processes in carbon cycle

Question 1

how does photosynthesis affect carbon

Answer 1

• uses energy from sun to combine atmospheric CO2 and water to form carbohydrates for energy
• turns CO2 to O2

Question 2

respiration

Answer 2

takes O2 from atmosphere and changes it to Co2

Question 3

decomposition

Answer 3

plants and animals die and decompose as bacteria breaks down the dead organism which releases methane and CO2

Question 4

combustion

Answer 4

occurs when any organic material is reacted in the presence of oxygen to give off CO2

Question 5

burial and compaction

Answer 5

• organic matter is buried by sediments and becomes compacted
• corals absorb CO2 and convert it to calcium carbonate which is then compacted to make limestone

Question 6

carbon sequestration

Answer 6

• captures and held in sedimentary rocks or as fossil fuels until burned

Question 7

weathering

Answer 7

breakdown or decay of rocks in their original place (acid rain is mild carbonic acid)

Question 8

ocean uptake and loss

Answer 8

• CO2 is directly dissolved from the atmosphere into the ocean, its also transferred to ocean when its taken up by organism that live there
• carbon rich water deep in the oceans sometimes rises to surface and releases CO2 to atmosphere

Question 9

geological component of carbon transfer

Answer 9

where the carbon cycle interacts with the rock cycle in the processes of weathering, burial, subduction and volcanic eruptions

Question 10

natural ocean carbon pumps - who does it work?

Answer 10

Convection currents occur due to warmer waters being moved from tropics to polar regions. Here the water is cooled, becomes denser and sinks below. When colder waters return to the surface and warms again it loses co2 to the atmosphere. So vertical circulation means co2 is constantly transferred between ocean and atmosphere.

Question 11

what is biomass combustion

Answer 11

the burning of living and dead vegetation due to wildfires or for human use

Question 12

carbon cycle has different scales

Answer 12

• local - plants (within biosphere)
• sere - eg: deciduous woodland (terrestrial)
• continental - geological

Question 13

sere

Answer 13

a vegetation succession (sequence of changes) that relates to a specific environment

Question 14

example of vegetation succession (lithosere)

Answer 14

• rock exposed for first time after glacier melts
• vulnerable rock is weathered and releases CO2
• lichen and moss grow on bare rock
• carbon exchange occurs (photosynthesis/respiration)
• soil forms as more matter is added
• soil absorbs more carbon
• more plants species grow over time
• eventually becomes deciduous woodland

Question 15

volcanoes emit ? tonnes of CO2 each year compared to humans emitting ? tonnes from burning fossil fuels

Answer 15

volcanoes: 130-180tonnes
humans: 30 billion tonnes

Question 16

impact of colder temperatures on precipitation

Answer 16

cold water can hold more CO2 so there would be more chemical weathering

Question 17

impact of colder temperatures on decomposers

Answer 17

decomposers would be less effective so carbon transfer to the soil would be reduced

Question 18

impact of colder temperatures on ice

Answer 18

More water stored as ice means less is transferred to oceans. There would be less sediment transfer along rivers and less sediment build up on ocean floor.

Question 19

impact of colder temperatures on soil

Answer 19

soil would become frozen over vast areas so stops CO2 soil transfer

Question 20

impact of colder temperatures on biosphere

Answer 20

• less photosynthesis

- less respiration

Question 21

impact of warmer conditions

Answer 21

• more permafrost melting which releases previously trapped gas, methane and co2 are released so enhances greenhouse effect
• positive feedback destabilises system

Question 22

what is permafrost

Answer 22

Permafrost is soil, rock or sediment that is frozen for more than two consecutive years