The Carbon Cycle and Energy Security EQ1 Flashcards

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1
Q

What is the biogeochemical carbon cycle?

A

It is the short carbon cycle in which carbon moves from one store to another, driven by four key processes. It is a closed system meaning there are no external inputs or outputs.

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2
Q

What are the four main processes driving the biogeochemical carbon cycle?

A
  • photosynthesis
  • decomposition
  • combustion
  • respiration
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3
Q

What are the step in the biogeochemical cycle?

A
  1. Plants use atmospheric carbon dioxide to photosynthesis, allowing them to grow and produce organic matter full of carbon.
  2. This is organic matter eventually dies and falls to the ground as leaf litter.
  3. The leaf litter begins to decompose releasing the stored carbon back into the atmosphere, or into the soil.
  4. over a long period of time whent the build up of sediment in faster than the rate of decomposition, under great temperatures and pressures fossil fuels are formed.
  5. These fossil fuels and burned releasing all of the stored carbon into the atmosphere as carbon dioxide.
  6. Additionally, all animals are consistently respiring releasing carbon in to the atmosphere.
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4
Q

What is a fluxe?

A

The movement of organic carbon from one store to another, provide the motion in the carbon cycle.

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5
Q

What is a carbon store?

A

A carbon store is anything that stores carbon for a period of time. They can either function as sources (adding carbon form the atmosphere) or sinks (removing carbon from the atmosphere).

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6
Q

What units are used to measure carbon?

A

Petagrams (Pg) or Gigatonnes (Gt). A petagram/gigatonne is equal to a trillion kg or 1 billion tonnes.

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7
Q

What are the main types of carbon stores?

A

Atmosphere > as carbon dioxide and carbon compounds (CH4)
Hydrosphere (water) > dissolved carbon dioxide
Lithosphere (earths crust) > as carbonate in limestone, chalk and fossil fuels, or as pure carbon in diamonds and graphite
Biosphere > as carbon atoms in living and dead organisms

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8
Q

What are the main fluxes between stores in the carbon cycle?

A

Major fluxes are between
Oceans and atmosphere
Land (biological processes) and atmosphere
These fluxes vary in terms of flow but also in different timescales

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9
Q

What are anthropogenic causes?

A

Processes and actions associated with human activity.

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10
Q

What is the reservoir turnover?

A

The rate at which carbon enters and leaves a store.
Measured by
mass of carbon in any store / exchange fluxe

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11
Q

What is the geological carbon cycle?

A

This is the long carbon cycle, and is the process of storing carbon in underground geological formations such as rocks and sediment. It has a very large reservoir turnover rate of at least 100,000 years.

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12
Q

What is the key steps in the geological carbon cycle?

A
  1. Mechanical, chemical and biological weathering, beaks down the rocks insitu.
  2. Alongside decomposed organic matter are transported to oceans were they are deposited in the sea floor
  3. Over millions of years this sediment accumulates and sedimentation occurs, compression the sediment into sedimentary rock (limestone and slate)
  4. Deeper rock is under greater pressure and is converted to metamorphic rocks (marble)
  5. In some places the rocks will be taken back to the surface as molten magma or by tectonic uplift
  6. Volcano also play a part releasing carbon dioxide back into the atmosphere in an eruption this is known as outgassing
  7. The anthropogenic burning of fossil fuels releases a significant amount of carbon dioxide altering the equilibrium (releasing 35 Gt a year)
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13
Q

What is the carbon storage time and average Pg of Carbon in the crustal/terrestrial geological store?

A

Carbon storage time - Long term store, can be 100s of years to millennia
Consists of sedimentary rocks
100,000,000 PgC with fossil fuels adding an extra 4,000 PgC

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14
Q

What is the carbon storage time and average Pg of Carbon in the deep ocean store?

A

A long term store storing carbon for hundreds of year to millennia’s
Majority of the carbon is dissolved inorganic carbon at great depths.
38,000 PgC

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15
Q

What is the carbon storage time and average Pg of Carbon in the terrestrial soil store?

A

A short term store storing carbon for seconds to decades
This includes carbon stored as plant material (biomass), microorganisms breaks down the organic matter to CO2.
1,500 PgC

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16
Q

What is the carbon storage time and average Pg of Carbon in the surface oceanic store?

