water and carbon cycle

Question 1

systems?

Answer 1

systems- a set of interrelated components working together towards some kind of process

what are systems made up of?
inputs —> matter or energy is added to the system
outputs —> matter or energy leaves the system
stores —> a part of the system where something is held for a period of time
flows —> a link between 1 store and another, along which something moves
boundaries —> the edge of the system (the line between 1 system and another)

Question 2

open system, closed system and equilibrium?

Answer 2

open system —> energy and matter enter and leave the system

closed system —> energy can enter and leave but matter cannot enter or leave (matter can be water) —> it can only cycle between stores

dynamic equilibrium —> inputs and outputs are equal and the system is in equilibrium —> no overall change to the system

Question 3

positive feedback and negative feedback and examples?

Answer 3

positive feedback —> when a chain of events ​amplifies (increases) the impacts of the original event

negative feedback —> when a chain of events ​nullifies (reduces or stops) the impacts of the original event

positive feedback examples:
- temperatures increase —> ice melts —> less ice cover —> less of the suns energy is reflected —> more of the suns energy is absorbed —> temps increase
- temperatures increase —> ocean temp increases —> warm water less able to dissolve gas —> CO2 released into the atmosphere —> more CO2 to act as a greenhouse gas —> temp increase

negative feedback examples:
- co2 in atmosphere increases —> extra co2 causes plants to grow —> plants remove co2 from the atmosphere —> amount of co2 in the atmosphere decreases

Question 4

the whole earth can be broken down into smaller subsystems such as?

Answer 4

the earth can be seen as 1 system made up of lots of subsystems

hydrosphere —> all the water on earth —> it may be in liquid form (rivers and oceans), solid form (ice stored in the cryosphere) and gas form (water vapour stored in the atmosphere)

lithosphere —> the outermost part of the earth, including the crust and upper parts of the mantle

cryosphere —> all the parts of the earth where it is cold enough for water to freeze e.g. glacial landscapes

atmosphere —> layer of gas surrounding our planet

biosphere —> where living things are found, including plants, animals, fungi, insects and bacteria

Question 5

examples of the spheres interacting?

Answer 5

• Volcanoes may release a large amount of hot lava (lithosphere), which causes glaciers (hydrosphere) to melt. Flooding may occur downstream from volcanoes and may flood communities (biosphere)

Complex interaction between spheres?
- Volcanoes (lithosphere) may emit large quantities of sulfur dioxide (atmosphere)
- When sulfur dioxide combines with water (hydrosphere), sulfuric and sulfurous acid form
- Rain (hydrosphere) may bring these acids to the Earth, acidifying soils (lithosphere), lakes and rivers (hydrosphere)
- Acidic water takes away nutrients from the soil (lithosphere) making it harder for plants to grow (biosphere)
- Acidic water enters the water table (hydrosphere), and the water supply (hydrosphere) becomes less potable for humans (biosphere)
- Acid rain falling on lakes reduces the pH of the water (hydrosphere), which may result in a decrease in phytoplankton and zooplankton growth (biosphere)
- If photosynthesis is reduced, concentrations of carbon dioxide can increase and stimulate global warming (atmosphere) which may contribute to increased melting of glaciers (hydrosphere)

Question 6

how are the spheres linked?

Answer 6

biosphere and lithosphere:
- plants put carbon into soil
- nutrients from rocks help the biosphere grow

biosphere and hydrosphere:
- plankton and other marine producers take up carbon in ocean water

lithosphere and hydrosphere:
- weathering release carbon into rivers + streams

lithosphere and atmosphere:
- volcanic eruptions release carbon trapped inside the earth into the atmosphere
- weathering releases carbon into the atmosphere

atmosphere and hydrosphere:
increased ocean temp —> warm water less able to dissolve gas —> CO2 released into the atmosphere

Question 7

how is the atmosphere linked to the hydrosphere

Answer 7

hydrosphere —> atmosphere (increased ocean temp —> warm water less able to dissolve gas —> CO2 released into the atmosphere)

Question 8

drainage basin and water shed?

Answer 8

drainage basin —> the area surrounding the river where the rain falling on the land flows into that river//catchment area for water

water shed —> area of high land that separates the drainage basins (the boundary of a drainage basin is the watershed)

Question 9

inputs, outputs, stores and flows of the water cycle?

Answer 9

inputs:
- precipitation

outputs:
- evapotranspiration

stores: (CIGSS)
- channel storage - water held in a river
- interception - water stored by trees
- groundwater - water stored in the ground in the pore spaces of rocks
- soil storage - water stored in the soil
- surface storage - water in puddles, ponds and lakes

flows:
- stemflow - water running down a plant stem or tree trunk
- surface runoff/overland flow
- infiltration - water moving from the ground into the soil
- throughflow - flow of water through soil (downhill)
- percolation - water moves from soil into rocks
- groundwater flow - flow of water through rocks
- channel flow- movement of water within the river channel

Question 10

water?

