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Processes of the Carbon Cycle - Coggle Diagram
Processes of the Carbon Cycle
Precipitation
Atmospheric CO2 is dissolved in rainwater to form weak carbonic acid.
This is a natural process: however, due to rising CO2 in the atmosphere, acidity in rainfall has increased, leading to an increase in acidity on surface ocean water with a harmful effect on marine life.
Photosynthesis
CO2 is taken from the atmosphere for plants to use in photosynthesis.
Weathering
Weathering is the in - situ breakdown of rocks at or near the earths surface.
Chemical weathering: rainwater
Rainwater dissolves limestone and chalk in a process known as carbonation.
Carbonation releases carbon from limestone to streams, rivers, oceans and the atmosphere.
This can be most effective under a cover of soil because the rain water can absorb CO2 from the soil, which increases its concentration.
Chemical weathering transfers 0.3 billion tonnes of carbon to the atmosphere and oceans each year so it is quite significant.
Physical weathering
Freeze thaw weathering may break rocks down into smaller pieces. This increases its surface area and vunerability to chemical weathering
Biological weathering: chelation
Chelation is where rainwater mixed with dead and decaying organic material in the soil forms humid acids which attack rock minerals
Respiration
The process in which carbohydrates are converted to CO2 and water.
Respiration causes plants and animals to absorb oxygen and release CO2 back into the atmosphere.
This and photosynthesis are the two most important processes in the fast carbon cycle. (in and out of the atmosphere)
Decomposition
Bacteria and fungi break down dead organic matter.
This extracts energy and releases CO2 into the atmosphere as they respire.
The rate of decomposition is dependent on climatic conditions. Warm, humid conditions cause higher rates of decomposition (such as the rainforest). Rates of decomposition are slower in colder environments (such as the tundra).
Combustion
Natural fuel
Wildfires caused by lightning strikes
Human activities
Deliberate burning of forest fires to create farmland
Burning of fossil fuels to create energy
This alone transfers 10 GT of carbon dioxide a year from geological stores to the atmosphere, oceans and biosphere.
When material burns in the presence of oxygen. This releases CO2 into the atmosphere.
Carbon sequestration in the oceans
Physical pump
CO2 enters the surface ocean naturally from diffusion.