Carbon cycle

The carbon cycle is the process by which the carbon is exchanged between the various components of the Earth, including the atmosphere, oceans, Earth's biosphere, and soil. This cycle is essential for the maintenance of life on Earth and for the regulation of the planet's climate. The set of possible paths of a carbon atom is called the carbon cycle.

The main phases of the carbon cycle are:
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1. Photosynthesis: plants, algae and some bacteria use sunlight to convert carbon dioxide and water into glucose and oxygen through the process of photosynthesis. This process allows carbon to be stored in plant biomass;
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2. Breathing: living organisms with the activity of respiration release carbon dioxide into the atmosphere;
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3. Decomposition: when organisms die, they are decomposed by bacteria, fungi and other organisms that release CO₂ into the atmosphere or by storing carbon in the soil;
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4. Sedimentation and fossilization: part of the carbon of dead organisms can be buried in soil or marine sediments, where, over millions of years, it can be transformed into fossil fuels (coal, oil, natural gas);
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5. Combustion: the burning of fossil fuels, biomass and other organic materials releases CO₂ into the atmosphere. This includes human use of fossil fuels for energy, transport and industries;
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6. Gas exchange with the oceans: oceans absorb CO₂ from the atmosphere through diffusion. Carbon can be used by algae and marine plants for photosynthesis, turning into nutrients, or it can react with water to form calcium carbonate (limestone), which is then deposited in the ocean floor. The accumulation of limestone and other organic materials can, over millions of years, fossilize and become fossil fuels, thus returning to the slow carbon cycle;
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7. Ocean circulation: carbon can be transported by ocean currents, where it can be stored for long periods before being released back into the atmosphere;
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8. Volcanism and geothermal activities: volcanic eruptions and other geothermal activities release CO₂ from the Earth's interior into the atmosphere.
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These steps maintain an essential balance, with balanced carbon exchanges between atmosphere, land, sea and subsoil. For example, the amount of carbon dioxide released into the atmosphere through the respiration and decomposition of terrestrial animals is the same as that absorbed by plants during photosynthesis. Thus, carbon constantly circulates in stable quantities between the various components of the planet, a crucial balance for supporting life on Earth.

The carbon cycle is essential for regulating global temperature and maintaining ecological balance. However, human activities, in particular the Combustion of fossil fuels And the deforestation, they have altered the natural carbon cycle, increasing the concentration of CO₂ in the atmosphere and contributing to the climate change. We can take as an example to explain the consequences of altering the carbon cycle two phenomena: theGreenhouse effect And theocean acidification.

THEincrease in CO₂ emissions in the atmosphere it amplifies the greenhouse effect, raising the average global temperature and causing serious environmental disasters. In addition, the absorption of greater amounts of carbon dioxide by the oceans makes the water more acidic, with negative effects on the marine ecosystem, including coral bleaching.