A

Short term store, storing carbon for seconds to decades
Includes fast exchange of carbon with the atmosphere though diffusion of carbon into the sea and biological process of plankton.
1,000 PgC

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17
Q

What is the carbon storage time and average Pg of Carbon in the atmosphere?

A

Short term store, storing carbon for seasons to decades.
Carbon is stored as CO2 and CH4 as greenhouse gases
560 PgC

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18
Q

What is the carbon storage time and average Pg of Carbon in the terrestrial ecosystem store?

A

A short term store, storing carbon for seconds to decades
Includes process such as photosynthesis converting the carbon into plant biomass and plant respiration
560 PgC

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19
Q

What is the definition of processes?

A

The physical mechanisms that drive the flux of material between stores.
E.g. weathering and sedimentation

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20
Q

How is the Himalayas an important carbon store?

A

The Himalayas is one of earths largest carbon stores. This is because the mountains started as ocean sediment rich in calcium carbonate (shells). The unfolding of the sediment and meant that the carbon contained has been weathered, eroded and transported back into the oceans.

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21
Q

How is carbon stored in fossil fuels?

A

When organic matter builds up faster than it can decay, layer of organic carbon become oil, gas and coal instead of shale. Under high heat and pressure.

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22
Q

What is oil and natural gas made from?

A

This is formed from the remains of tiny aquatic animals and plants.

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23
Q

What is coal made from?

A

Form the remains of trees, ferns and other plants.

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24
Q

Why are the two main geological carbon processes?

A
  • chemical weathering
  • volcanic outgassing
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25
Q

What is the steps of chemical weathering?

A
  1. Carbon dioxide in the atmosphere reacts with moisture to form weak carbonic acids and falls as precipitation
  2. Once the water reached the surface is reacts with surface minerals, dissolving them into its component ions
  3. The calcium ions are transported by rivers to the oceans which combine with bicarbonate ions forming calcium carbonate
  4. Deposition and burial turns the sediment into limestone
  5. Carbon is then released again in molten magma, tectonic uplifting or volcanic outgassing.
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26
Q

What is volcanic outgassing?

A

When pockets of carbon stored in the earths crust is released by volcanic eruption or tectonic activity. Occurs mainly along mid ocean ridges, subduction zones and magma hotspots.
They emit 0.15 - 0.26 Gt if CO2 annually.
E.g. Mt Pinatubo Philippines 1991

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27
Q

What is the thermohaline circulation?

A

The global system of surface and deep water ocean currents driven by temperature and salinity differences between oceans ‘ocean conveyor belt’.
It makes sure carbon is constantly being exchanged between the ocean and atmosphere.

28
Q

What are the three main types of carbon pump?

A
  • The physical pump
  • the biological pump
  • the carbonate pump
29
Q

What is the physical pump?

A

This is based on the ocean circulation of water moving carbon from polar water to warmers equatorial waters through downwelling, upwelling and the thermohaline circulation.

30
Q

What are the key steps in the physical carbon pump?

A
  1. Carbons enters the ocean in cold polar ares through the process of diffusion. (CO2 absorbed twice as fast in colder water)
  2. These waters are therefor rich in carbon and nutrients they are denser and sink taking carbon to the ocean depths.
  3. It then is moved by currents as part of the thermohaline circulation.
  4. It is returned to the surface by upwelling in warmer equatorial waters
31
Q

What is the biological carbon pump?

A

The biological carbon pump is the organic sequestering of carbon into oceans by phytoplankton.

32
Q

What are the steps in the biological carbon pump?

A
  1. Phytoplanktons can accumulate in an area of the ocean creating blooms.
  2. These blooms sequester carbon dioxide from the atmosphere to use in photosynthesis, converting the carbon into organic matter.
  3. These phytoplankton are eating by secondary consumers called zooplankton, which in turn release the carbon back into the atmosphere.
  4. Once dead the phytoplankton can accumulate on the ocean floor (marine snow), go through sedimentation and enter the geological carbon cycle.
33
Q

What the steps in the carbonate pump?

A
  1. The ocean naturally contains many dissolved chemicals (Chemical weathering), when CO2 dissolves in the ocean combines with water molecules and enters a series of chemical reactions producing soluble bicarbonate ions.
  2. These carbonate ions combine with calcium ions to form calcium carbonate.
  3. These calcium carbonate are used by Marien animals in exoskeletons and shells building.
  4. once these dies they sink the ocean floor and enter the slow carbon cycle.
34
Q

How does carbon travel through the food chain?

