1.11. The Carbon Cycle: Stores

Question 1

Atmosphere to biosphere

Answer 1

Photosynthesis

Question 2

Biosphere to atmosphere

Answer 2

• respiration
• combustion
• decomposition

Question 3

Biosphere to lithosphere

Answer 3

Sequestration

Question 4

Hydrosphere to lithosphere

Answer 4

Sequestration

Question 5

Cryosphere to atmosphere

Answer 5

Permafrost melting

Question 6

Atmosphere to hydrosphere

Answer 6

Weathering

Question 7

Hydrosphere to atmosphere and atmosphere to hydrosphere

Answer 7

Ocean uptake and loss

Question 8

Lithosphere

Answer 8

• largest store
• over 99.9% of carbon on Earth is stored in sedimentary rocks formed at the bottom of the sea
  0.004% stored in fossil fuels

Question 9

Biosphere

Answer 9

• 0.004% of Earth’s carbon stored in tissues of living organisms and transferred to soil when organisms die and decay
• Found in different types
  - 1100 Gtc in biomass of living plants
  - 2500 Gtc in soil
  - 1550 Gtc is organic biomass
  - 950 Gtc in inorganic carbon
• found on all continents covering 4 million square kilometres

Question 10

Atmosphere

Answer 10

• carbon stored as CO2 and methane in atmosphere
• current levels around 0.001% of Earth’s carbon
• as high as 7000 parts per million (ppm) 500 years ago
• as low as 180 ppm 2 million years ago- quaternary age

Question 11

Cryosphere

Answer 11

• contains less than 0.001% of Earth’s carbon
• most of cryosphere’s carbon is found in soil of permafrost
• decomposing plants and animals frozen in ground thaw and release methane

Question 12

Hydrosphere

Answer 12

• carbon dioxide dissolved in rivers, lakes and oceans
• oceans are the second largest carbon store on earth - 0.04%
• majority of carbon found deep in ocean
• small amount of carbon at ocean surface exchanged with atmosphere via phytoplankton at euphotic zone