The Carbon Cycle On Earth

Question 1

What are the major stores of carbon?

Answer 1

• lithosphere = 99.9% stores in sedimentary rock, stored in fossil fuels
• atmosphere = co2 and methane
• hydrosphere = co2 dissolved in rivers, lakes and oceans
• biosphere = stored in tissue of living organisms —> transferred to soil when organisms die and decay
• cryosphere = permafrost, decomposing plants and animals have frozen into the ground

Question 2

What is carbon?

Answer 2

• found both in organic and in organic stores
• mainly stores in the mantle
• closed system

Question 3

Carbon sink

Answer 3

A store that absorbs more carbon than it releases

Question 4

Carbon source

Answer 4

A store that releases more carbon than it absorbs

Question 5

Carbon transfer

Answer 5

Transfers carbon between stores

Question 6

Driving changes in the carbon cycles stores (FLOWS + TRANSFERS)

Answer 6

• Photosynthesis
• respiration
• decomposition
• combustion
• carbon sequestration (oceans and sediments_
• weathering

Question 7

Photosynthesis (FLOW + TRANSFER)

Answer 7

• transfers carbon stores in the atmosphere to the biomass
• fast
• plants an phytoplankton use energy from the sub to change co2 and water into glucose and oxygen

Question 8

Respiration (FLOW + TRANSFER)

Answer 8

• transfers carbon from living organisms to the atmosphere
• plants and animal streak down glucose = energy and release co2 and methane

Question 9

Decomposition (FLOW + TRANSFER)

Answer 9

• transfers carbon from dead biomass to the atmosphere and soil
• fungi and bacteria break down organisms
• fast

Question 10

Combustion (FLOW + TRANSFER)

Answer 10

• Transfers carbon stores in living, dead or decomposed biomass to the atmosphere through burning
• wildfires cause carbon flow
• fast

Question 11

Carbon sequestration (FLOW + TRANSFER)

Answer 11

• carbon from the atmosphere can be sequestrated (captures and held) in sedimentary rock or as a focal fuel
• form over millions of years wage dead animals and plants fall to ocean floor = then compared
• carbon in fossil fuels is released when burnt

Question 12

Weathering (FLOW + TRANSFER)

Answer 12

• chemical weathering transfers carbon from the atmosphere to the hydrosphere and biosphere
• atmospheric carbon = reacts with water vapour to form acid rain = when rain falls it reacts with rocks and dissolves them

Question 13

What are the scales of carbon stores?

Answer 13

• local scale = trees a Bros rising co2, leaf litter decomposing
• sere scale = deciduous wood, hydrosphere —> water/pond
• continental = co2 removed by dissolving in water to form carbon acid

Question 14

What are the physical factor affecting the carbon cycle?

Answer 14

• wildfires
• volcanic activity

Question 15

Physical factors - wildfires

Answer 15

• rapidly transfer large quantities of carbo from biomass to the atmosphere
• loss of vegetation = decreases photosynthesis —> less carbon removed from the atmosphere
• longer term can encourage plant growth

Question 16

Physical factors - volcanic activity

Answer 16

• carbon stores within the earth in magma is released during volcanic eruptions
• between 130-180 mill tones of co2 is released into the atmosphere each year c

Question 17

Human factors affecting the carbon cycle

Answer 17

• fossil fuel extraction and use
• deforestation
• farming practices
• land use changes

Question 18

Human factor - fossil fuel extraction and use

Answer 18

• extracting and burning fossil fuels releases co2
• without human intervention = co2 would remain sequestrated in the lithosphere

Question 19

Human factor - deforestation

Answer 19

• forests cleared for agriculture, logging or new developments
• clearance reduces the size of carbon store

Question 20

Human factor - farming practices

Answer 20

• animals release co2 and methane when they respire and digest food
• ploughing releases co2 stores in soil
• mechanisation of farming practices also increases co2 emissions

Question 21

Human factors - land use changes

Answer 21

• natural or agricultural land changed to urban
• vegetation removed = reduces carbon storage in biosphere
• concrete production release co2

Question 22

Carbon budget

Answer 22

• difference between he inputs and outputs of carbon into a subsystem and outputs of carbon from it
• the balance of inputs and outputs determines wither it is a carbon source or sink