Flux table carbon cycle

Question 1

What is the process of diffusion?

Answer 1

Carbon dioxide diffuses from the atmosphere to water into plants

Carbon dioxide also diffuses from the atmosphere to the ocean.

Question 2

What are the oceans 2 carbon cycle ‘pump’ mechanisms referred to as?

Answer 2

Physical pump and Biological pump

Question 3

Describe the physical pump

Answer 3

• CO2 from atmosphere to ocean by diffusion
• Carbon dioxide dissolved in the surface of the ocean can be transferred to the deep ocean in areas where cold dense surface waters sink.
• This ‘downwelling’ carries carbon molecules to great depths where they may remain for centuries.
• When cold water returns to the surface and warms up again it loses carbon dioxide to the atmosphere.

Question 4

Describe the biological pump

Answer 4

• These move carbon dioxide from the ocean surface to marine plants called phytoplankton through photosynthesis
• This effectively converts carbon dioxide into food for zooplantic (microscopic animals) and their predators.
• Most of the carbon dioxide taken up by phytoplankton is recycled near the surface. About 30% sinks into deeper waters before being converted back into carbon dioxide by marine bacteria.

Question 5

How long does diffusion take?

Answer 5

Seconds

Question 6

What is photosynthesis

Answer 6

Plants use energy from sunlight to combine CO2 from the atmosphere with water from the soil to create carbohydrates.
In this way CO2 is removed from the atmosphere and stored in the structure of plants.

Question 7

Photosynthesis equation

Answer 7

Carbon Dioxide + Water → Light Energy → Oxygen + Glucose

Question 8

Explain photosynthesis in marine plants

Answer 8

Higher amounts of carbon dioxide are removed from the atmosphere into the oceanic biological pump.
Removing greenhouse gas molecules from the atmosphere mitigates the warming effect of CO2 fossil fuel emissions

Higher amounts of carbon drawn into the biological pump eventually move down into deep ocean currents and sediments.
Carbon stored in deep ocean currents is there for time scales of hundreds to thousands of years.

The carbon that makes its way to sea floor sediments is stored for time scales of millions to billions of years.

Question 9

How much of atmospheric carbon dioxide do global forest cycles make up for?

Answer 9

Photosynthesis in global forest cycles account for approximately one-twelfth of atmospheric carbon dioxide every year, accounting for about 50% of terrestrial (land based) photosynthesis.

Question 10

How long does photosynthesis take?

Answer 10

Seconds

Question 11

What is respiration?

Answer 11

• happens in all cells - common in plants and animals
• takes oxygen from the atmosphere and replaces it with carbon dioxide

Question 12

How long does respiration take?

Answer 12

Seconds

Question 13

Explain consumption in animals as a carbon flux

Answer 13

Animals feed on plants and other animals. Carbon is passed along the food chain.

Question 14

Explain consumption in marine animals as a carbon flux

Answer 14

Phytoplankton in the ocean is consumed by other marine organisms and carbon is passed long the food chain by fish and larger sea animals as they consume one another.

Question 15

How long does consumption take

Answer 15

Minutes hours

Question 16

Decomposition as a carbon flux

Answer 16

When organisms die they are consumed by decomposers such as bacteria, fungi and earthworms. This process of decomposition results in carbon from their bodies being returned to the atmosphere as carbon dioxide. Some carbon is also returned to the soil.

Question 17

Decomposition as a carbon flux - water

Answer 17

In oceans when organisms die, their dead cells and shells sink into deep water. Decay releases carbon dioxide into this deep water.

Question 18

How long does decomposition take?

Answer 18

Hours/days

Question 19

Shell and coral formation as a carbon flux

Answer 19

In oceans some carbon gets incorporated into marine organisms as structural calcium carbonate shells and coral skeletons.
When oceanic organism die shells and sinks to the bottom, where it forms a layer of carbon rich sediment. They are eventually lithified (turned into rock). This can lock up carbon for millions of years.

Question 20

How long does shell and coral formation last?

Answer 20

Millennia

Question 21

Fossilisation as a carbon flux - ocean

Answer 21

Over millions of years chemical and physical processes may turn the carbon rich sediment at the bottom of the ocean into sedimentary rocks (chalk and limestone) This is known as lithification. This can lock up carbon for millions of years.

Question 22

Fossilisation as a carbon flux - land

Answer 22

Partial decomposed organic matter from past geological eras converted into coal, oil and gas

Question 23

How long does fossilisation take?

Answer 23

Millennia

Question 24

Explain combustion

Answer 24

When organic material is burned in the presence of oxygen it gives off carbon dioxide, energy and water. The carbon dioxide is released into the atmosphere, returning carbon that might have been stored in rocks for millions of years.

Question 25

Industrial revolution affect on carbon emissions

Answer 25

Since the start of the industrial revolution carbon dioxide has been released at an increasing rate by the burning of fossil fuels and biomass (naturally occurring wildfires as well as human induced burning). These fossil fuels contain carbon that was captured by living organisms over periods of millions of years and have been stored within the Earth‘s crust.

Question 26

How much carbon do fires release per year?

Answer 26

Every year fires release more than a billion tonnes of carbon into the atmosphere as carbon dioxide.

Question 27

How long does combustion take?

Answer 27

Seconds

Question 28

Explain volcanic activity as a carbon flux

Answer 28

Huge volumes of stored carbon in sedimentary rocks are on the move constantly (albeit at extremely slow rates) through the geological process of tectonic plate movement.
Some carbon is eventually released into the atmosphere by volcanic eruptions, as CO2 is released form melted rocks when subduction occurs at plate boundaries.

Question 29

How long does volcanic activity take?

Answer 29

Hours / days

Question 30

Explain methane formation as a carbon flux

Answer 30

Organic matter held under water is metabolised by methane producing bacteria
Methane accumulates in the ground in porous rocks or underwater, but may diffuse into the atmosphere
In air and light methane is oxidised to CO2 and water.

Question 31

How long does methane formation take?

Answer 31

Minutes

Question 32

Explain how weathering is a carbon flux

Answer 32

Weathering involves the breakdown of rocks in situ (their original place). Water is the key medium for chemical weathering. When carbon dioxide is absorbed by rainwater it forms a mild carbonic acid. This reacts with calcium carbonate in chalk and limestone, forming calcium bicarbonate which is soluble and removed by percolating water.

Question 33

How much carbon is transferred to the atmosphere by weathering per year?

Answer 33

Globally, some 0.3 billion tonnes of carbon are transferred from rocks to the atmosphere and oceans each year by chemical weathering.

Question 34

Weathering - water - carbon flux explanation

Answer 34

Calcium bicarbonate can be transferred by overland flow, throughflow or groundwater flow into river where it becomes part of the solute load

Question 35

How long does chemical weathering take?

Answer 35

Years

Question 36

Carbon sequestration explanation

Answer 36

This is an umbrella term used to describe the transfer of carbon from the atmosphere to other stores for long term storage. Sequestration is both a natural process and a human process;

Question 37

Natural carbon sequestration explained

Answer 37

The natural capture and storage of carbon dioxide from the atmosphere by physical or biological processes such as photosynthesis (see diagram below). This occurs naturally but can be enhanced through land management practices that maximise the amount of carbon that remains stored in soil and in plants for the long term.

Question 38

Human carbon sequestration explained

Answer 38

CO2 captured at source e.g. power plants and then injected in liquid form into underground stores such as coal beds or depleted gas and oil reserves. This is experimental at the moment.

Question 39

How long does natural carbon sequestration take?

Answer 39

Seconds