Carbon Cycle

Where is carbon stored?

- Atmosphere

- Sedimentary rocks

- Soil

- Vegetation

- Dissolved in the ocean

Photosynthesis

- This process removed carbon from the atmosphere

- CO2 is converted into small carbon containing organic molecules by photosynthesis in plants, and other photosynthetic organisms

- This carbon is then used in the production of macromolecules such as carbs, proteins, and lipids

Respiration

Respiration puts CO2 into the atmosphere, in the opposite direction to photosynthesis

CO2 is released in the Link Reaction and the Krebs Cycle of aerobic respiration

Anaerobic respiration also releases CO2 into the atmosphere, via fermentation by yeast, moulds and bacteria

Feeding

Carbon is passed from autotroph to heterotroph during feeding

Carbon is also passed from primary consumer to secondary consumer

Biomass transfer always includes the transfer of carbon, the main element in biomass

Decay & Decomposition

Dead plants and animals are fed upon by detritivores and decayed by saprophytes

Releasing carbon into the surroundings

Supplying carbon to the detritivores

Supplying carbon to the saprophytes

Waste matter such as faeces and urine is used by decaying saprobionts

Such processes can release CO2 back into the air

What happens if dead organic matter accumulates in areas where decomposers are not present?

The carbon they contain becomes trapped. Over millions of years, these remains form fossil fuels,

They are trapped in the bottom of the ocean or in bogs.

Combustion

- Plants that die are not fully decomposed by saprobionts, and their bodies form layers of sediment that can accumulate over millions of years, locking carbon into the ground

- This sediment is a store of energy and can form fossil fuels

- When fossil fuels are burnt, carbon dioxide is returned to the atmosphere

Fluctuations in atmospheric carbon dioxide

- Carbon dioxide levels fluctuate throughout the day

- Photosynthesis only takes place in the light, and so during the day, photosynthesis removes CO2 from the atmosphere

- However, respirations occurs constantly, so atmospheric carbon dioxide levels are higher at night than during the day

- CO2 levels are lower in Summer than in Winter, where photosynthesis is lower

Why is atmospheric carbon dioxide levels increasing?

- Combustion of fossil fuels

- Deforestation

Why is global warming bad?

- Warmer oceans dissolve less gas

- Therefore, global warming is reducing the carbon bank in the oceans, and releases more CO2 into the atmosphere