The Carbon Cycle

Question 1

Photosynthesis

Answer 1

The process whereby plants use the light energy from the sun to produce carbohydrates in the form of glucose. This removes carbon from the atmosphere and allows vegetation to grow.

Question 2

Respiration

Answer 2

A chemical process that happens in all cells, which converts glucose into energy. Carbon is released back to the atmosphere but less than is absorbed for photosynthesis meaning that vegetation is naturally a carbon sink.

Question 3

Decomposition

Answer 3

The process where carbon from the bodies of dead organisms is returned to the air as carbon dioxide. Eg microorganisms decompose leaf litter and the carbon is returned to the atmosphere

Question 4

Combustion

Answer 4

The process where carbon is burned in the presence of oxygen and converted to energy, carbon dioxide and water eg wildfires or burning fossil fuels

Question 5

Sequestration

Answer 5

An umbrella term used to describe the long-term storage of carbon in plants, soils, rock formations and oceans

Question 6

Diffusion

Answer 6

The movement of carbon between the ocean and the atmosphere. Cold water can hold more carbon so during glacials there is more diffusion into the ocean.

Question 7

Weathering

Answer 7

The breakdown or decay of rocks in their original place at, or close to, the surface. Chemical weathering involves the absorption of carbon dioxide from the atmosphere, acidic rainwater then reacts with calcium in rocks to form calcium bicarbonate which is then buried and compacted and sequestered in the oceans.

Question 8

Burial and compaction

Answer 8

Where organic matter becomes buried and is then compressed by the overlying sediment

Question 9

Carbon budget

Answer 9

A way of using data to describe the amount of carbon that is stored and transferred within the carbon cycle

Question 10

Carbon sink

Answer 10

Anything that absorbs more carbon than it releases eg the ocean

Question 11

Carbon source

Answer 11

Anything that releases more carbon than it absorbs

Question 12

Mitigation

Answer 12

Any method used to reduce or prevent emission of greenhouse gases

Question 13

Carbon capture and storage (CCS)

Answer 13

The technological ‘capturing’ of carbon emitted from power stations. Atmospheric carbon dioxide is compressed into a liquid and is then pumped and stores several kilometres into the ground.

Question 14

Renewable energy

Answer 14

Energy generated from sources that can be renewed and used multiple times, eg hydroelectric power.

Question 15

Carbon farming

Answer 15

Where one type of crop is replaced by another that has greater productivity and can absorb more carbon dioxide from the atmosphere

Question 16

Hydrocarbons

Answer 16

Compounds of carbon and hydrogen which are the basis of fossil fuels such as oil and gas

Question 17

Lithosere

Answer 17

A vegetation succession that originates on a bare rocky surface. Bare rock will be colonised by lichens, followed by mosses and grass. Eventually, soil builds up allowing shrubs and trees to grow until climatic climax is reached.

Question 18

Seral stage

Answer 18

A stage within a sere

Question 19

Sere

Answer 19

A complete vegetation succession

Question 20

Vegetation succession

Answer 20

The sequence of changes that take place as plant life colonises bare rock, sand, water or salty areas

Question 21

Climatic Climax

Answer 21

The final stage of serial succession. Vegetation remains relatively unchanged
unless destroyed by an event such as fire or human interference.

Question 22

Humus

Answer 22

The organic component of soil, formed by the decomposition of leaves and
other plant material by soil microorganisms

Question 23

Milankovitch cycles

Answer 23

Changes in the shape earth’s orbit and tilt that cause glacial periods and interglacial periods. This is a long-term natural cause of climate change on Earth, it can cause changes to the carbon cycle as cooler oceans absorb more carbon and colder temperatures slow vegetation growth and decomposition.

Question 24

Enhanced greenhouse effect

Answer 24

Rising global temperatures due to greenhouse gases being put into the atmosphere because of human activities