PhysicsChapter 10: Earth's Climate
The Biosphere and Carbon Cycle
The biosphere
Definition
The biosphere includes all living organisms and ecosystems on Earth. The carbon cycle describes the movement of carbon between the atmosphere, oceans, living organisms, soils and rocks.
Photosynthesis
Carbon is continuously exchanged between different parts of the Earth system. Plants remove carbon dioxide from the atmosphere and use it to produce organic matter. A simplified equation is: **CO₂ + H₂O + light energy → organic matter + O₂**
Respiration
Living organisms release carbon dioxide back into the atmosphere through respiration.
Decomposition
When organisms die, decomposers break down organic material and return carbon to soils, water and the atmosphere.
Ocean Exchange
Oceans both absorb and release carbon dioxide.
Long-Term Storage
Carbon can be stored for long periods in: soils; sediments; rocks; fossil carbon reservoirs.
Climate Link
Carbon dioxide is a greenhouse gas, so changes in atmospheric CO₂ can influence Earth's energy balance.
Formula / Key Relation
A simplified reservoir balance is: **Change in carbon storage = Carbon inputs − Carbon outputs**
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Review the key facts, formulas and checks before you move on.The Biosphere and Carbon Cycle
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CARBON CYCLE
- Atmosphere ↔ Plants ↔ Animals ↔ Soil ↔ Ocean ↔ Rocks
60-second revision
- Biosphere = living part of Earth.
- Carbon constantly moves between reservoirs.
- CO₂ links the carbon cycle with climate.
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