The Carbon Cycle

Question 1

Give examples of carbon in solid, liquid and gas form - Carbon Cycle

Answer 1

Solid - organic matter, graphite, diamond, coal
Liquid - Carbonic acid, dissolved organic carbon, liquid pure carbon
Gas - CO2, Methane, natural gas (fossil fuel)

Question 2

Define what carbon is and the functions of carbon - Carbon Cycle

Answer 2

An element crucial to all living things on Earth, especially organic matter. Has recently been used as an energy source to power our lifestyles.

Question 3

What stores of carbon are there in the Biosphere and Lithosphere? - Carbon Cycle

Answer 3

Biosphere - in biomass

Lithosphere - coal, oil, gas, rocks, soils, from plate boundaries, volcanoes etc.

Question 4

What stores of carbon are there in the atmosphere, cryosphere and hydrosphere? - Carbon Cycle

Answer 4

Atmosphere - stored as CO2, fossil fuel emissions
Cryosphere - in permafrost
Hydrosphere - can dissolve into oceans

Question 5

What percentage of all carbon exists within the lithosphere? How many gigatonnes of carbon is this? - Carbon Cycle

Answer 5

99.9% of all carbon exists within the lithosphere, amounting to 100 million gigatonnes of carbon.

Question 6

What percentage of all carbon exists within the atmosphere? How many gigatonnes of carbon is this? - Carbon Cycle

Answer 6

0.001% of all carbon exists in the atmosphere, amounting to 800 gigatonnes.

Question 7

Which biome contains the most carbon? Which biome contains the least carbon? Why is this? - Carbon Cycle

Answer 7

The tropical and subtropical rainforest biome contains the most carbon because this biome has a very high density of vegetation.
The tundra contains the least biome as little photosynthesis occurs here due to sparse vegetation which lives off minimal sunlight and water.

Question 8

Is the carbon cycle an open or closed system? - Carbon Cycle

Answer 8

On a global scale, the carbon cycle is closed, yet at a local scale the carbon cycle is open.

Question 9

How is carbon transferred between the lithosphere/biosphere and the atmosphere? (Name processes) - Carbon Cycle

Answer 9

Photosynthesis of organic matter, respiration, volcanic activity, decomposition of organic matter, soil respiration.

Question 10

How is carbon transferred between the atmosphere and the ocean? - Carbon Cycle

Answer 10

Photosynthesis by phytoplankton, respiration by marine life, diffusion between the oceans and the atmosphere.

Question 11

How is carbon transferred between the deep ocean and the lithosphere? - Carbon Cycle

Answer 11

Carbon is buried in the form of organic matter in oceans and compacted over time to form sedimentary rocks.
BURIAL AND COMPACTION.

Question 12

How do humans cause transfers of carbon between the biosphere/lithosphere and the atmosphere? - Carbon Cycle

Answer 12

Humans extract fossil fuels (carbon) from the lithosphere and burn them (combustion) to release energy. This releases gaseous carbon into the atmosphere in the form of CO2.

Question 13

How do wildfires cycle carbon through the atmosphere and lead to a cycle in the presence of vegetation? - Carbon Cycle

Answer 13

Dry organic matter falls to the ground, which over time compiles before being ignited. This combustion of organic matter releases CO2 into the atmosphere and clears large areas of forest. Over time, this regrows as a secondary succession, which draws CO2 from the atmosphere, creating organic matter which then falls to the ground and the cycle repeats.

Question 14

What are the names of the 4 start points for primary succession? - Carbon Cycle

Answer 14

Lithosere - bare rock
Psammosere - sand dunes
Halosere - salt marshes/estuaries (salt water)
Hydrosere - lakes (freshwater)

Question 15

In what climate do primary successions from a) lithosere and b) psammosere originate? - Carbon Cycle

Answer 15

Lithosere - Bare rock

Psammosere - Sand dunes

Question 16

In what climate do primary successions from a) halosere and b) hydrosere originate? - Carbon Cycle

Answer 16

a) saltmarshes/estuaries (saltwater)

b) lakes (freshwater)

Question 17

What is a succession? What is it influenced by? - Carbon Cycle

Answer 17

A succession is the series of changes that take place over time as a plant community reaches a seral climax. Influenced by competition, number of new species and environmental changes.

