4.3 Carbon cycling Flashcards

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1
Q

What are the spheres on Earth? What form of CO2 is taken up?

A

atmosphere (CO2), lithosphere (ground - detritus, fossil fuels), hydrosphere (bicarbonates and CaCO3 in shells, corals) and biosphere (living things - carbohydrates, proteins, lipids)

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2
Q

Give and example of a carbon cycle

A
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3
Q

Which processes determine the level of CO2?

A
  • Photosynthesis
  • Respiration
  • Decomposition – releases carbon products into the air or sediment when organic matter is recycled after death of an organism
  • Gaseous dissolution – the exchange of carbon gases between the ocean and atmosphere
  • Lithification – the compaction of carbon-containing sediments into fossils and rocks within the Earth’s crust (e.g. limestone)
  • Combustion
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4
Q

Explain how CO2 is converted into CaCO3 in oceans?

A
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5
Q

Define methanogens, where can they be found?

A

Methanogens are archaean microorganisms that produce methane (CH4) as a metabolic by-product in anaerobic conditions

  • Wetlands (e.g. swamps and marshes)
  • Marine sediments (e.g. in the mud of lake beds)
  • Digestive tract of ruminant animals (e.g. cows, sheep, goats)
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6
Q

Chemical equations of methane production by methanogens

A

Anaerobic digestion

  • Acetic acid → Methane and Carbon Dioxide (CH3COO– + H+ → CH4 + CO2)
  • Carbon Dioxide and Hydrogen → Methane and Water (CO2 + 4 H2 → CH4 + 2 H2O)
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7
Q

Whta happens to methane in atmospeher?

A

Its is oxidised to CO2

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8
Q

How are coal, fossil fuels and natural gas formed?

A
  • Decomposition: by saprotrophs (if oxygenated env) - in anaerobic conditions decomposition does not occur => peat (acidic) - compressed with heat and pressure -> impurities removed -> high C conc -> coal
  • Oil and natural gas - decay of amrine organisms - anoxic conditions prevent decomposition - _hydrocarbons forme_d - over million years into gas and oil - non-renewable
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9
Q

Sources of combustion

A
  1. Fossil fuels: human activity
  2. Biomass: organisms produce hydrocarbons as their mass - can be used to produce laternative fuel
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10
Q

Example of carbon cycle

A
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