1. Matter such as water and carbon are constantly cycled on Earth. 2. The water cycle has four main stages: evaporation, condensation, precipitation, collection.
3. Living things contain carbon. This is called organic matter. Carbon is cycled on Earth. 4. Carbon dioxide is removed from the atmosphere by green plants during photosynthesis and is absorbed by the oceans.
5. Carbon dioxide is released by aerobic respiration, the burning of fossil fuels, decomposition, the movement of water in the oceans and volcanic activity.
6. Carbon is stored in plant and animal tissue, in the wood in trees, fossil fuels and the oceans.
7. Photosynthesis: Carbon dioxide + Water + Light energy
6CO2 + 6H2
8. Respiration: Glucose + Oxygen
C6 H12 O6 + 6O2 O + Light energy
Chlorophyll Chlorophyll
Glucose + Oxygen C6 H12 O6 + 6O2
Carbon dioxide + Water + Energy 6CO2 + 6H2 O + Energy
9. Decomposition is the way in which living organisms (mainly bacteria and fungi) break down dead organic matter or waste. This process releases nutrients into the environment.
10. Dead plants and animals that are not completely broken down may eventually form fossil fuels.
11. Combustion is the release of heat energy from a fuel using oxygen: Fossil fuel + Oxygen
(e.g. Methane) CH4
+ 2O2 CO2 + 2H2 Carbon dioxide + Water vapour + Heat energy O + Heat energy
12. Carbon dioxide levels in the atmosphere vary depending on the season. They are lower in spring and summer as more photosynthesis is taking place, and higher in autumn and winter as less photosynthesis is taking place.
13. Carbon sinks are reservoirs that store large amounts of carbon compounds. The main natural carbon sinks are oceans and forests.
14. The global carbon budget is a way of describing the amount of carbon dioxide being released into the atmosphere compared with the amount being removed from it.
