explain c3 cycle with diagram
Answers
The carbon cycle
The carbon cycle is most easily studied as two interconnected subcycles:
One dealing with rapid carbon exchange among living organisms
One dealing with long-term cycling of carbon through geologic processes
Although we will look at them separately, it's important to realize these cycles are linked. For instance, the same pools of atmospheric and oceanic CO2 that are utilized by organisms are also fed and depleted by geological processes.
As a brief overview, carbon exists in the air largely as carbon dioxide—
CO2\text{CO}_2
CO
2
C, O, start subscript, 2, end subscript
—gas, which dissolves in water and reacts with water molecules to produce bicarbonate—
HCO3−\text{HCO}_3^-
HCO
3
−
H, C, O, start subscript, 3, end subscript, start superscript, minus, end superscript
. Photosynthesis by land plants, bacteria, and algae converts carbon dioxide or bicarbonate into organic molecules. Organic molecules made by photosynthesizers are passed through food chains, and cellular respiration converts the organic carbon back into carbon dioxide gas.
Longterm storage of organic carbon occurs when matter from living organisms is buried deep underground or sinks to the bottom of the ocean and forms sedimentary rock. Volcanic activity and, more recently, human burning of fossil fuels bring this stored carbon back into the carbon cycle. Although the formation of fossil fuels happens on a slow, geologic timescale, human release of the carbon they contain—as CO2 is on a very fast timescale.
The carbon cycle
The carbon cycle is most easily studied as two interconnected subcycles:
One dealing with rapid carbon exchange among living organisms
One dealing with long-term cycling of carbon through geologic processes
Although we will look at them separately, it's important to realize these cycles are linked. For instance, the same pools of atmospheric and oceanic
CO2\text{CO}_2
CO
2
C, O, start subscript, 2, end subscript
that are utilized by organisms are also fed and depleted by geological processes.
As a brief overview, carbon exists in the air largely as carbon dioxide—
CO2\text{CO}_2
CO
2
C, O, start subscript, 2, end subscript
—gas, which dissolves in water and reacts with water molecules to produce bicarbonate—
HCO3−\text{HCO}_3^-
HCO
3
−
H, C, O, start subscript, 3, end subscript, start superscript, minus, end superscript
. Photosynthesis by land plants, bacteria, and algae converts carbon dioxide or bicarbonate into organic molecules. Organic molecules made by photosynthesizers are passed through food chains, and cellular respiration converts the organic carbon back into carbon dioxide gas.
Longterm storage of organic carbon occurs when matter from living organisms is buried deep underground or sinks to the bottom of the ocean and forms sedimentary rock. Volcanic activity and, more recently, human burning of fossil fuels bring this stored carbon back into the carbon cycle. Although the formation of fossil fuels happens on a slow, geologic timescale, human release of the carbon they contain—as CO2 is on a very fast timescale.