The Carbon Cycle

Question 1

How is carbon stored in the lithosphere and how much?

Answer 1

In sedimentary rocks and fossils.
99.9% of carbon on earth stored in lithosphere.

Question 2

How is carbon stored in the atmosphere and how much?

Answer 2

As carbon dioxide and methane.
0.001% of earths carbon stored in atmosphere.

Question 3

How is carbon stored in the biosphere and how much?

Answer 3

In the tissue of living organisms.
0.04% of Earths carbon.

Question 4

How is carbon stored in the cryosphere and how much?

Answer 4

In the soil in areas of permafrost where decomposing animals have frozen into the ground.
Less than 0.01% of Earths carbon.

Question 5

How is carbon stored in the hydrosphere and how much?

Answer 5

Carbon dioxide is dissolved into rivers, lakes and oceans.
Often deep in there ocean due to decaying animals.
0.04% of carbon on Earth.

Question 6

What type of system is the carbon cycle?

Answer 6

Closed.

Question 7

Describe photosynthesis as a flow in the carbon cycle.

Answer 7

Transfers carbon from the atmosphere to biomass.
Plants use photosynthesis to grow and is then passed on through the food chain and is released through respiration and decomposition.

Question 8

How is respiration a flow of the carbon cycle?

Answer 8

Respiration transfers carbon from living organisms to the atmosphere.
Animals release carbon dioxide and methane when they respire.

Question 9

How is combustion a flow of the carbon cycle?

Answer 9

Transfers carbon from living or decomposing biomass to the atmosphere by burning.
An example would be wildfires which cause a strong carbon flow.

Question 10

How is decomposition a flow in the carbon cycle?

Answer 10

Transfers carbon from dead biomass to the atmosphere and the soil.
Bacteria and fungi break organism down releasing CO2 and methane.
Can also transfer carbon into the soil forming hummus.

Question 11

How is ocean uptake/loss a flow in the carbon cycle?

Answer 11

Uptake: Carbon dioxide dissolved into the sea from the atmosphere and taken up by organisms (plankton).
Loss: Carbon is also released from the ocean into the atmosphere when carbon rich water rises to the surface.

Question 12

How is weathering a flow in the carbon cycle?

Answer 12

Chemical weathering transfers carbon from the atmosphere to the hydrosphere and biosphere.
Atmospheric carbon reacts with water vapour to form acid rain.
If it is washed into the sea it will react with carbon dioxide in the water to form calcium carbonate which is used by sea creatures to make shells.

Question 13

What is sequestration?

Answer 13

When carbon is captured and held in sedimentary rocks or as fossil fuels when dead animal and plant material is compacted on the ocean floor.

Question 14

How is sequestration a flow in the carbon cycle?

Answer 14

Carbon from the atmosphere sequestered in sedimentary rocks or as fossil fuels until we burn them.

Question 15

Which of the flows of carbon occur quickly?

Answer 15

Photosynthesis, respiration, combustion and decomposition

Question 16

Which flow of carbon takes the longest?

Answer 16

Sequestration, it can take millions of years.

Question 17

How can wildfires affect the carbon cycle?

Answer 17

Wildfires rapidly transfer large amounts of carbon from biomass into the atmosphere.
Lots of vegetation also means less photosynthesis occurs = less carbon removed from the atmosphere.

Question 18

How can volcanoes affect the carbon cycle?

Answer 18

Carbon is stored within the earth in magma and is released during eruptions and enters the atmosphere.

Question 19

What are the four human causes of change in the carbon cycle?

Answer 19

-Hydrocarbon extraction
-Deforestation
-Land use changes
-Farming practices

Question 20

How does hydrocarbon extraction change the carbon cycle?

Answer 20

Extracting and combusting fossil fuels that have been sequestered for thousands of years releases carbon dioxide into the atmosphere.

Question 21

How does deforestation affect the carbon cycle?

Answer 21

Forests cleared for logging or agriculture and reduces the size of the carbon store.
Often forest is burned releasing a large and rapid flow of carbon into the atmosphere.

Question 22

How do farming practices affect the carbon cycle?

Answer 22

-Animals release methane when they respire and digest food.
-Ploughing released carbon stored in the soil.
-Population increase means food production has increased, as a result, carbon emissions from farming have increased.

Question 23

How has land use changes affected the carbon cycle?

Answer 23

-Vegetation is removed to create space for buildings reducing the carbon store in the biosphere.
-Concrete production releases lots of carbon dioxide and is used when urban areas expand.

Question 24

What is the carbon budget?

Answer 24

The balance between carbon inputs and outputs in a subsystem.

Question 25

How does the carbon cycle affect the atmosphere and climate?

Answer 25

The amount of gases in the atmosphere.
Greenhouse gases are collected and trap the suns energy. This makes the world warm up (global warming).
Changes in temperature across the globe will affect other aspects of climate (more intense storms).

Question 26

How does the carbon cycle affect the land?

Answer 26

The carbon cycle allows plants to grow and photosynthesise.
If the world heats up carbon stored in the soil under permafrost will be released into the atmosphere.
Higher temperatures also increase the frequency of wildfires.

Question 27

How does the carbon cycle affect the oceans?

Answer 27

Carbon dioxide is dissolved directly into the oceans from the atmosphere and is used to by organisms to photosynthesise (seaweed) and to form shells.
Increasing of carbon in the atmosphere = increase in acidity affecting marine life (phytoplankton).
-Warmer waters are less able to dissolve CO2. As temperature rises the amount of carbon dissolved by the sea decreases.

Question 28

What does the carbon budget determine?

Answer 28

Whether it acts as a carbon source or a carbon sink.

Question 29

What is a carbon source?

Answer 29

A subsystem that releases more carbon than it absorbs.

Question 30

What is a carbon sink?

Answer 30

A subsystem that absorbs more carbon than it releases.