Carbon Cycle - Global Distributions

Question 1

Major stores

Answer 1

Biosphere - 1.4% global store

Hydrosphere- 27% global store

Lithosphere - 71% global store

Atmosphere - 0.5% global store

Question 2

Biosphere as Carbon store

Answer 2

1.4%

Ecosystem get CO2 from atmosphere.

Plants absorption as gas into cells
Photosynthesise to chemically concert CO2 to carbon-based sugar molecules.

Some organic matter produced in plants- consumption

can be stored in soil as organic matter for 100 years

Decomposition - release in atmosphere

Question 3

Hydrosphere as carbon store

Answer 3

CO2 enters ocean through diffusion

Once dissolved in sea water - CO2 can remain or be converted into carbonate or bicarbonate

Some sea life biologically fix bicarbonate with calcium to produce calcium carbonate

This is used to make shells/body parts for coral, algae etc

When organism die, the shells and body parts sink to ocean floor —> accumulate as carbon-rich deposits

After a long time these deposits are altered into sedimentary rocks

Most carbon is stored in deep ocean floor -/> accumulate as carbonate rich deposits

After a long time, these deposits are altered into sedimentary rocks

Most carbon is stored in deep oceans

Less than 5% found near ocean surface

Question 4

Lithosphere as carbon store

Answer 4

71% of global store

Long term store and takes millions of years to form

CO2 stored here in organic and inorganic forms
Inorganic - fossil fuels - coal, oil, natural gas and carbonate based sedimentary deposits eg limestone

Organic forms of carbon in lithosphere: litter, organic matter which becomes humus in souls

Some CO2 is released from interior of lithosphere by volcanoes - subduction

Question 5

Atmosphere as carbon store

Answer 5

0.5% of global store

Stored as gas - CO2 - natural GHG- warms
Scientists estimate Earth is 25 degrees due to green house effect