Earths life support systems. Flashcards
List some of the importance’s of water
- Creates benign thermal conditions
(Ocean slow release of heat, clouds reflecting solar radiation and water vapour absorbing long-wave radiation) - Metabolic medium for photosynthesis, respiration and transpiration streams.
- Economic activity
(Generate electricity, irrigate crops, provide public demand for water and used in industry)
List some of the importances of carbon.
- Biological significance (carbon is used in the composition of biological molecules such as proteins, carbohydrates and nucleic acids)
- Economic resource (fossil fuels utilised in industry)
- Domestic purpose (heating)
- Insulator
What type of systems are the global carbon and water cycle and why?
- Closed systems
Driven by the suns energy, only energy crosses the boundary, not material.
Can a carbon and water cycle be an open system?
YES
In small scale, such as in drainage basins and forest ecosystems material can move across defined boundaries.
What % of all water on earth does the ocean comprise?
97%
What is one of the smallest stores of water and why?
- Atmospheric store.
There is a rapid flux of water into and out of the atmosphere (residence time 9 days)
List inputs of water into the atmosphere
- Evapotranspiration
- Ablation (melting and sublimation)
List outputs of water from the atmosphere
- Precipitation
- Condensation
Name flows in the water cycle
- Precipitation
- Evaporation
- Runoff
- Groundwater flow
What is the difference between groundwater flow and runoff?
- Groundwater flow is the HORIZONTAL movement of water within aquifers
- Runoff is the movement of water across land surface.
Define infiltration
The vertical movement of rainwater through the soil
Define ‘system’
A system is a set of interrelated objects comprising components and processes that are linked to create a dynamic whole.
What does the global carbon cycle consist of?
- Stores
- Sinks
- Flows (connects)
Name the principal stores in the carbon cycle
- Atmosphere
- Oceans
- Carbonate rocks
- Fossil fuels
- Plants
- Soils
What is the biggest carbon store?
Carbonate rocks (such as limestone and chalk alongside deep ocean sediments)
What are the two categories of carbon cycle?
- Slow carbon cycle
- Fast carbon cycle
What is the slow carbon cycle
The circulation of carbon that has been stored in rocks, sea floor sediments and fossil fuels.
These are characterised by long residence times (150M years)
What is the fast carbon cycle?
The rapid circulation of carbon between atmosphere, oceans and biosphere.
These transfers are between 10-1000x faster than the slow carbon cycle transfer.
What are the key components of the fast carbon cycle
- Terrestrial plants and phytoplankton (absorb CO2)
- Respiration and decomposition (returns CO2)
- Dissolving in the ocean.
What are the main flows involved in the slow carbon cycle?
- Accumulation of crustacean remains that have been subjected to pressure, becoming sedimentary rocks. (INPUT)
- Subduction: the sedimentary rock is sub-ducted into the upset mantle and are vented in volcanic eruptions. (OUTPUT)
- Weathering:
If exposed, the rocks are attacked by chemical weathering such as carbonation. Rainwater combines with atmospheric CO2 to form a weak acid which attacks carbonate minerals. OUTPUT
State the water balance equation
Precipitation (P) = Evapotranspiration (E) + Streamflow (Q) ± Storage
What are the 7 principal flows in the water cycle?
- Precipitation
- Evaporation
- Transpiration
- Run-off
- Infiltration
- Percolation
- Throughflow
How is precipitation formed?
- Water vapour in the atmosphere cools to its dew point.
- It condenses into tiny water droplets or ice particles, forming clouds.
- The droplets or ice particles aggregate, reach a critical size and leave as precipitation
In what 3 ways can precipitation impact drainage basins?
- Form of precipitation
Precipitation can fall as snow in high latitude and mountainous catchments and remain on the ground for months - creates considerable time lag between precipitation and runoff - Intensity of precipitation
The amount falling in a given time, if high it undergoes through-flow, as it is falling at a rate exceeding the infiltration capacity in the soil. - Duration of precipitation
Length that the event lasts - prolonged events cause saturation of the soil which creates overland flow and potential river flooding
How is transpiration influenced by temperature and wind speed?
- Deciduous trees shed their leaves in climates with dry or cold seasons to reduce moisture loss.
- In areas with higher wind speed, such as the unsheltered tundra, water potential is effected.
What is a feature of cumuliform clouds and how are they formed?
- Flat bases and considerable vertical development
- Occur when air is heated locally through contact with earths surface, causing heat parcels to rise in convection and expand (due to fall in altitude pressure) which then cool.
What is a feature of stratiform clouds and how are they formed?
- Layered clouds
- Air moves horizontally across a cooler surface and mixes with turbulence (ADVECTION)
What is a feature of cirrus clouds?
- Wispy clouds formed at high altitude.
- DO NOT produce precipitation so have little influence on the water cycle.
What are the 4 ways in which clouds are formed?
-
Convection
Air is warmed by contact with the ground or sea surface and rises. As the air rises and pressure falls it cools by expansion (adiabatic expansion). -
Advection
Air masses move horizontally across a relatively cooler surface. -
Frontal
A relatively warm air mass mixes with a cooler one. -
Orthographic uplift
Air masses are forced upwards as they cross a mountain barrier or turbulence forces ascent.
Name the 3 lapse rates.
- Environmental lapse rate (ELR)
- Dry adiabatic lapse rate (DALR)
- Saturated adiabatic lapse rate (SALR)
What is a lapse rate referring to?
The vertical distribution of temperature in the lower atmosphere, and the temperature changes that occur within an air parcel as it rises vertically away from the ground.
What is the environmental lapse rate (ELR)
- The vertical temperature profile of the lower atmosphere at any given time.
- The temp falls by 6.5°C for every kilometre of height gained.
What is the dry adiabatic lapse rate?
The rate at which a parcel of dry air (less than 100% humidity so condensation isn’t taking place) cools.
- Cooling is caused by adiabatic expansion at approx. 10°C/km.
What is the saturated adiabatic lapse rate?
The rate at which a saturated parcel of air (where condensation IS occurring) cools as it rises through the atmosphere.
- As condensation releases latent heat the SALR is 7°/km, lower than DALR.
Describe convection in more detail
- The ground heated by the sun warms the air in contact with the surface to a temperature warmer than it’s surroundings
- As the air is now warmer than it’s surroundings, it is less dense and therefore buoyant.
- This is atmospheric instability, creating freely rising air in a convection current.
- When it’s internal temperature reaches dew point (the same temperature externally) condensation occurs and clouds form.
