WCC: Carbon Cycle - Global Distribution of Carbon Stores

Question 1

Name the 5 main physical systems that store carbon.

Answer 1

Biosphere
Lithosphere
Cryosphere
Hydrosphere
Atmosphere

Question 2

What are fluxes?

Answer 2

The changes in the amount of carbon held in each store over timescales ranging from a few minutes to millions of years.

Question 3

Amount of carbon in marine and sedimentary rocks

Answer 3

Up to 100 million GtC

Question 4

Amount of carbon in the ocean

Answer 4

38,000 GtC

Question 5

Amount of carbon in fossil fuel deposits

Answer 5

4,000 GtC

Question 6

Amount of carbon in soil organic matter

Answer 6

1,500 GtC

Question 7

Amount of carbon in the atmosphere

Answer 7

750 GtC

Question 8

Amount of carbon in terrestrial plants and animals

Answer 8

560 GtC

Question 9

Chemical formula for methane

Answer 9

CH4

Question 10

Where is carbon stored in the hydrosphere?

Answer 10

In deep and shallow ocean waters in:
Ocean sediments
Dissolved CO2
Shells

Question 11

Briefly outline why carbon is important (3 reasons)

Answer 11

It is needed by all plants and animals for life, and provides a source of food for plants and animals. It has has provided fuel for human industries since pre-history in the form of fossil fuels, for example in the industrial revolution which was essential in the UK’s development as a leading economy. Changes in the carbon cycle have led to climate change, making them arguably the greatest challenge facing the planet.

Question 12

What is carbon?

Answer 12

A basic element needed by all life to survive

Question 13

What is a carbon sink?

Answer 13

A store that absorbs more carbon than it releases

Question 14

What is a carbon source?

Answer 14

A store that releases more carbon that it absorbs

Question 15

What different geographical scales can carbon stores be identified at?

Answer 15

Individual plants
Seres
Global scales - oceans and continents

Question 16

Briefly describe why carbon is unevenly distributed around the world.

Answer 16

The uneven distribution of land and sea has a large impact on the global distribution of carbon stores such as oceans, soils and rocks. Fossil fuels are only found in certain parts of the world, making carbon emissions high in these areas due do industrial burning of fossil fuels.

Question 17

What is the carbon cycle?

Answer 17

The complex processes carbon undergoes as it is transformed from organic carbon into inorganic carbon and back again

Question 18

Why does following the carbon cycle allow us to study energy flows on Earth?

Answer 18

Most of the chemical energy needed for life is stored in organic compounds as bonds between carbon atoms and other atoms

Question 19

What is the name for the different forms in which carbon can move through the cycle?

Answer 19

Carbon compounds

Question 20

How is carbon stored in a solid form? Which stores store solid carbon?

Answer 20

It is combined with other elements and stored in living things, minerals of rocks and soil, and ice.

Question 21

What are the 2 pure solid forms of carbon?

Answer 21

Graphite and diamond

Question 22

How is carbon stored as a liquid?

Answer 22

It is dissolved in water

Question 23

What are 2 important liquid forms of carbon?

Answer 23

Carbonic acid

Dissolved organic carbon

Question 24

How is carbon stored as a gas?

Answer 24

It is combined with other elements to form gases

Question 25

What are 2 important gaseous forms of carbon?

