Carbon and Water cycles Flashcards
Main stores in water cycle
- Hydrosphere (96.5%)
- Cryosphere (1.7%)
- Lithosphere (1.7%)
- Atmosphere (0.001%)
Flows or transfers in water cycle
- Precipitation
- Evaporation
- Condensation
- Sublimation (change of state)
- Interception (stored on leaves)
- Overland flow
- Infiltration (through soil)
- Through flow (soil to river)
- Percolation (through rocks)
- Groundwater flow
Discharge equation
Discharge (m3 per sec) = cross-sectional area (m2) x velocity (metres per second)
Human activities affecting change in the water cycle
1) Land use change
- Urbanisation replaces vegetated ground with tarmac
2) Farming practices
- Farmers are able to control the local water cycle through irrigation or land drainage
6 carbon stores (size order)
- Marine sediment (100,000 bil of metric tons)
- Ocean (38,000)
- Fossil fuel deposits (4000)
- Soil organic matter (1500)
- Atmosphere (750)
- Terrestrial plants (560)
Terrestrial carbon cycle
CO2 emitted by respiration and death and composition
CO2 absorbed by photosynthesis
Main transfers in carbon cycle
Psynth - CO2 + water = glucose + oxygen
Respiration - glucose converted into energy and CO2 returned to atmosphere
Decomposition - Organisms consumed by decomposers like fungi and worms - during this carbon is released
Combustion - burning of organic material
Weathering - breakdown or decay of rocks
C sequestration - transfer from atmosphere to plants, soils, rocks and oceans
Temperature and the carbon cycle
In theory carbon dioxide levels dictate temperature and temperature change however temp change also has an impact on CO2 levels
Impact of 1) cold and 2) warm conditions on carbon stores
1) Chemical weathering more active as cold water holds more CO2
1) Forest coverage would have been significantly different
1) Soil and permafrost would have stopped transfers
2) Carbon stored within the permafrost is now being released - incr warming - incr meting (+ feedback)
Combustion of fossil fuels
- Fossil fuels are natural sources of energy locked away in living organisms
- The burning of this releases energy as well as CO2
Deforestation in contribution to changes in carbon cycle
natural vs human
- Deforestation accounts for about 20% of all global CO2 emissions
- In a natural system a tree releases slowly and slowly releases carbon - as this happens new vegetation starts to grow and compensates for this - carbon neutral
- When trees are burned CO2 is immediately released - on top of this if the land is used for different purposes then the carbon release cannot be compensated for
Modifying industrial combustion
- Carbon capture and storage (CCS) uses technology to capture CO2 from coal fire, transported to a site where it is prevented from entering atmosphere
- Boundary Dam in Canada (2014) became the world first CCS site and aims to cut CO2 emissions by 90%
- CCS is viewed by suspicion by environmental campaigners to due it economic viability - long delays and costs overrun
Modifying photosynthesis
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