WCC: Carbon Cycle - Factors Driving Change in the Magnitude of Carbon Stores Over Time

Question 1

Chemical equation for photosynthesis

Answer 1

6CO2 + H2O -> 6O2 + C6H12O6

Question 2

Chemical equation for respiration

Answer 2

C6H12O6 + 6O2 -> 6CO2 + 6H2O

Question 3

Describe a lithosere

Answer 3

1. Exposed rock is vulnerable to weathering
2. Weathering releases carbon, often dissolved in water
3. Lichen and mosses grow on the bare rock and a carbon exchange starts to take place
4. As organic matter is added a soil develops that can support a wider range of plants
5. Wildlife becomes abundant
6. Climatic climax reached

Question 4

NEW

Answer 4

NEW

Question 5

What have been the maximum and minimum amounts of carbon stored in the atmosphere throughout history? When did they occur?

Answer 5

Atmospheric CO2 possibly reached over 7,000 ppm in the Cambarian period around 500 million years ago. Its lowest concentration has been over the last 2 million years during the Quaternary glaciation when it sank to about 180 ppm.

Question 6

Where is atmospheric carbon measured on Earth?

Answer 6

At the Mauna Loa Observatory on Hawaii

Question 7

How has the magnitude of carbon stored in the atmosphere changed since the Industrial Revolution?

Answer 7

Global annual mean concentration of CO2 has increases from 280 ppm in 1958 to 400 ppm in 2015 - a percentage increase of 143% in 30 years

Question 8

The present concentration of atmospheric CO2 is higher than is has been for how many years?

Answer 8

At least 800,000 years, buts it’s likely the highest that its been in the past 20 million years.

Question 9

What sources is the recent rise in atmospheric CO2 being attributed to?

Answer 9

Anthropogenic sources, mainly burning fossil fuels and deforestation

Question 10

What is the name of the graph showing changing concentration of atmospheric CO2?

Answer 10

the Keeling curve

Question 11

As well as readings from MLO, name another method of measuring atmospheric CO2 over time. How does it work?

Answer 11

Studying the CO2 in trapped ice cores from Antarctica and Greenland can give a proxy measure of the CO2 in the atmosphere at the time is was laid down, allowing the change over time to be seen

Question 12

When did the daily average of atmospheric CO2 at MLO first exceed 400 ppm?

Answer 12

May 2013

Question 13

At what rate is atmospheric CO2 currently rising?

Answer 13

2 ppm/year

Question 14

How is the rate of increase of atmospheric CO2 changing?

Answer 14

It is accelerating

Question 15

Describe how the magnitude of soil carbon stores can change over time.

Answer 15

Carbon can remain in soils for hundreds of years, however deforestation, land use change and soil erosion can release the stored carbon very rapidly

Question 16

How is carbon uptake from vegetation changing over space?

Answer 16

Carbon uptake is increasing in the middle and high latitudes of the northern hemisphere, but decreasing in the tropics and southern hemisphere

Question 17

What is a major reason why less carbon is being absorbed in the tropics and southern hemispere?

Answer 17

Drought

Question 18

What is photosynthesis?

Answer 18

The process whereby organisms use light energy from the sun to combine CO2 from the atmosphere with water to form carbohydrates which store energy.

Question 19

Word equation for photosynthesis

Answer 19

Carbon dioxide + water + sunlight -> glucose + oxygen

Question 20

Which organisms photosynthesise?

Answer 20

Terrestrial plants
Phytoplankton
Photosynthetic algae
Bacteria

Question 21

What is respiration?

Answer 21

A chemical process that occurs in cells where oxygen from the atmosphere is used to convert glucose into energy to be used in an organism’s life functions

Question 22

What are the by-products of respiration?

Answer 22

Carbon dioxide and water

Question 23

Which organisms respire?

Answer 23

All organisms - animals, plants, photosynthetic algae and bacteria

Question 24

Is there a balance between photosynthesis and respiration? How does this impact the carbon cycle?

Answer 24

No as not all organic matter is used in respiration. This means over time photosynthesis removes more CO2 from the atmosphere than respiration releases.

Question 25

Word equation for respiration

Answer 25

Oxygen + glucose -> energy + water + carbon dioxide

Question 26

What is decomposition?

Answer 26

Physical, chemical and biological mechanisms transforming organic matter into increasingly stable forms

Question 27

What are the biological mechanisms resulting in decomposition of organisms?

Answer 27

Feeding and digestion aided by the catalytic effect of enzymes

Question 28

Why is decomposition important in the carbon cycle?

Answer 28

It ensures carbon can be continually recycled into the soil and made available for life

Question 29

What carries out the decomposition process?

Answer 29

Decomposers

Question 30

What do decomposers do?

Answer 30

Break down the cells and tissues in dead organisms into large biomolecules and then break those down into smaller molecules and individual atoms

Question 31

Give 3 examples of decomposers.

Answer 31

Earthworms Fungi Bacteria

Question 32

Where is the carbon from decomposed material transferred to?

Answer 32

The atmosphere and soil

Question 33

What is combustion?

Answer 33

The burning of organic material is the presence of oxygen to give off CO2, water and energy

Question 34

If an organic material which contains elements as well as carbon, hydrogen and oxygen is combusted, what will form and why?