Answer 25

Carbon dioxide | Methane

Question 26

Name 5 important carbon compounds

Answer 26

``` Carbon dioxide Methane Calcium carbonate Hydrocarbons Bio-molecules ```

Question 27

Why is carbon dioxide the most studied form of carbon?

Answer 27

It has a profound effect on climate

Question 28

Why is it difficult to separate natural carbon cycles from those affected by human activity?

Answer 28

Human activity and anthropogenic CO2 fundamentally affect the carbon cycle and therefore climate

Question 29

What stores is carbon dioxide found in?

Answer 29

Atmosphere Oceans Soils

Question 30

What stores is methane found in?

Answer 30

Atmosphere Oceans Soils Sedimentary rocks

Question 31

What stores is calcium carbonate found in?

Answer 31

Calcareous rocks Oceans Skeletons and shells of ocean creatures

Question 32

What stores are hydrocarbons found in?

Answer 32

Sedimentary rocks

Question 33

What stores are bio-molecules found in?

Answer 33

Living things

Question 34

What is carbon dioxide?

Answer 34

A gas formed when carbon combines with oxygen. | Chemical formula: CO2

Question 35

What is methane?

Answer 35

A powerful greenhouse gas formed when carbon combines with hydrogen. Chemical formula: CH4

Question 36

What is calcium carbonate?

Answer 36

A solid carbon compound | Chemical formula: CaCO3

Question 37

What are hydrocarbons?

Answer 37

Organic compounds consisting of hydrogen and carbon that can be solids, liquids or gases

Question 38

What are bio-molecules?

Answer 38

Complex carbon compounds produced in living things

Question 39

What is anthropogenic CO2?

Answer 39

Carbon dioxide generated by human activity

Question 40

What unit do the IPCC use to measure the amount of carbon in various stores?

Answer 40

GtC - A gigatonne of CO2

Question 41

What is flux of carbon within the cycle measured in?

Answer 41

GtC/years - gigatonnes of carbon per year

Question 42

What is the Earth's primary source of carbon?

Answer 42

the Earth's interior - carbon is stored in the mantle

Question 43

Where can carbon escape from the mantle?

Answer 43

At constructive and destructive plate boundaries and hot-spot volcanoes

Question 44

How is CO2 released at destructive plate boundaries?

Answer 44

Through the metamorphism of carbonate rocks subducting with the ocean crust

Question 45

How is carbon moved into long-term storage?

Answer 45

By burial of sedimentary rock layers

Question 46

Which sedimentary rocks store carbon in the long-term and in what form?

Answer 46

Coal and black shales store organic carbon from undecayed biomass Carbonate rocks like limestone store calcium carbonate

Question 47

Which physical system stores the largest amount of carbon?

Answer 47

The lithosphere

Question 48

What is the largest store of carbon?

Answer 48

Marine and sedimentary rocks

Question 49

What is the lithosphere?

Answer 49

The Earth's crust and uppermost mantle

Question 50

What is the pedosphere?

Answer 50

The uppermost layer of the lithosphere which chemically reacts to the atmosphere, hydrosphere and biosphere through the soil forming process

Question 51

Amount of carbon in peat

Answer 51

250 GtC

Question 52

Why is soil not entirely part of the lithosphere?

Answer 52

It is partly made of living organisms

Question 53

Give 2 examples of sedimentary rocks that are largely composed of carbon.

Answer 53

Limestones | Dolomite

Question 54

What forms fossil fuels?

Answer 54

Fossilised organic matter

Question 55

What are the 3 main fossil fuels?

Answer 55

Coal Oil Natural gas

Question 56

What are fossil fuels?

Answer 56

Hydrocarbons trapped within the lithosphere that release significant amounts of heat energy when they are burned

Question 57

What is peat?

Answer 57

An accumulation of partially decayed vegetation or organic matter unique to natural areas called peatlands or mires

Question 58

Why do sedimentary rocks contain large stores of carbon?

Answer 58

They are formed from the fossilised remains of marine organisms

Question 59

What are limestones primarily composed of?

Answer 59

Calcium carbonate

Question 60

Give an example of a limestone and why it stores a lot of carbon.

Answer 60

Chalk, which is composed primarily of the shells of single-celled, calcium carbonate secreting creatures

Question 61

Give 2 stores of inorganic carbon in the lithosphere.

Answer 61

Fossil fuels | Carbonate-based sedimentary deposits

Question 62

Give 3 stores of organic carbon in the lithosphere.

Answer 62

Litter Organic matter Humic substances found in soils

Question 63

Give the 4 main carbon stores in the lithosphere?

Answer 63

Marine sediments Soil organic matter Fossil fuels Peat

Question 64

How much carbon is there approximated to be stored in the oceans?

Answer 64

38,000 GtC

Question 65

How can ocean stores be divided up in order to measure the amount of oceanic carbon?

Answer 65

3 stores: - surface layer - intermediate and deep layer - organic matter

Question 66

How much oceanic carbon does the surface layer store?

Answer 66

900 GtC

Question 67

How much oceanic carbon do the intermediate and deep layers store?

Answer 67

37,000

Question 68

How much oceanic carbon does living organic matter store?

Answer 68

30 Gtc

Question 69

How much oceanic carbon does dissolved organic matter store?

Answer 69

700 GtC

Question 70

How do marine and sedimentary rocks form?

Answer 70

When organisms die, their dead cells and shells sink into deep water. Some material sinks right to the bottom where it forms layers of carbon-rich sediments. Over millions of years, chemical and physical processes may turn these sediments into rocks.

Question 71

What defines the surface layer of the ocean?

Answer 71

The layer at which sunlight can penetrate so photosynthesis can occur

Question 72

Briefly describe the global distribution of carbon within the hydrosphere.

Answer 72

Net sources of carbon in the eastern Pacific, Arabian Sea, south Atlantic and Southern Ocean. Also net sinks in the Southern Ocean and Pacific as well as the north Atlantic

Question 73

Briefly describe the global distribution of carbon in the lithosphere.

Answer 73

Large amount of carbon stored in northern Russia, Canada and Saudi Arabia

Question 74

What does the distribution of carbon within the terrestrial biosphere depend on?

Answer 74

The ecosystem

Question 75

Which terrestrial ecosystems store the largest amount of carbon?

Answer 75

Boreal forests

Question 76

Which terrestrial ecosystems store the largest amount of carbon?

Answer 76

Deserts

Question 77

What are the 5 main stores of carbon in the terrestrial biosphere?

Answer 77

``` Living vegetation Plant litter Soil hummus Peat Animals ```

Question 78

What percentage of carbon in the terrestrial biosphere is stored in plants?

