3.1.1.3 The Carbon Cycle

Question 1

what are the gaseous carbon compounds?

Answer 1

CO2 and methane (CH4)

Question 2

what are the liquid carbon compounds?

Answer 2

carbonic acid, calcium bicarbonate

Question 3

what is the solid carbon compound?

Answer 3

carbonate rocks

Question 4

how is carbon stored in the atmosphere?

Answer 4

as co2 - 0.04% of the atmosphere or 400parts per million

or methane

Question 5

where is carbon found in the biosphere?

Answer 5

living vegetation, soil humus, peat, animals

Question 6

where is carbon found in the cryosphere?

Answer 6

in permafrost - e.g. canada

Question 7

where is carbon found in the lithosphere?

Answer 7

sedimentary rocks like limestone and chalk

fossil fuels / gas / oil

Question 8

where is carbon found in the hydrosphere?

Answer 8

dissolved CO2 in water and sea floor sediments
ocean plants
plankton

Question 9

rank largest to smallest magnitude of stores of carbon

Answer 9

lithosphere - sedimentary rocks
hydrosphere - oceans 
cryosphere - permafrost
biosphere - living biomass
atmosphere

Question 10

what are the transfer processes in the carbon cycle?

Answer 10

photosynthesis
repiration
decomposition
combustion
carbon sequestration
weathering

Question 11

outline the process of photosynthesis

Answer 11

plants use sunlight energy to produce glucose by converting CO2 into carbohydrates and oxygen is released back to the air

Question 12

outline the process of respiration

Answer 12

all living things use glucose and energy to carry out life functions through the process of respiration
CO2 and water are returned to the atmosphere
approx 50% of all carbon absorbed by photosynthesis is released by respiration

Question 13

outline the process of decomposition

Answer 13

when decomposers break up organic material
carbon is returned to the atmosphere as CO2 or methane
or passed into the soil as humus where it is used for plant growth

Question 14

outline the process of combustion

Answer 14

when organic material is burnt in the presence of oxygen and is converted into CO2, energy and water.
during this process carbon transfers from th bio/lithosphere to the atmosphere

Question 15

outline the process of carbon sequestration

Answer 15

long term transfer of carbon from the atmosphere to plants, soils, rocks and oceans

Question 16

outline the process of weathering

Answer 16

sedimentary rocks are broken down over time
when co2 is absorbed by water it forms carbonic acid which causes rocks to slowly dissolve. is eventually washed away into the oceans where it is used by marine life to build shells
transfers carbon from the lithosphere to the hydrosphere

Question 17

give examples of the fast carbon cycle when processes cause rapid change

Answer 17

photosynthesis - gaseous exchange between the ocean and atmosphere
wild fires - can transfer carbon rapidly from the biosphere to the atmosphere in huge amounts

Question 18

Outline the workings of the carbon cycle at the scale of an individual tree

Answer 18

Trees are 50% carbon

Photosynthesis, respiration and decomposition transfer between biosphere and atmosphere

Question 19

What is a lithosere?

Answer 19

A succession that takes place on bare rock like solidified lava flow or a raised beach

Question 20

Outline the role of volcanic activity in the carbon cycle

Answer 20

It transfers inorganic carbon from the lithosphere to the atmosphere.
Rock formed by igneous processes will slowly weather to carbonate solution

Question 21

How much carbon do volcanoes produce a year?

Answer 21

130-380 million tonnes

Question 22

Outline the role of wilfires in the carbon cycle

Answer 22

Combustion transfers large amounts of carbon from the biosphere to the atmosphere quickly
Extensive wildfires can turn forests from being a carbon sink to being a carbon sourcw

Question 23

Outline the impacts of hydrocarbon extraction and use on the carbon cycle

Answer 23

Carbon is released from long term storage as fossil fuels when burnt into the fast carbon cycle

Question 24

When did fossil fuel consumption and combustion rapidly increase?

Answer 24

1850s after industrial revolution

1950 chinese industrialisation led to a dramatic increase in the release of CO2

Question 25

What is the largest anthropogenic contributor to atmospheric CO2?

Answer 25

fossil fuel consumption

Question 26

What happens when limestone is processed into cement and why?

Answer 26

Significant amiunts of CO2 is released because sedimentary rocks like limestone are rich in calcium carbonates

Question 27

How do farming practices change the carbon cycle?

Answer 27

Practices such as ploughing, harvesting, rearing livestock and using large machinery release carbon
Methane is released in large amounts by livestock farming and rice cultivation

Question 28

How does deforestation impact the carbon cycle?

Answer 28

Removal of important carbon stores and sinks which reduces soil carbon content and closes down photosynthesis

Question 29

How much of anthropogenic CO2 emissions does deforestation account for?

Answer 29

20%

Question 30

How does land use change impact upon the carbon cycle?

Answer 30

Reduces vegetation coverage and replaces surface areas with impermeable surfaces
Urban settlements consume large amounts of energy
Cement is used in many urban structures which emits huge amounts of CO2

Question 31

What is the carbon budget?

Answer 31

The surplus or deficit of carbon once carbon output is subtracted from carbon input

Question 32

Outline the greenhouse effect

Answer 32

Short wave solar radiation passes throuhg the earth’s atmosphere and warms the earths surface
Long wave radiation is then emitted by the earth, some of which is absorbed by greenhouse gas molecules which directly warms the earths surface and atmosphere

Question 33

Why are greenhouse gases so important?

Answer 33

Without them, the earth would be completely frozen and too cold for life existence at -180°c

Question 34

Explain the concern about the enhanced greenhouse effect

Answer 34

The increased concentration of CO2 and methane means that more infra red radiation is being trapped in the atmosphere which explains why average global temperatures have increased about 0.8°c since 1880

Question 35

If CO2 levels continue to rise, how much is Earth temperatures expected to rise by 2100?

Answer 35

4°c

Question 36

How much have global temperatures risen since 1880?

Answer 36

0.8°c

Question 37

Outline possible impacts of increasing atmospheric CO2 on the land

Answer 37

Increase the length in growing season for plants, more CO2
Melting permafrost in tundra regions
Increasing extreme weather

Question 38

outline possible impacts of increasing atmospheric CO2 on the oceans

Answer 38

• increasing acidity of the water
• increasing temperatures cause phytoplankton numbers to decrease as they are used to cooler waters
• melting sea ice, rising sea levels
• fresh water entering the oceans reduces the salinity

Question 39

what does the increasing acidity of oceans impact?

Answer 39

dissolves shells of animals

causing coral bleaching

Question 40

what happens as a result of decreasing numbers of phytoplankton in the seas?

Answer 40

decrease the effectiveness of oceans being a carbon sink because plankton sequester carbon from the atmosphere

Question 41

how can warming oceans be a negative feedback loop?

Answer 41

some oceans support some species of phytoplankton and its growth. these species release DMA molecules which act as condensation nuclei for cloud formation . leads to potential global cooling

Question 42

why do warmer oceans mean less sea ice?

Answer 42

sea ice has a high albedo and reflects heat.

as it is replaced by water, which has a much lower albedo, there is further warming of the oceans.

Question 43

how much are sea levels expected to rise by 2100?

Answer 43

0.8 and 2m as a result of thermal expansion and melting ice sheets