carbon cycle

Question 1

where is carbon found?

Answer 1

• carbon can be found in organic and inorganic stores
• organic - carbon is found in living things
• inorganic - carbon is found in non living things e.g. rocks

lithosphere:
- over 99.9% of carbon on earth is stored in sedimentary rocks such as limestone
- 0.004% is stored in fossil fuels

hydrosphere:
- carbon dioxide is dissolved in rivers, lakes and oceans
- oceans are the 2nd largest store of carbon on earth —> the majority of carbon is found deep in the ocean

biosphere:
- 0.004% of earths total carbon is found in living organisms —> when organisms die and decay, this carbon is transferred to the soil (pedosphere)

atmosphere:
- carbon is stored in the atmosphere as CO2 and methane
- the atmosphere contains around 0.001% of the earths carbon

cyrosphere:
- less than 0.01% of earths carbon is stored in the cryosphere

Question 2

carbon cycle flows

Answer 2

inputs:
- volcanic eruption
- burning fossil fuels
- wildfires
- respiration
- ocean loss

outputs:
- photosynthesis
- sequestration
- ocean uptake
- chemical weathering
- decomposition

Question 3

physical factors that affect the carbon cycle

Answer 3

climate
colder temperatures:
- lower temps —> less photosynthesis —> plant growth decreases —> less CO2 absorbed
- colder oceans absorb more CO2 from the atmosphere
warmer temperatures:
- higher temps —> more photosynthesis —> increased plant growth —> more CO2 absorbed
- warmer oceans absorb less CO2 from the atmosphere —> more CO2 in atmosphere

wildfires
- short term: (wildfires lead to more carbon being released into the atmosphere) loss of vegetation —> photosynthesis decreases —> less carbon removed from the atmosphere
- long term: (wildfires lead to less carbon being released into the atmosphere) soil can become more fertile after wildfires —> encourages the growth of new plants —> plants take in carbon from the atmosphere for photosynthesis

volcanic activity
- carbon stored within the earth is released during volcanic eruptions —> carbon is transferred from the lithosphere to the atmosphere
- recent volcanic eruptions have released much less CO2 than human activities

Question 4

human factors that affect the carbon cycle

Answer 4

fossil fuel extraction and use:
- extracting and burning fossil fuels: we need fossil fuels for many things e.g. heating up housing and powering vehicles etc —> this releases CO2 into the atmosphere
- as population has increased overtime, fossil fuel use has increased overtime

deforestation:
- deforestation leads to less leaf litter —> humus isn’t formed (contains nutrients that helps plants grow) —> soil becomes less fertile and plant growth decreases —> amount of CO2 taken in by plants decreases
- forests may be cleared for agriculture, logging, or to make space for housing —> reduces size of carbon stores —> less carbon can be stored in trees and more carbon will enter the atmosphere
- a lot of the deforested trees are burnt —> releases CO2

urbanisation:
- due to urbanisation, more houses have to be built —> trees are removed to make way for buildings —> reduces size of carbon stores —> less carbon stored in trees and more carbon will enter the atmosphere
- lots of concrete is used when urban areas expand —> concrete production releases lots of CO2 —> releases CO2 into the atmosphere

farming:
- population has increased —> food production has increased —> carbon emissions from farming practises have increased e.g. growing rice in rice paddies releases a lot of methane —> more carbon stored in the atmosphere// animals release CO2 and methane into the atmosphere when they respire and digest food —> carbon moves from the biosphere to the atmosphere

Question 5

carbon budget