Topic 6 - The Carbon Cycle And Energy Security EQ1

Question 1

Explain the stores of carbon and its importance?

Answer 1

• stores referred to as pools, stocks and reservoirs
• they are terrestrial, oceanic and atmospheric
• carbon provides major building blocks for all life on earth - regulates climate allowing for life

Question 2

explain what the geological carbon cycle is?

Answer 2

• natural cycle - moves carbon between land, oceans and atmospheres involving number of chemical reactions to create new stores
• equilibrium can be distrupted by major volcanic eruptions or natural climate changes

Question 3

Give 3 important natural stores and fluxes of carbon?

Answer 3

• terrestrial carbon, held in mantle is released into atsmpphere as carbon dioxide when volcanoes erupt (known as ‘out-gassing’)
• chemical weathering - carbon dioxide reacts with rainfall in atmosphere to produce weak acid (acid rain) which dissolves carbon dioxide-rich rocks releasing bicarbonates
• carbon in organic matter from plants,animal shells and skeletons sinks to ocean bed when they die, build up forming coal and chalk

Question 4

Explain how equilibrium is maintained in the geological carbon cycle?

Answer 4

• impact of emissions from volcanic eruptions sends extra CO2 into the atmosphere - leads to rising temps, increased evaporation and higher atmospheric moisture
• leads to acidic rain which weathers rocks creating bicarbonates which will eventually be deposited as carbon on the ocean floor
• chemical weathering process slowly rebalances the carbon cycle

Question 5

Explain the 4 key processes involved in the bio-geochemical carbon cycle?

Answer 5

photosynthesis - removing CO2 from the atmosphere to promote plant growth

respiration - releasing CO2 into the atmosphere as animals consume plant grow t and breathe

decomposition - breaking down organic matter and releasing CO2 into soils

combustion - of biomass and fossil fuels releases CO2 and greenhouse gases

Question 6

Explain what the bio-geochemical carbon cycle is?

Answer 6

• geological cycle referred to as bio-geochemical because biological and chemical processes determine how much of the available carbon on earth is stored or released at any one time
• living organisms play crucial role in maintaining the efficient running of the system
• 4 key processes continuously transfer carbon from one store to another

Question 7

Give and explain the 3 forms of carbon?

Answer 7

inorganic - found in rocks as bicarbonates and carbonates (largest store)

oragnic - found in plant material

gaseous - found as carbon dioxide methane and carbon monoxide

Question 8

What are fluxes - give 2 examples which differ?

Answer 8

The exchange of carbon between stores

• for example inorganic carbon is released by chemical weathering slowly
• fluxes between earths surface, plants and atmosphere are much faster (happen over months of seasons)

Question 9

Explain why there are variations in carbon fluxes?

Answer 9

Plants take carbon from the atmosphere through photosynthesis and release it by respiration - happens quickly and is controlled by sunlight, temperature and moisture

Dead organic materials in soil may retain carbon for years - some organic materials may become deeply buried and transform into sedimentary rocks - CO2 released when rocks are burned or used industrially (eg cement) - takes a very long time

Question 10

Explain how geographical patterns can impact fluxes of CO2?

Answer 10

• regional climates influence rates of photosynthesis and respiration
• CO2 fluxes vary with latitude - higher levels in northern hemisphere due to greater landmasses and temperature variations than in southern