3.1.1.3 The Carbon Cycle

Question 1

Describe the lithosphere

Answer 1

• Sedimentary rocks
• 99.9% of carbon

Question 2

Describe the hydrosphere

Answer 2

• Constant diffusion
• Carbon is dissolved in

Question 3

Describe the atmosphere

Answer 3

• Carbon dioxide accounts for less than 0.05% of the atmosphere
• Potent greenhouse gas

Question 4

Describe the biosphere

Answer 4

• 60% is peat
• 0.0012% of carbon

Question 5

Describe the cryosphere

Answer 5

• Permafrost
• less than 0 degrees for over 2 years

Question 6

Name the factors driving change in magnitude over time

Answer 6

• photosynthesis
• respiration and decomposition
• combustion
• carbon sequestration
• weathering

Question 7

Describe photosynthesis in relation to the carbon cycle

Answer 7

• Plants use energy from sunlight to combine carbon dioxide with water to form carbohydrates and oxygen
• Can be a long term store as trees live for ages

Question 8

Describe respiration in relation to the carbon cycle

Answer 8

Plants release co2 back into the atmosphere

Question 9

Describe decomposition in relation to the carbon cycle

Answer 9

Fungi and bacteria break down dead tissues off to form more simple inorganic substances
Carbon dioxide release is a byproduct of this process

Question 10

Describe combustion in relation to the carbon cycle

Answer 10

• Fossil fuels contain carbon captured by living organisms
• Since the industrial revolution these fuels have been mine and combusted for energy
• This releases CO2

Question 11

Describe the biological pump

Answer 11

Marine organisms such as phytoplankton use dissolved CO2 in photosynthesis, when these organisms die or get consumed, the carbon will sink to lower levels where it is sequestered

Question 12

Describe calcification

Answer 12

• Marine organisms use carbon to create their shells
• When they die, this carbon sinks and is sequestered

Question 13

Describe the ocean carbon pump

Answer 13

• Warm waters absorbs CO2
• Currents move this CO2 rich water to lower layers
• Sequestered

Question 14

Describe weathering in relation to the carbon cycle

Answer 14

• Weathering breaks down rocks on the surface which is then carried to the ocean
• Large particles accumulate on the shore and eventually form shale rock
• Smaller dissolved particles can be used in shells of marine organisms
• They die and limestone can be formed from the carbonate in the shells

Question 15

Name the two physical causes of change in the carbon cycle

Answer 15

• Wildfires
• Volcanoes

Question 16

How do wildfires change the carbon cycle

Answer 16

• Carbon stores in plants enters the atmosphere
• Soil exposure increases carbon release from decomposition
• Vegetation is replaced by young plants which stores less carbon
• Accounts for 5-10% of annual CO2 emissions

Question 17

How are wildfires changing over time

Answer 17

• Number have increased, especially in Western America
• Occurring 5x more often
• Lasting 5x longer

Question 19

What was significant about the eruption of Mt Pinatubo in 1991

Answer 19

It cooled the earth’s temperatures by 0.6 degrees

Question 20

Name the human factors causing change in the carbon cycle

Answer 20

• farming practices
• deforestation
• land use change

Question 22

How does decomposition impact the carbon cycle

Answer 22

• waste products are burned by combustion
• exposed soil increases erosion into rivers and accelerates decomposition

Question 23

How does change in land use impact the carbon cycle

Answer 23

• 2% of the world is covered by urban areas
• this area produces 97% of all emissions
• previous land was likely more valuable in storing carbon

Question 24

Define the carbon budget

Answer 24

A list of all the carbon pools (stores), an estimate of their size and a summary of all the fluxes that includes inputs and outputs

Question 25

Relationship between the water and carbon cycle and the atmosphere

Answer 25

• CO2 causes 20% of greenhouse effect
• water vapour accounts for 50%

Question 26

How does carbon support life on earth

Answer 26

• 18% of the human body
• 50% of biomass in trees
• essential for photosynthesis

Question 27

How does water support life on earth

Answer 27

• all life is supported by <1% of water

Question 28

What is significant about Boundary Dam, Canada

Answer 28

• practice carbon capture and storage
• cut emissions by 90%
• costs $800mn