Question 18

What happens in stages one and two of lithosere succession? - Carbon Cycle

Answer 18

1. Pioneer species colonise bare rock. These plants can survive with few soil and nutrients (hardy/resilient). Plants such as lichens and mosses. Creates a thin, immature soil.
2. Small, fast growing plants grow on thin soil, outcompeting mosses due to having better access to sunlight/deeper roots for more nutrients.

Question 19

What happens in stages three and four of lithosere succession? - Carbon Cycle

Answer 19

3. Larger shrubs outcompete grasses as soil deepens, containing more organic material (decomposition of grasses). Shrubs can absorb more water, light and nutrients (deeper roots).
4. Fast growing trees outcompete shrubs as they have better access to light, nutrients and water. Soil thickens due to decomposed organic matter.

Question 20

What happens in stage five of a lithosere succession? - Carbon Cycle

Answer 20

Slower growing trees such as oak trees dominate the ecosystem due to their thick, deep roots absorbing more water and nutrients, as well as having better access to light, encouraging their growth.

Question 21

What is the end of stage five of a lithosere succession known as? - Carbon Cycle

Answer 21

At the end of stage 5, the lithosere succession is said to have reached a CLIMATIC CLIMAX. The succession of evolution of plants has progressed as far as it can and the competition between plants is ended.

Question 22

Throughout a seral succession, what happens to the time, plant diversity, plant height, animal species diversity and carbon storage? - Carbon Cycle

Answer 22

ALL OF THESE FACTORS INCREASE as a seral succession progresses.

Question 23

What are carbon sinks? What are carbon sources? - Carbon Cycle

Answer 23

Carbon sinks are stores of carbon which sequester more carbon than they release.
Carbon sources are stores of carbon which release more carbon than they sequester.

Question 24

What are carbon fluxes? How are stores of carbon in flux differently? - Carbon Cycle

Answer 24

Carbon fluxes are changes in the amount of carbon held in a store over time.
Certain carbon stores are in flux at a greater speed than others, and some transfer carbon at higher volumes than others.

Question 25

How does an increase in CO2 levels lead to a temperature increase? - Carbon Cycle

Answer 25

An increase in CO2 levels in the atmosphere means that greater levels of infrared radiation are entrapped by the atmosphere, causing enhanced warming of the earth.

Question 26

How do colder temperatures impact the Carbon Cycle in terms of oceans and water? - Carbon Cycle

Answer 26

Colder oceans result in a reduction in marine plants, reducing the extraction of CO2 from the atmosphere for photosynthesis. Colder water also holds more CO2, meaning that it is more acidic and causes greater weathering.

Question 27

How do colder temperatures impact the Carbon Cycle in terms of organic matter and soils? - Carbon Cycle

Answer 27

Decomposition is slower in cold, slows transfer of carbon to soils, colder temperatures alter the location of rainforests, changing where carbon is concentrated within our natural habitats. Also affects photosynthesis and respiration.

Question 28

How do warmer temperatures impact the Carbon Cycle in terms of water and the oceans? - Carbon Cycle

Answer 28

Warm water holds less CO2, reducing its acidity, melting permafrost is caused by higher temperatures, potentially releasing entrapped methane and CO2.

Question 29

How do warmer temperatures impact the Carbon Cycle in terms of organic matter and soils? - Carbon Cycle

Answer 29

Warmer temperatures increase plant growth and levels of carbon storage, as well as altering biomes and expanding areas of rainforest. Decomposition faster in warm air, carbon transfers to soil quicker. More wildfires may occur, leading to rapid flux of CO2.

Question 30

What are the 4 different types of carbon cycle in terms of temporal cycling and living/non living things? - Carbon Cycle

Answer 30

ORGANIC AND INORGANIC CARBON CYCLE

LONG TERM AND SHORT TERM CYCLING

Question 31

Fluxes between which groups constitute organic and inorganic carbon cycles respectively? - Carbon Cycle

Answer 31

Organic = living things (plants, animals, soils)
Inorganic = non-living things (atmosphere/rocks/oceans)

Question 32

Describe the natural greenhouse effect. What happens to temperatures as a result? - Carbon Cycle

Answer 32

A residual volume of greenhouse gas exists in the atmosphere to regulate the temperature of the planet, allowing a certain amount of infrared radiation to remain within the atmosphere to warm the planet. Temperatures remain in a stable state of dynamic equilibrium.