Answer 78

19%

Question 79

What 2 factors influence the amount of carbon in living vegetation?

Answer 79

Location | Vegetation type

Question 80

Give an example of how location influences the amount of carbon stored in living vegetation.

Answer 80

It is estimated half of the carbon stored in forests is stored in high-latitude forests, and over a third is stored in low-latitude forests

Question 81

What are the 2 largest forest stores of carbon?

Answer 81

Russia's vast expanses of forest | Amazon Basin

Question 82

What percentage of the world's forest carbon is stored in Russian forests?

Answer 82

25%

Question 83

What percentage of the world's forest carbon is stored in the Amazon Basin?

Answer 83

20%

Question 84

What percentage of terrestrial carbon is stored in boreal forests?

Answer 84

26%

Question 85

What percentage of terrestrial carbon is stored in tropical forests?

Answer 85

20%

Question 86

What percentage of terrestrial carbon is stored in deserts?

Answer 86

5%

Question 87

What is plant litter?

Answer 87

Fresh, undecomposed and easily recognisable plant debris

Question 88

What factor directly affects the type of plant litter found in area?

Answer 88

The type of ecosystem

Question 89

Why is annual litter fall low in grasslands?

Answer 89

There is very little above ground perennial tissue in grasslands

Question 90

Where does soil hummus originate from?

Answer 90

Litter decomposition

Question 91

What is hummus?

Answer 91

A thick brown or black soil substance that remains after most organic litter has decomposed

Question 92

How does hummus get dispersed throughout soil?

Answer 92

By soil organisms such as earthworms

Question 93

In all forests combined, how is carbon distributed between biomass and soil?

Answer 93

Around 30% is stored in biomass and 70% in soil.

Question 94

In tropical forests, how is carbon distributed between biomass and soil? How is this different to other forests.

Answer 94

Carbon is distributed evenly with 50% in biomass and 50% in soil. Other types of forests tend to store the majority in soil.

Question 95

Amount of carbon stored in soil inorganic matter

Answer 95

1000 GtC

Question 96

What does soil inorganic carbon consist of?

Answer 96

Carbon itself as well as carbonate materials such as calcite, dolomite and gypsum

Question 97

Total amount of carbon stored in soil

Answer 97

2,500 GtC

Question 98

Briefly describe how the magnitude of carbon stores varies between the hydrosphere, lithosphere, biosphere and atmosphere.

Answer 98

The lithosphere contains the largest amount of carbon, mainly in the form of marine and sedimentary rocks. The hydrosphere has the next largest carbon store within the ocean. The carbon stored in soil can be included in both the lithosphere and the biosphere, and is approximately 3 times larger than the atmospheric carbon store. However there is still more carbon stored in the atmosphere than in the rest of the biosphere, consisting of living plants and animals.

Question 99

How do terrestrial animals get carbon?

Answer 99

From their diet

Question 100

How do plants and marine animals get carbon?

Answer 100

They extract it from the atmosphere and oceans

Question 101

What do plants and marine animals use carbon for?

Answer 101

To build organic structures such as plant material and sea shells

Question 102

What happens to the carbon when plants and marine animals die?

Answer 102

They decompose and the carbon is returned either to the ocean, sea bed, atmosphere or soil

Question 103

What conditions does peat form in?

Answer 103

Wetland conditions

Question 104

How does peat form?

Answer 104

Almost permanent water saturation obstructs flows of oxygen from the atmosphere into the ground. This creates anaerobic conditions that slow down the rates of plant litter decomposition.

Question 105

Describe the global distribution of peat.

Answer 105

Peatlands occur on all continents in nearly all ecosystems and altitudes.

Question 106

How large an area do peatlands cover globally?

Answer 106

4 million km^2

Question 107

What percentage of global land and freshwater surface is covered by peatlands?

Answer 107

3%

Question 108

How are animals important in the carbon cycle?

Answer 108

They are important in generating the movement of carbon through the cycle

Question 109

What percentage of the atmosphere is CO2?

Answer 109

0.04%

Question 110

Give 2 important uses of atmospheric CO2

Answer 110

Regulates the Earth's surface temperature | Used by plants for photosynthesis

Question 111

How do atmospheric carbon stores affect rain?

Answer 111

Atmospheric CO2 makes rain slightly acidic, as CO2 reacts with water vapour to form carbonic acid. Increased atmospheric CO2 increases the acidity of rain.

Question 112

What is the main impact of the natural acidity of rain?

Answer 112

Weathering

Question 113

What is the largest store of cryospheric carbon?

Answer 113

Permafrost

Question 114

What regions is permafrost found in?

Answer 114

Tundra regions

Question 115

How does permafrost store carbon?

Answer 115

Upon death, plants and animals are frozen due to the cold climate, preventing decomposition. This means that the carbon is trapped in the permafrost and not released back into the atmosphere, water, or soil.