The carbon cycle is the natural process by which carbon moves through the Earth's ecosystems, atmosphere, oceans, and geosphere. It plays a vital role in regulating Earth's climate and supporting life. Here’s a breakdown of its major components:
1. Atmospheric CO₂
Carbon dioxide (CO₂) exists in the atmosphere and is a central part of the carbon cycle.
Plants, oceans, and certain geological processes absorb and release it.
2. Photosynthesis
Plants, algae, and some bacteria absorb CO₂ from the air and, using sunlight, convert it into glucose and oxygen.
This is how carbon enters the biosphere.
Equation:
CO₂ + H₂O + sunlight → C₆H₁₂O₆ (glucose) + O₂
3. Respiration
Animals, plants, and microbes breathe out CO₂ as they break down sugars for energy.
This process returns carbon to the atmosphere.
4. Decomposition
When organisms die, decomposers (like bacteria and fungi) break down their bodies, releasing carbon back into the soil or atmosphere.
5. Oceanic Carbon Exchange
Oceans absorb CO₂ from the atmosphere.
Marine organisms use it to form calcium carbonate shells.
Some CO₂ returns to the atmosphere via oceanic respiration and warming waters.
6. Sedimentation and Fossil Fuels
Dead organisms, especially in marine environments, may become buried and over millions of years form fossil fuels (coal, oil, gas).
Carbon is stored long-term underground as sediments or fossil fuels.
7. Combustion
Burning fossil fuels releases stored carbon rapidly into the atmosphere as CO₂.
This human-driven activity significantly amplifies atmospheric CO₂ levels.
8. Volcanic Activity
Volcanic eruptions also release carbon from Earth’s mantle back into the atmosphere.
Summary Diagram Flow:
Atmosphere ⇄ Plants ⇄ Animals ⇄ Soil/Ocean ⇄ Fossil Fuels/Sediments ⇄ Atmosphere.
The balance of this cycle has been disrupted by human activities, especially fossil fuel combustion, leading to climate change due to increased greenhouse gases.
~ NGA Geography
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