human industry, or to eventual natural volcanic emissions.
All these processes take place at the same time and constitute a delicate balance cycle, which allows carbon to circulate in different environments and as part of substances of a very different nature. An interruption of this circuit means the impoverishment of many vital areas and, possibly, the end of life as we know it.