Question 33

Describe the enhanced greenhouse effect and what impact this has on temperatures - Carbon Cycle

Answer 33

Human activities (carbon combustion/land use change) means that more GHG exists in the atmosphere, entrapping greater levels of infrared radiation within the atmosphere, causing a rise in global temperatures.

Question 34

How have hydrocarbons been formed over time? - Carbon Cycle

Answer 34

Ancient plants sequestered large amounts of carbon from the atmosphere. These plants were buried and compacted, forming sedimentary rocks, which later developed into carbon rich fossil fuels under the Earth’s surface.

Question 35

How have humans begun to harness fossil fuels? - Carbon Cycle

Answer 35

Humans have been extracting hydrocarbons since the 1750s and burning them to power industry, transport and our lives. This has resulted in the enhanced greenhouse effect.

Question 36

What percentage of anthropogenic carbon release is from fossil fuel combustion? - Carbon Cycle

Answer 36

90% of anthropogenic carbon release comes from fossil fuel combustion.

Question 37

How do farming practices impact the carbon cycle in terms of livestock? How do humans impact this? - Carbon Cycle

Answer 37

Digestion by ruminants (cattle) of grazing pasture releases methane. This has been exacerbated by humans breeding more and more livestock to meet demand for meat and dairy produce.

Question 38

What percentage of the USA’s methane emissions are due to cattle? - Carbon Cycle

Answer 38

20% of the USA’s methane emissions are due to the cattle industry.

Question 39

How do farming practices impact the carbon cycle in terms of arable farming? (Produce and fertilisers) - Carbon Cycle

Answer 39

Methane is produced as a by-product of rice farming in rice paddies. Additionally, the production of fertilisers is mostly done through the use of fossil fuels. This fossil fuel runs off into the soil and is then respired into the atmosphere.

Question 40

How do farming practices impact the carbon cycle in terms of machinery? - Carbon Cycle

Answer 40

Most intensive farming involves harvesting and farming through use of machinery which is powered by fossil fuels. Additionally, ploughing releases carbon as exposed soil can be easily weathered, allowing carbon to be released into water and the atmosphere.

Question 41

How does deforestation impact the carbon cycle in terms of land use change? - Carbon Cycle

Answer 41

Large areas of dense forest is felled through slash and burn to create space for agriculture/commercial purposes/urbanisation/mining/power. This removes carbon sinks and releases carbon into the atmosphere.

Question 42

What percentage of CO2 emissions is deforestation accountable for? Where does most deforestation occur? - Carbon Cycle

Answer 42

Deforestation is accountable for 20% of all global CO2 emissions. The majority of deforestation occurs in tropical regions.

Question 43

How does land use change impact the carbon cycle in terms of agriculture? - Carbon Cycle

Answer 43

Large areas of forest are deforested in order to make space for intensive farming to meet demand for food (eg. meat for the larger global middle class). This removes vast areas of carbon sinks and releases carbon into the atmosphere.

Question 44

Farming of what livestock/natural produce is particularly associated with changes to the carbon cycle? - Carbon Cycle

Answer 44

Cattle/Sheep, Soya, Palm Oil, Rice

Question 45

How does land use change impact the carbon cycle in terms of wetlands? - Carbon Cycle

Answer 45

Wetlands have been drained, leading to the destruction of a habitat that is a prominent carbon sink. The presence of water prevents the decomposition of organic matter and would lead to the sequestration of carbon over a long period. However, this cannot happen if wetlands are drained.

Question 46

How does land use change impact the carbon cycle in terms of urbanisation (CONCRETE AND CEMENT)? - Carbon Cycle

Answer 46

Urbanisation means land once covered in vegetation is concreted over to create an urban living environment. This removes soil to grow vegetation and, vitally, carbon sinks. Furthermore, cement production is a major emitter of CO2.

Question 47

What is urbanisation? - Carbon Cycle

Answer 47

Urbanisation is the process by which there is an increase in the proportion of a population living in urban areas.

