Topic 6: The Carbon Cycle and Energy Security

Question 1

carbon sequestration

Answer 1

the removal and storage of carbon from the atmosphere, usually in oceans, forests and soils through photosynthesis

Question 2

photosynthesis

Answer 2

the use of energy from sunlight to produce nutrients from carbon dioxide and water

Question 3

natural greenhouse effect

Answer 3

the warming of the atmosphere as gases such as CO₂, CH₄ and water vapour absorb heat energy radiated from the Earth

Question 4

enhanced greenhouse effect

Answer 4

the increase in the natural greenhouse effect, said to be caused by human activities that increase the quanitity of greenhouse gases in the Earth’s atmosphere

Question 5

tonnes of oil equivalent

Answer 5

a unit designed to include all forms of energy by comparing them with oil in terms of heat output - it measures each type of energy by calculating the amount of heat obtained by burning one tonne, and then converting it to however much oil would be required to produce an equivalent amount of energy

Question 6

energy security

Answer 6

being able to access reliable and affordable sources of energy which may be domestic, but could also include energy sources from ‘friendly’ countries

Question 7

energy pathway

Answer 7

the flow of energy between a producer and a consumer, and how it reaches the consumer, e.g. pipeline, transmission lines, ship, rail

Question 8

transit state

Answer 8

a country or state through which energy flows on its way from producer to consumer

Question 9

bio-geochemical carbon cycle

Answer 9

the continuous transfer of carbon from one store to another, through the processes of photosynthesis, respiration, decomposition and combustion

Question 10

biological carbon pump

Answer 10

where phytoplankton in the oceans sequester carbon dioxide through the process of photosynthesis, pumping it out of the atmosphere and into the ocean store

Question 11

biological decomposers

Answer 11

organisms such as insects, worms and bacteria which feed on dead plants, animals and waste

Question 12

biologically derived carbon

Answer 12

carbon which is stored in shale, coal and other sedimentary rocks

Question 13

carbon capture and storage (CCS)

Answer 13

the technological ‘capturing’ of carbon emitted from power stations

Question 14

carbon fixation

Answer 14

turns gaseous carbon (CO₂) into living organic compounds that grow

Question 15

energy mix

Answer 15

the range and combination of sources required to supply a country with energy

Question 16

geological carbon

Answer 16

carbon which results from the formation of sedimentary carbonate rocks (limestone and chalk) in the oceans

Question 17

ocean acidification

Answer 17

the process of the ocean’s pH decreasing as the level of CO₂ in the ocean increases

Question 18

long-term slow geological cycle

Answer 18

• volcanic out-gassing, releases terrestrial carbon into atmosphere as carbon dioxide
• carbon dioxide combines with rainfall to produce weak carbonic acid/acid rain, dissolves carbon-rich silicate rocks, releases bicarbonates (chemical weathering)
• rivers transport weathered carbon/calcium sediments to oceans (deposition)
• carbon in plants and animal shells/skeletons sinks to ocean bed when they die, strata of coal/chalk/limestone build up
• carbon-rich rocks subducted along plate boundaries, intense heating creates metamorphic rocks and this process releases carbon dioxide

Question 19

short-term fast biological cycle

Answer 19

• phytoplankton sequester atmospheric carbon during photosynthesis in surface ocean waters
• carbonate shells/tests move into the deep ocean water through the carbonate pump and action of the thermohaline circulation
• terrestrial primary producers sequester carbon during photosynthesis
• some of this carbon is returned to the atmosphere during respiration by consumer organisms
• biological carbon can be stored as dead organic matter in soils, or returned to the atmosphere via biological decomposition over several years