A
  1. Plants sequester carbon out of the atmosphere via photosynthesis, con=nverting it into organic matter such as glucose and starch
  2. When animals consume the primary producers, the carbon in the plant become part of their fats and protein.
  3. Some of the carbon is release via respiration, whilst others is disposed in waste and decomposition after they die. (carbon released into the soil)
35
Q

How does plant sequestor carbon?

A

Photosynthesis

36
Q

What time scales do carbon fluxes vary within an ecosystem?

A
  • Diurnally (sing during the day and source at night)
  • seasonally (in the Northern hemisphere, in the winter plant growth is minimised and decaying (leaf litter) atmospheric CO2 concentrations rise, during the spring when plant begins o grow concentration drops.
37
Q

What are the main stores of biological carbon?

A
  • tropical rainforests (organic matter, leaf litter and dead wood, which eventually decompose releasing nutrients and carbon which is quickly recycled)
  • Wetland and peat bogs (little decomposition due to high temperatures and pH meaning digestive enzymes denatured)
38
Q

How is biological carbon stored?

A
  • in living organisms as organic matter and molecules (glucose and carbohydrate)
  • in soils in the form of dead organic matter (eventually released into the atmosphere by decomposition)
39
Q

How much carbon does soil store?

A

Soil stores between 20%-30% of global carbon, twice as much as the atmosphere. Whether it sequesters carbon or emits it is based on local factors.

40
Q

What does the capacity of soil to store carbon depend on?

A

Whether soil sequesters carbon or emits it is based on local factors.
- climate
- vegetation cover
- soil type
- land use

41
Q

How does climate impact the capacity of soil to store carbon?

A

The climate dictates the amount of plant growth and detritivore activity.
- At higher temperatures decomposition happen more quickly and plant growth.
- In areas with high rainfall, increasing the soil potential to store carbon

42
Q

How does vegetation cover impact the capacity of soil to store carbon?

A

Vegetation cover affects the supply of dead organic matter, high vegetation cover increases ability to store carbon.

43
Q

How does soil type impact the capacity of soil to store carbon?

A

Areas with clay rich soils have a higher carbon content, as clay protects the carbon from decomposing.

44
Q

How does land use impact the capacity of soil to store carbon?

A
  • cultivation decrease the amount of stored carbon
  • soil disturbances such as ploughing have increased the rate of carbon loss (40-60 billion tonnes).
  • Indirectly humans are also responsible for climate change affecting vegetation, litter stores and flows.
45
Q

How is the carbon balance maintained in terrestrial ecosystems?

A

Carbon stores in the atmosphere, ecosystem and soils and in constant changes due to the abundance of processes such as plant productivity, microbial activity, geology and climate.

46
Q

Why is a balanced carbon cycle important?

A
  • Plays a key role in regulating the earths global temperature and climate by controlling atmospheric C02
  • The hydrological cycle (More extreme droughts an flooding)
  • Agriculture (dependant on climate and C02 concentration)
  • ecosystems (carbon factor is abiotic factor in an ecosystem (they are dependent on it))
47
Q

What is the natural greenhouse effect?

A

The natural greenhouse effect the natural temperature control system, which uses greenhouse gasses to keep the planet at a survivable temperature.

48
Q

What is the steps in the greenhouse effect?

A
  1. Then sun emits short wave UV radiation, which passes through the atmosphere and absorbed by the earths surface warming it
  2. The solar radiation is reflected back of the earths surface as long wave infrared radiation (albedo effect)
  3. Some of this IR radiation passes though the atmosphere as it lost in space, whilst others id re absorbed and re- emitted by greenhouse gases.
  4. This means the earths surfaces gaining more heat and IF is remitted again
49
Q

How does the increased amount of CO2 concentration affect temperature and precipitation?

A

Higher amount of carbon dioxide and other greenhouse gases (methane), enhance the greenhouse effect trapping and re-emitting more IR radiation warming the planet. The higher temperatures therefor change precipitation patterns.

50
Q

What is net primary productivity?

A

Thus is the rate at which plants turn carbon dioxide into biomass and organic matter. Help to measure the size of the carbon sink; higher the NPP the greater the carbon sink.

51
Q

What affects NPP?