Question 48

What is the Carbon Budget? Why is the carbon budget useful? - Carbon Cycle

Answer 48

The carbon budget is the difference between inputs and outputs of carbon in a subsystem.
The carbon budget helps us to understand how CO2 emissions contribute to changes in the Earth’s environment.

Question 49

What processes result in net increase of carbon in the atmosphere? - Carbon Cycle

Answer 49

Volcanic eruptions, fossil fuel combustion, respiration and ocean diffusion are processes which result in a net increase of atmospheric carbon.

Question 50

What processes result in the net decrease of carbon in the atmosphere? - Carbon Cycle

Answer 50

Photosynthesis, sequestration, weathering and ocean uptake result in a net decrease in atmospheric carbon.

Question 51

What process is responsible for the greatest flux of carbon? What is the Earth’s major store of Carbon? - Carbon Cycle

Answer 51

The major process of carbon flux is photosynthesis.

The largest store of Carbon in the Earth is the lithosphere (carbon stored in soils and rocks).

Question 52

How can the fluxes in the carbon cycle lead it to be described as a dynamic equilibrium? - Carbon Cycle

Answer 52

Inputs and outputs between the atmosphere and the Earth result in the Carbon cycle being in delicate balance in order to maintain the temperatures of the Earth.

Question 53

How have human activities threatened the dynamic equilibrium of the carbon cycle? - Carbon Cycle

Answer 53

Humans are emitting CO2 at a faster rate than it is being sequestered at, leading to an imbalance of carbon in sequestered form in relation to carbon in the atmosphere.

Question 54

How has change in carbon had an impact on the atmosphere in terms of cloud cover? - Carbon Cycle

Answer 54

The presence of dense vegetation increases respiration and photosynthesis, which in turn increases humidity and cloud cover. An increase in cloud cover increases the Earth’s albedo, cooling the Earth.

Question 55

How has oceanic photosynthesis had an impact on atmospheric carbon? - Carbon Cycle

Answer 55

Marine life (phytoplankton) requires CO2 to photosynthesise, removing carbon from the atmosphere. Phytoplankton release DMS, a substance which allows water droplets to condense on it. This increases precipitation and albedo, potentially causing cooling.

Question 56

What is DMS? How does it impact the Earth’s climactic conditions? - Carbon Cycle

Answer 56

DMS is a substance released by photosynthesising oceanic phytoplankton, which allows water droplets to condense on it, forming clouds. This increases the albedo of the Earth and causes cooling.

Question 57

How has volcanic activity had an impact on atmospheric carbon? What are the impacts of this? - Carbon Cycle

Answer 57

Volcanic eruptions release CO2 and particulate matter. This particulate matter absorbs solar infrared radiation, reducing warming. This is known as a VOLCANIC WINTER.

Question 58

How has change in carbon had an impact on land in terms of photosynthesis? - Carbon Cycle

Answer 58

Greater availability of CO2 in the atmosphere increases the amount of photosynthesis available to take place, meaning that a greater density of organic vegetation is present on the Earth’s surface.

Question 59

How has change in carbon had an impact on land in terms of biomes? (Tropics, Tundra and Permafrost) - Carbon Cycle

Answer 59

Increased warming is leading to the expansion of areas within the tropics, in addition to removing the tundra region. This has led to the melting of permafrost, releasing CO2 and methane which causes warming.

Question 60

How has change in carbon levels had an impact on land in terms of decomposition? - Carbon Cycle

Answer 60

Increased CO2 and warming global temperatures lead to increased decomposition of organic matter as this is helped by higher temperatures. Further releases CO2 into the atmosphere.

Question 61

How has change in carbon had an impact on oceans in terms of sea ice and of water volumes? - Carbon Cycle

Answer 61

Warmer oceans from higher global temperatures due to increased carbon have resulted in an increase in the ablation of sea ice. Furthermore, warmer water has a greater volume than colder water, which increases sea levels (THERMAL EXPANSION).

Question 62

How has change in carbon had an impact on oceans in terms of phytoplankton and photosynthesis? - Carbon Cycle

Answer 62

An increase in atmospheric carbon increases the rate of photosynthesis of marine plants such as phytoplankton. However, this is combatted by a decline in phytoplankton numbers due to warming temperatures.