1. What the spec says:
Factors driving change in the magnitude of these stores over time and space, including flows and transfers at plant, sere and continental scales. Photosynthesis, respiration, decomposition, combustion, carbon sequestration in oceans and sediments, weathering.
Intro video

2. Factors driving the change in the magnitude of major stores of carbon.

3. Intro:
Carbon stores represent a natural reservoir or carbon before it is transferred.
Each store can be both a carbon source and a carbon sink
Carbon source release carbon whereas carbon sinks absorb it.
The size of the Earth’s carbon stores fluctuate over time.

4. Fast and slow carbon cycles
With its chemical flexibility, carbon takes many forms and goes through many processes (aka flows and transfers). Some transfers are very rapid and some are very slow – taking millions of years.
There are 4 major cycles that operate at different timescales:
The fast organic cycle – transfer of carbon between plants and animals moving carbon between the atmosphere, soil and biosphere over months and centuries.
The fast non-organic cycle – transfer of carbon between the ocean and atmosphere with rates depending on the conditions in both.
The slow organic cycle – long term sequestration of the remains of sea creatures and terrestrial forests as fossil deposits of oil, coal and gas over hundreds of millions of years.
Slow non-organic cycle – the transfer of carbon from the atmosphere to the hydrosphere then to carbon rich rocks in the lithosphere. Which are then recycled back to the atmosphere via tectonic processes.

5. Flows and transfers at plant, sere and continental scales

6. Flows and transfers of carbon at a plant scale: a tree

7. Flows and transfers of carbon at a plant scale: a tree
Wood acts a carbon store
Wood is about 50% carbon
Carbon is being transferred between that atmosphere, biosphere and soil via the processes of photosynthesis, respiration and decomposition.

8. Flows and transfers of carbon at a ‘sere’ scale: a forest

9. Flows and transfers of carbon at a ‘sere’ scale: a forest
A ‘sere’ is a stage in the succession of vegetation in an ecosystem.
A lithosere is vegetation succession that occurs on bare rock, a hydrosere occurs in fresh water e.g. a pond, a halosere occurs in salt rich conditions e.g. salt marshes and a psammosere occurs in sandy areas e.g. sand dunes.
A final stage of a sere is reached when environmental equilibrium or balance is reached. The nature of the vegetation is mainly due to the climate and is therefore known as the climatic climax. The climatic climax for a lithosere in the UK will usually be a deciduous wood.
The carbon cycle at a ‘sere’ scale is much more complex involving numerous different stores, many transfers which all vary over space and time.

10. Flows and transfers of carbon at a continental scale

11. Flows and transfers of carbon at a continental scale
The carbon cycle at a continental scale involves all 4 of the fast and slow carbon cycles.
The interrelationships between the stores is very complex.
The rate of transfers varies over time due to changing conditions on the planet.
Human activity has added another more complex dimension at this scale especially with the increased addition of carbon dioxide to the atmospehere.