The Global Carbon Cycle

Question 1

Name 5 processes that transfer carbon

Answer 1

• Photosynthesis
• Respiration
• Decomposition
• Burning fossil fuels
• Carbon sequestration

Question 2

What can the global carbon cycle be subdivided into?

Answer 2

• Geosphere

- Biosphere

Question 3

What is the Geosphere carbon cycle?

Answer 3

Operates at slow rate of thousands to millions of years

Question 4

What is the Biosphere carbon cycle?

Answer 4

Operates at fast rate of seconds to hundreds of years

Question 5

How is carbon stored in the atmosphere?

Answer 5

• CO² and Methane

- 766 billion metric tons

Question 6

How is carbon stored in the biosphere?

Answer 6

• Organic molecules in living and dead plants and animals
• Soil as organic matter from dead plant material and activity of microorganisms
• Decay process releases CO² into atmosphere
• Plants: 610 billion metric tons, Soil: 1600 billion metric tons

Question 7

How is carbon stored in the oceans?

Answer 7

• Dissolved CO² in water
• Calcium carbonate in shells of marine life, fall to sea floor becoming marine sediments
• Located at great depths, 4% found at surface
• 40,000 billion metric tons

Question 8

How is carbon stored in the lithosphere?

Answer 8

• Fossil fuels (Coal, oil and gas)
• Sedimentary rock e.g. Limestone and chalk
• Largest store of carbon (100,000 billion metric tons)

Question 9

What is the carbon balance?

Answer 9

• Carbon reservoirs acts as both sources (Add carbon to atmosphere) and sinks (Removing carbon from atmosphere)
• All sources and sinks are equal then carbon cycle is in balance

Question 10

What are fluxes?

Answer 10

• Movement of carbon between different reservoirs
• Each flux is a chemical reaction or physical process
• Each flux take carbon out of one store and put it in another e.g. Photosynthesis

Question 11

Give an example of carbon flow from the Atmosphere to Biosphere

Answer 11

Plants use CO² in process of photosynthesis and carbon is locked in plant material, passed along food chain to herbivores and later carnivores (Biological pump in oceans)

Question 12

Give an example of carbon flow from the Biosphere to Atmosphere

Answer 12

Released as CO² by plant and animal organisms through respiration

Question 13

Give an example of carbon flow from the Atmosphere to Ocean

Answer 13

CO² gradually diffuses into oceanic waters

Question 14

Give an example of carbon flow from the Ocean to Lithosphere

Answer 14

Coral and shelled organisms die, calcium carbonate sinks to bottom of ocean, over millions of years compressed into sedimentary rock

Question 15

Give an example of carbon flow from the Lithosphere to Atmosphere

Answer 15

Carbon stored in lithosphere released during volcanic eruptions

Question 16

Outline the ‘slow carbon cycle’

Answer 16

• Takes millions of years
• Carbon stored in sedimentary rock
• CO² released from sedimentary deposits through weathering and volcanic activity

Question 17

Outline the ‘fast carbon cycle’

Answer 17

• Takes place within lifetime
• Movement of carbon through food chains
• Photosynthesis absorbs carbon in minutes, respiration releases carbon in seconds

Question 18

Give 4 facts on the global carbon cycle

Answer 18

• Produce 30 gigatons of CO², atmosphere can only absorb 40% = 18 gigaton excess
• 80% carbon locked up in rocks
• Ocean absorbs 1/4 of anthropogenic carbon
• CO² absorbed by ocean through diffusion and stored as carbonic acid

Question 19

How have humans affected the carbon cycle?

Answer 19

• Use of coal, oil, gas and cement grown exponentially after WW2
• Land use change and exhaustion of fossil fuels largest impacts
• 90% anthropogenic carbon from combustion of fossil fuels

Question 20

Where does carbon on Earth come from?

Answer 20

1) Explosion of supernova
2) Reactions occur - 2 Helium = Beryllium, Beryllium + Helium = Carbon
3) Carbon heavy element, conglomerates together - Dragged to centre of solar system, Earth is largely carbon based (Central planet)

Question 21

What is carbon sequestration?

Answer 21

Process by which CO² is either removed from atmosphere or diverted from emission sources and stored in ocean, terrestrial environments and geological formations

Question 22

Give a danger associated with artificial sequestration

Answer 22

CO² deposits leak, gas could harm humans and environment

Question 23

Give the formula for photosynthesis

Answer 23

Carbon dioxide + Water GOES TO Glucose + Oxygen