Earths life support systems.

Question 1

List some of the importances of water

Answer 1

• 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)

Question 2

List some of the importances of carbon.

Answer 2

• 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

Question 3

What type of systems are the global carbon and water cycle and why?

Answer 3

• Closed systems

Driven by the suns energy, only energy crosses the boundary, not material.

Question 4

Can a carbon and water cycle be an open system?

Answer 4

YES
In small scale, such as in drainage basins and forest ecosystems material can move across defined boundaries.

Question 5

What % of all water on earth does the ocean comprise?

Answer 5

97%

Question 6

What is one of the smallest stores of water and why?

Answer 6

• Atmospheric store.

There is a rapid flux of water into and out of the atmosphere (residence time 9 days)

Question 7

List inputs of water into the atmosphere

Answer 7

• Evapotranspiration
• Ablation (melting and sublimation)

Question 8

List outputs of water from the atmosphere

Answer 8

• Precipitation
• Condensation

Question 9

Name flows in the water cycle

Answer 9

• Precipitation
• Evaporation
• Runoff
• Groundwater flow

Question 10

What is the difference between groundwater flow and runoff?

Answer 10

• Groundwater flow is the HORIZONTAL movement of water within aquifers
• Runoff is the movement of water across land surface.

Question 11

Define infiltration

Answer 11

The vertical movement of rainwater through the soil

Question 12

Define ‘system’

Answer 12

A system is a set of interrelated objects comprising components and processes that are linked to create a dynamic whole.

Question 13

What does the global carbon cycle consist of?

Answer 13

• Stores
• Sinks
• Flows (connects)

Question 14

Name the principal stores in the carbon cycle

Answer 14

• Atmosphere
• Oceans
• Carbonate rocks
• Fossil fuels
• Plants
• Soils

Question 15

What is the biggest carbon store?

Answer 15

Carbonate rocks (such as limestone and chalk alongside deep ocean sediments)

Question 16

What are the two categories of carbon cycle?

Answer 16

• Slow carbon cycle
• Fast carbon cycle

Question 17

What is the slow carbon cycle

Answer 17

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)

Question 18

What is the fast carbon cycle?

Answer 18

The rapid circulation of carbon between atmosphere, oceans and biosphere.
These transfers are between 10-1000x faster than the slow carbon cycle transfer.

Question 19

What are the key components of the fast carbon cycle

Answer 19

• Terrestrial plants and phytoplankton (absorb CO2)
• Respiration and decomposition (returns CO2)
• Dissolving in the ocean.

Question 20

What are the main flows involved in the slow carbon cycle?

Answer 20

• 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

Question 21

State the water balance equation

Answer 21

Precipitation (P) = Evapotranspiration (E) + Streamflow (Q) ± Storage

Question 22

What are the 7 principal flows in the water cycle?

Answer 22

• Precipitation
• Evaporation
• Transpiration
• Run-off
• Infiltration
• Percolation
• Throughflow

Question 23

How is precipitation formed?

Answer 23

• 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

Question 24

In what 3 ways can precipitation impact drainage basins?

Answer 24

• 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

Question 25

How is transpiration influenced by temperature and wind speed?

Answer 25

• 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.

Question 26

What is a feature of cumuliform clouds and how are they formed?

Answer 26

• 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.

Question 27

What is a feature of stratiform clouds and how are they formed?

Answer 27

• Layered clouds
• Air moves horizontally across a cooler surface and mixes with turbulence (ADVECTION)

Question 28

What is a feature of cirrus clouds?

Answer 28

• Wispy clouds formed at high altitude.
• DO NOT produce precipitation so have little influence on the water cycle.

Question 29

What are the 4 ways in which clouds are formed?

Answer 29

• 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.

Question 30

Name the 3 lapse rates.

Answer 30

• Environmental lapse rate (ELR)
• Dry adiabatic lapse rate (DALR)
• Saturated adiabatic lapse rate (SALR)

Question 31

What is a lapse rate referring to?

Answer 31

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.

Question 32

What is the environmental lapse rate (ELR)

Answer 32

• 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.

Question 33

What is the dry adiabatic lapse rate?

Answer 33

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.

Question 34

What is the saturated adiabatic lapse rate?

Answer 34

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.

Question 35

Describe convection in more detail

Answer 35

• 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.