Geography OCR A Level: Topic 1.2 - Earth's Life Support Systems Flashcards
3 importances of water
- key to understanding the evolution of life on earth as it provides a medium that allows organic molecules to mix and form more complex structures
- global patterns of weather and precipitation are dictated by the movement, quantity, and temperature of the water, both in the ocean and in the atmosphere
- water vapour a greenhouse gas absorbs radiation and due to this, the planet is 15 degrees warmer than it should be
uses of water for humans
- 2/3s of agriculture use
- 1/5 of industry use
- 1/10 of domestic use
- strong hydrogen bonding in water it cannot be compressed therefore it is good at supporting organisms
uses of water for flora and fauna
plant growth
flooding rivers carries nutrients to floodplains
goes through the soil filtering out any pollutants
4 importances of carbon
building blocks of life
basis of world economy - fossil fuels, plastic and building materials
makes up CO2 which regulates global climate
versatile as it is highly reactive so can combine with many elements to produce a variety of compounds
uses of carbon in natural world
present in chlorophyll which traps solar energy and this helps to form carbohydrates
uses of carbon in humans
large scale exploration of fossil fuels has provided energy for industrial development
What is a open system?
energy and matter are exchanged with the surroundings e.g. human processes
What is a closed system
A system where neither matter nor energy can enter or leave e.g. putting a lid on the frying pan
are carbon and water cycles open or closed
closed
List the four features of a water and carbon cycle
atmosphere, oceans, land and biosphere (where all parts of earth exist e.g. rock,water, air and the rest of the ecosystem)
On smaller scales though like a drainage basin in the water cycle and ocean in the carbon cycle they are
open
What are inputs?
elements that added to/removed from a system, either energy or material
what are stores
places that material is held for a period of time
what are fluxes
measurements of the rate of flow of material between stores
what are processes
physical mechanisms which drive the flux of material between stores
what are transfers
routes that material and energy take as they move between stores
what happens to animals organic matter
converted into carbon rich sedimentary rock due to heat and pressure
what is a carbon sink
A place where carbon is stored
examples of carbon sinks (x5)
limestone and deep ocean sediment are the biggest carbon stores
storage in plants, atmosphere and soil is small
4 stages of the carbon cycle
- Photosynthesis is what plants do to create glucose the equation is:
6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O. This means carbon is used. Plants use the chemical energy for processes such as growth where they release CO2 back into the atmosphere - Respiration is carried out by animals and plants to release energy from glucose, the equation is:
C6H12O6 + 6O2 → 6CO2 + 6H2O . This means carbon is produced. - Decomposition: Decomposer organisms like fungi and bacteria breakdown dead organic matter extracting energy and releasing CO2 and minerals to the soil.
- Combustion is burning, if something with carbon is burnt it will release it into the atmosphere, e.g. a tree, fossil fuel.
What is carbon sequestration
a natural or artificial process by which carbon dioxide is removed from the atmosphere and held in solid or liquid form.
Physical inorganic pump: Carbon Sequestration
involves the mixing of surface and deep ocean waters by vertical currents which creates an even distribution of carbon.
initially CO2 diffuses from the atmosphere to the ocean.
surface ocean currents transport this water polewards where it cools becoming denser thus sinks (downwelling)
Trees in rainforests store
lots of carbon
If there are lower temperatures air holds
less water
evaporation is dependent on two things
the temperature
water bearing capacity of air
What is transpiration?
The loss of water from a plant
4 What affects transpiration?
temperature - high so more latent heat of vaporisation thus encourages evaporation
humidity
light
wind
What is latent heat?
the heat required to convert a solid into a liquid or vapour, or a liquid into a vapour, without change of temperature.
When does condensation occur?
when the air in the atmosphere reaches its dew point
at this point the air is saturated with water
why does air reach a saturation point (x2)
the air cools down (can’t hold as much water)
more water is added to the atmosphere
Clould formation (5 steps)
1) A parcel of air at the earth’s surface is warmed so it expands decreasing its density. Therefore it is more buoyant than surrounding air so rises. Now unstable.
2) Increasing in height the parcel experiences decreasing pressures so expands even more and results in it cooling. Adiabatic cooling
3) Before the parcel reaches its dew point it will cool at 10 degrees/100m. Dry adiabatic lapse rate
4) As soon as it reaches its dew point, condensation begins and air now cools at 6.5 degrees/100m. This is saturated adiabatic lapse rate
5) The real vertical temperature profile of an air mass is known as the environmental lapse rate
Bergeron Process
Hot air rises so the water vapour on the ground will continue to rise. As water vapour rises in the atmosphere it becomes supercooled water vapour droplets. It continues to rise. Within a pocket of air higher up there might be some frozen nuclei, along with the supercooled water droplets. If the supercooled water droplets don’t touch the frozen nucleii then it will continue to rise and freeze at much lower temperatures. At -40C Ice crystals form. The Ice crystals might become too heavy and drop. If saturation point is reached the ice crystals can hold no more water vapour at its particular temperature and pressure so will continue to drop due to being too dense. When the temperature increases as the crystals drop through the atmosphere down towards the ground the crystals will start to melt and might turn into rain according to the temperature profile.
what is interception
Water which is stopped by vegetation
3 types of rainfall
Relief: prevailing winds encounter a barrier so the air is forced up, cools, condenses and forms rain.
Convectional: a parcel of air is heated which then rises. As it rises it is then cooled adiabatically. It then goes beyond its dew point so condenses.
Frontal: dense cold air remains close to the ground acting as a barrier to the light warm air which means that the warmer air is forced up above the cold air.
What is infiltration?
the process by which water on the ground surface enters the soil
What is porosity?
Volume of pore space in a material
What is permeability?
ability to transmit water
What is percolation?
the downward movement of water through pores and other spaces in soil due to gravity
Oceans contain how much of the Earth’s water?
97%
How much freshwater is stored in ice caps?
3/4