A
  • Amount/density of vegetation
  • Concentration of CO2
  • nutrients availability
    (Maximum additionally growth rate of 20%)
52
Q

What is the role played by photosynthesis is the carbon cycle?

A

Photosynthesis by both ocean and terrestrial organisms play as essential role in keeping carbon dioxide levels relatively constant, helping to regulate earths mean temperature.

53
Q

What impact the rate of photosynthesis?

A

Photosynthesis varies spatially with NPP.

54
Q

Where is the highest rates if NPP on land?

A

Areas that are warm and wet areas have the highest NPP such as rainforests.
Mangroves > 1.5 metric tonnes of carbon annually. Soil composed of thick organic matter and high amounts of nutrients, lack of decomposition (high temp) mega high amounts of stored carbon as biomass
tropical rainforests > Carbon stored as biomass in trees and leaf litter. Decomposition of leaf litter releases nutrients and carbon dioxide which is quickly recycled.
Tundra soils > Soils in tundras are permanently frozen, meaning they store ancient carbon. Microbial activity only occurs in the surface level when it thaws.

55
Q

Where is the highest NPP in the ocean?

A

NPP is highest in shallow water, as phytoplankton can receive the highest amount of sunlight and nutrient input resulting in higher amount of photosynthesis.

56
Q

What determines soil health?

A

Soil health is determined by the amount go organic carbon stored in the soil.

57
Q

What influences soil health (inputs and outputs)?

A

The amount of stored soil carbon is determined by the balance between the inputs from plants/animals residue and nutrients and its outputs decomposition, soil erosion and use in plant and animal productivity.

58
Q

What is the importance of carbon in the soil?

A

Organic carbonic concentrated on the surface caller of the soil (easily eroded) it gives
- give soil moisture retention capacity
- structure and fertility
- determines the productive of ecosystems (provides air, water and nutrients fro micro-organism and plants to survive)

59
Q

What are the main quality’s of a healthy soil?

A
  • porous/retains moisture
  • crumbly
  • dark in colour
  • contains worms and organisms
60
Q

What is positive feedback?

A

When as change created an effect which in turn enhances the the original change.

61
Q

What is negative feedback?

A

When as changes create an effect which in turn reduces/diminishes the original change.

62
Q

What an example of positive feedback in climate change?

A
  • warmer air, hold more moisture (water vapour) which is a potent greenhouse gas
  • Increase in CO2 sequestering makes the ocean more acidic reducing the amount of C02 in can sequester increasing atmospheric carbon dioxide levels
  • Permafrost thawing due to rising temps increase atmospheric carbon dioxide
  • snow ice melt reducing the albedo effect more sun energy absorbed
63
Q

What are examples of negative feedback in climate change?

A
  • increase in temp and CO2 mean increased amount of plant growth and therefore increases in photosynthesis and carbon sink
  • Increase in temp means more evaporation and more cloud cover, more reflection of sunlight
64
Q

What implications does combustion of fossil fuel have on the carbon cycle?

A

Fossil fuel combustion is changing the balance of both carbon stores and fluxes. It has been burned at increasing rates since the Industrial revolution.

65
Q

What are the impacts of combustion of fossil fuels have on the climate?

A

Impacts are both global and regional
Global
- Rise is global mean temperature means more evaporation and more precipitation
- sudden shifts in weather patterns
- more extreme, intense and frequent hydrometeorological events (floods droughts)
- weaken thermohaline circulation
- rise in mean sea level
Regional
- change in local climate (wetter and drier)
- less precipitation falling as snow (more as rain)
- ström surges may increase

66
Q

What are the impact of combustion of fossil fuels have on ecosystems?

A

Ecosystem provide value due to the service they provide for the plants and human use. regulating the carbon and hydrological cycles
- marine organisms threatened with lower oxygen levels and ocean acidification
- rising temperature (may alter primary producers)
- flooding of low lysine coastal areas
- main impacts are on Artic and coral ecosystems
e.g. Habitat changes mean that 10% of land species will become extinct due to limited adaptability time

67
Q

What are the impact of combustion of fossil fuels have on the hydrological cycle?

A
  • increased evaporation will been more moisture circulating the air and more intense precipitation
  • change in precipitation type (more rain over snow)
  • earlier spring melt mega higher peaks in river flow
  • reduced sea ice, ice cap and glacial storage