Answer 34

A variety of pollutant molecules such as sulphur dioxides and nitrogen oxides will form as the other elements will ultimately combine with oxygen

Question 35

What is carbon sequestration?

Answer 35

The transfer of carbon from the atmosphere to plants, soils, rock formations and oceans

Question 36

Name 8 transfers driving change in the magnitude of carbon stores.

Answer 36

``` Photosynthesis Respiration Decomposition Combustion Burial and compaction Carbon sequestration Weathering Oceanic carbon pumps ```

Question 37

What is burial and compaction?

Answer 37

Where organic matter is buried by sediments and becomes compacted

Question 38

What can the burial and compaction of organic matter form over time?

Answer 38

Hydrocarbons such as coal and oil

Question 39

Give an example to illustrate how burial and compaction can transfer carbon from one store to another

Answer 39

Corals and shelled organisms take up CO2 from the water and convert it into calcium carbonate to build their shells. When they die the shells accumulate on the seabed. Some of the carbonate dissolves, releasing CO2. The rest becomes compacted to form limestone, storing carbon for millions of years.

Question 40

What is weathering?

Answer 40

The breakdown or decay of rocks in situ

Question 41

How does weathering act as a transfer in the carbon cycle?

Answer 41

When CO2 is absorbed by rainwater it forms carbonic acid. This slowly dissolves carbonate rocks with the carbon being held in solution. Dissolved carbon moves through runoff to the oceans.

Question 42

Which soil carbon stores are affected by weathering?

Answer 42

Soil Peat Sedimentary rocks

Question 43

Where does carbon transferred through weathering end up and how does it get there?

Answer 43

The oceans through runoff

Question 44

What is the oceanic carbon pump?

Answer 44

Where carbon in the surface waters of the ocean sinks to the bottom, transferring carbon from the upper layers to the lower layers of the ocean

Question 45

What is a greenhouse gas?

Answer 45

Any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere.

Question 46

What is the most important transfer of CO2 in the oceans?

Answer 46

Vertical deep mixing

Question 47

What is vertical deep mixing?

Answer 47

The transfer of surface water into the deep ocean and back again.

Question 48

Explain how the oceanic carbon pump acts as a transfer in the carbon cycle.

Answer 48

It carries carbon from the upper layers of the ocean and the atmosphere to the lower layers of the ocean and the lithosphere

Question 49

Describe the correlation between water temperatures and the amount of CO2 that can be dissolved

Answer 49

Negative - colder waters can hold more dissolved CO2

Question 50

Explain the process of vertical deep mixing.

Answer 50

Warm water in oceanic surface currents is carried from the warm tropics to the cold polar regions. It cools, allowing it to store more dissolved CO2 and making it dense enough to sink below the surface layer. Upwelling can bring the cold water back to the surface where it will warm up and release some of its CO2 to the atmosphere.

Question 51

What is a sere?

Answer 51

A vegetation succession that relates to a specific environment

Question 52

What is a vegetation succession?

Answer 52

The development and associated changes in a plant community through time

Question 53

What is a seral stage?

Answer 53

A stage in a vegetation succession

Question 54

Name 4 seres

Answer 54

Lithosere Hydrosere Halosere Psammosere

Question 55

What is a lithosere?

Answer 55

Vegetation succession on bare rock

Question 56

What is a hydrosere?

Answer 56

Vegetation succession in water e.g a freshwater pond

Question 57

What is a halosere?

Answer 57

Vegetation succession in saline conditions e.g coastal salt marsh

Question 58

What is a psammosere?

Answer 58

Vegetation succession in coastal sand e.g sand dunes

Question 59

What happens to the carbon stored in permafrost if it melts?

Answer 59

Is it converted into CO2, CH4, and dissolved organic carbon and transferred to the atmosphere and hydrosphere

Question 60

What are the 2 primary types of carbon sequestration?

Answer 60

Geologic sequestration | Terrestrial or biologic sequestration

Question 61

What is geological carbon sequestration?

Answer 61

Where CO2 is captured at its source and then injected in liquid form into underground stores

Question 62

Give 4 underground stores that can be used for geological sequestration.

Answer 62

Depleted oil and gas reservoirs Uneconomic coal seams Deep salt formations Deep ocean

Question 63

Why is the ocean capable of absorbing more carbon than terrestrial systems?

Answer 63

It's bigger

Question 64

What is terrestrial or biological carbon sequestration?

Answer 64

The use of plants to capture CO2 from the atmosphere and then to store is as carbon in stems, roots and soil

Question 65

Give 3 disadvantages with terrestrial carbon sequestration.

Answer 65

- A forest planted to capture carbon might lose carbon back to the atmosphere in the event of a fire or disease - Land-based sequestration plantations are slow growing and require active monitoring and magaement - The carbon within the systems is never permanently removed from the atmosphere

Question 66

What is the aim of terrestrial carbon sequestration?

Answer 66

To develop a set of land management practices that maximises the amount of carbon stored in the soil and plant material in the long term

Question 67

Explain the main advantage of oceanic carbon sequestration.

Answer 67

The sequestered carbon is sunk within weeks or months of being captured, but once in the deep ocean it is in a circulation system measured in thousands of years.

Question 68

What is soil respiration?

Answer 68

The respiration of bacteria in the soil during decomposition, releasing CO2 into the atmosphere