global carbon cycle

Question 1

what does the global carbon cycle consist of and how is it connected?

Answer 1

number of stores and sinks connected by flows of carbon

Question 2

what are the principle stores?

Answer 2

atmosphere
the oceans
carbonate rocks
fossil fuels
plants and soils

Question 3

what is the biggest store?

Answer 3

carbonate rocks

Question 4

how much carbon is stored in carbonate rocks?

Answer 4

60 to 100 trillion tonnes

Question 5

what are the 2 strands to the carbon cycle?

Answer 5

fast carbon cycle
slow carbon cycle

Question 6

what is the slow carbon cycle?

Answer 6

the movement of carbon between the atmosphere, lithosphere and the oceans.

Question 7

how does the carbon move in the slow carbon cycle?

Answer 7

CO2 diffuses from the atmosphere to the oceans, where marine organisms make their shells and skeletons. when they die, the remains of these organisms sink to the ocean floor. They accumulate over millions of years and convert to carbon rich sedimentary rock due to heat and pressure. Then, sometimes they are subducted at plate boundaries, and are vented to the atmosphere in volcanic eruptions. Other rocks are exposed to the surface, and attacked by chemical weathering processes such as carbonation, forming an acid, which gets into streams, rivers, and oceans.

Question 8

how much carbon moves in the slow carbon cycle?

Answer 8

10-100 million tonnes/year

Question 9

what is the typical residence time for carbon held in sedimentary rocks?

Answer 9

150 million years

Question 10

how much carbon is released by the volcanic eruptions?

Answer 10

200 million tonnes

Question 11

how much quicker are transfers in the fast carbon cycle than the slow?

Answer 11

10-100x

Question 12

what are the main stores in the fast carbon cycle?

Answer 12

atmosphere
oceans
living organisms
soils

Question 13

what are the 2 key components to the fast carbon cycle?

Answer 13

plants
microscopic physoplankton

Question 14

how much carbon goes through the fast carbon cycle/ year?

Answer 14

1 billion to 100 billion tonnes / year

Question 15

how do plants remove carbon from the atmosphere?

Answer 15

they absorb CO2 from the atmosphere and combine it with water to make carbohydrates } photosynthesis
(fundamental to the food chain)

Question 16

what are 3 processes that result in the release of CO2 to the atmosphere?

Answer 16

respiration
decomposition
fires

Question 17

describe how carbon moves between the oceans and the atmosphere

Answer 17

atmospheric CO2 dissolves in the ocean surface waters, while oceans ventilate CO2 back to the atmosphere.

Question 18

how long does the exchange take between the atmosphere and the ocean?

Answer 18

carbon molecules are stored for 350 years by natural sequestration.

Question 19

what else is a very carbon dense area, where carbon is stored?

Answer 19

peat bogs

Question 20

What are the 6 processes involved in carbon exchange?

Answer 20

Precipitation
Photosynthesis
Weathering
Respiration
Decomposition
Combustion

Question 21

Explain how precipitation works in the carbon cycle

Answer 21

Atmospheric C02 dissolves in rainwater to form weak carbonic acid. This is natural process
However, rising concs of CO2 in the atmosphere due to anthropogenic emissions, have increased the acidity of the rainfall, meaning increased acidity of ocean surface water + harmful effects on marine life

Question 22

Explain how photosynthesis works in the carbon cycle

Answer 22

The flux of carbon from atmosphere - land plants - phytoplankton via photosynthesis is around 120 GT / year
Plants release CO2 to atmosphere during respiration which occurs while they use energy created by photosynthesis

Question 23

What is the photosynthesis word equation?

Answer 23

Carbon dioxide + water = glucose + oxygen

Question 24

What is the photosynthesis chemical equation?

Answer 24

6CO2 + 6H2O → C6H12O6 + 6O2

Question 25

Explain how weathering works in the carbon cycle?

Answer 25

Most weathering involves rainwater which contains dissolved CO2, from soils and atmosphere. As rainwater is a weak carbonic acid, it dissolves limestone and chalk through carbonation which releases carbon to rivers oceans and atmosphere
Biological weathering such as chelation contribute to rock breakdown - rainwater and dead decaying organic material attack rock mineral

Question 26

How much carbon does weathering transfer to the atmosphere and oceans / year?

Answer 26

0.3 billion tonnes / year

Question 27

Explain respiration’s effect on the carbon cycle

Answer 27

Emits carbon

Question 28

Explain effect of decomposition on the carbon cycle

Answer 28

Decomposed organisms eg fungi + bacteria break down dead organic matter, realising carbon to the atmosphere and nutrients to the soil
Rates depend on climatic condition

Question 29

Explain effect of combustion on carbon cycle

Answer 29

Organic material burns in the presence of carbon
Acts as natural fuel in wildfires…
Also results from human activities
Releases carbon to atmosphere

Question 30

What is downwelling?

Answer 30

When surface ocean currents transport water and dissolved CO2 polewards, where or cold, becomes more dense and sinks

Question 31

What is downwelling known as?

Answer 31

Physical/ inorganic pump

Question 32

What is upwelling?

Answer 32

Deep ocean currents transport carbon to areas of upwelling
There, cold, carbon rich water rises to the ocean surface and CO2 diffuses back into the atmosphere

Question 33

What is the biological/ organic pump?

Answer 33

Carbon exchanged between oceans and atmosphere through actions of marine organisms

Question 34

Where does downwelling occur?

Answer 34

Cold areas
Iceland, greenlands, North Atlantic

Question 35

Where does upwelling occur?

Answer 35

Warmer areas
Equator