Water and Carbon Cycles- Carbon Flows

Question 1

Define stores/stocks

Answer 1

The total amount of material of interest held within a part of the system

Question 2

Define fluxes

Answer 2

Measurements of the rate of flow of material between the stores (units are: mass per unit of time)

Question 3

Define processes

Answer 3

The physical mechanisms which drive the flux of material between stores eg. photosynthesis

Question 4

How does photosynthesis transfer carbon?

Answer 4

• transfers carbon stored in the atmosphere to biomass
• plants use energy from the Sun to change CO2 and water into glucose and oxygen
• carbon is passed through the food chain and released through respiration and decomposition

Question 5

How does respiration transfer carbon?

Answer 5

• transfers carbon from living organisms to the atmosphere

- plants and animals break down glucose for energy, releasing CO2 and methane in the process

Question 6

How does combustion transfer combustion?

Answer 6

• transfers carbon stored in living dead or decomposed biomass to the atmosphere by burning
• wildfires cause carbon flows

Question 7

How does decomposition transfer carbon?

Answer 7

• transfers carbon from dead biomass to the atmosphere and the soil
• after death bacteria and fungi break down organisms- CO2 and methane released
• some carbon is transferred to the soil in the form of humus

Question 8

How does ocean uptake and loss transfer carbon?

Answer 8

• CO2 directly dissolved from the atmosphere into the ocean
• also transferred to the oceans when it is taken up by organisms that live in them
• carbon is transferred to the atmosphere when carbon-rich water from deep in the oceans rises to the surface and releases CO2

Question 9

How does weathering transfer carbon?

Answer 9

• chemical weathering transfers carbon from the atmosphere to the hydrosphere and biosphere
• atmospheric carbon reacts with water vapour to form acid rain- when this falls onto rocks a chemical reaction dissolves the rocks
• resulting molecules washed into the sea where they react with CO2 to form calcium carbonate which is used by sea creatures

Question 10

How does sequestration transfer carbon?

Answer 10

• carbon from the atmosphere can be sequestered (captured and held) in sedimentary rocks or as fossil fuels
• rocks and fossil fuels form over millions of years when organisms die
• carbon is fossil fuels is sequestered until we burn them

Question 11

How does temperature affect the amount of CO2 dissolved?

Answer 11

There is a negative correlation between the temperature of the water and the amount of CO2 that can be dissolved

Question 12

Caron cycle of a tree

Answer 12

• tree takes in CO2 for photosynthesis
• allows tree to release energy and grow
• carbon is stored in the organic matter of the plant to make up its biomass
• some CO2 leaves plant as cells respire
• root cells that respire/die release the carbon stored in roots
• when tree dies the material decomposes which releases carbon into soil
• decomposes respire which release CO2 back into atmosphere

Question 13

Vegetation succession in the lithosere

Answer 13

1. Rock exposed for first time and exposed to weathering
2. Rock slowly broken down releasing carbon
3. Over time lichen and moss grow on bare rock and carbon exchange takes place
4. As organic matter is added to broken fragments of rock a soil develops
5. Over hundreds of years the plant species becomes more diverse (due to supply of carbon in soil)
6. Final stage involves environmental equilibrium (in response to climate). In the UK this is usually deciduous woodlands

Question 14

What carbon transfers are found in the lithosere?

Answer 14

• from rock to lichen/moss
• from decomposing vegetation to soil
• respiration and photosynthesis of plants to atmosphere
• animals eat carbon from plants