Answer 10

the hydrosphere contains 1.4 sextillion litres of water

most of this is saline water in oceans and less than 3% is freshwater (freshwater is needed for humans to survive)

where is fresh water found?
cryosphere (69% fresh water is found here)
groundwater (30% of freshwater is found here)
liquid freshwater e.g. lakes and rivers (0.3% of freshwater is found here)
water vapour in the atmosphere (0.04% of freshwater is found here)

why can only a small amount of water on the planet be used by humans?
- water must be physically and economically accessible for humans to be able to use it e.g. groundwater is hard to access and it’s not cost effective extract it

Question 11

4 water stores (TOAC)

Answer 11

terrestrial water —> water found in the ground, in the soil, in lakes, in rivers and in wetlands —> rivers and lakes are the most accessible water in the terrestrial system

oceanic water —> water found in oceans —> 97% of all water is found in oceans —> oceans are the biggest store of water

atmospheric water —> water found in the atmosphere —> mainly water vapour and some liquid water (rain droplets) —> around 13000km^3 of water is found in the atmosphere

cyrospheric water —> all of the frozen water e.g. glaciers

Question 12

global hydrological cycle

Answer 12

water is continuously cycled between different stores in a closed system

Question 13

states of water?

Answer 13

• water is made up of 2 hydrogen molecules and 1 oxygen molecule
• strong hydrogen bond between these molecules leads to water surface tension —> lots of energy needed to change its state
• water can change between solid, liquid and gas form —> for water to melt/boil, it has to gain energy —> for water to condense/freeze, it has to lose energy
• sublimation —> change of state from a solid to a gas with no liquid stage
• deposition —> change of state from a gas to a solid

Question 14

what is latent heat

Answer 14

as the water molecules become heated by the sun, they become agitated and they try to break the bonds between them however there’s not enough heat in the sun ray to do this so

the water molecules absorb energy from their surroundings to give them the final energy that they need to break the bonds between them

as latent heat is taken from the surroundings, it cools the surroundings down

Question 15

confluence and tributary

Answer 15

confluence —> where 2 streams meet

tributary —> small stream

Question 16

hydrographs and definitions

Answer 16

hydrographs —> shows river discharge over a period of time

flood hydrographs—> shows river discharge around the time of a storm event

discharge —> volume of water that flows into a river per second
(volume of water - m^3)
(discharge is measured in m^3/s —> cumecs )

lag time —> the delay between peak rainfall and peak discharge —> this delay happens because it takes time for rainwater to flow into a river

peak discharge —> when the river discharge is at its greatest

rising limb —> where the river discharge increases as rainwater flows into the river

falling limb —> where the river discharge decreases because less water is flowing into the river

Flashy:
• Short lag time
• Steep rising and falling limb
• Higher flood risk
• Higher peak discharge

Subdued:
• Long lag time
• Gentle rising and falling limb
• Lower flood risk
• Lower peak discharge

Question 17

what affects hydrographs shapes? (peak discharge and lag time)

Answer 17

size of drainage basin —> larger drainage basins collect more precipitation so they have higher peak discharge// have a long lag time —> water has to travel a long distance before it reaches the river channel

ground steepness —> water flows more quickly downhill so steep ground will mean a short lag time// steep land —> less time to infiltrate —> higher runoff —> peak discharge is higher

soil type —> impermeable soils —> water doesn’t infiltrate —> increases run off —> increase peak discharge// clay soils become saturated very quickly —> results in rapid overland flow —> shorter lag time —> water reaches channel more quickly

vegetation —> more vegetation means more interception —> lag time will be greater as trees slow the movement of water into the river channels// peak discharge is lower —> more interception so less water reaches the channel

Question 18

physical factors affecting the water cycle

Answer 18

precipitation and storms —> storms generate more precipitation —> saturate the soil, allowing no more infiltration —> increasing surface runoff —> increased peak discharge

seasonal changes
summer:
-higher temperature cause the ground to be harder and more impermeable —> infiltration decreases —> surface runoff increases
winter:
-frozen ground prevent infiltration —> increase run off
-winter —> water will freeze —> reduce size of flows through drainage basins and increase size of stores

vegetation
summer —> more vegetation —> more water lost through evapotranspiration —> reduces run off and peak discharge
winter —> less leaves on trees —> less interception —> increases run off and peak discharge —> flooding more likely// less evapotranspiration —> less moisture to condense and form clouds —> less rain

Question 19

human factors affecting the water cycle

Answer 19

land use —> construction creates impermeable surfaces —> reduces infiltration —> increases runoff —> water passes through the system much more rapidly —> flooding more likely

deforestation —> reduces interception, evapotranspiration, and infiltration

water abstraction —> more water is abstracted to meet demand in areas where population density is high —> reduces amount of water in stores like rivers etc// during dry seasons, even more water is abstracted from stores —> stores are depleted further

farming practices (PILC)
ploughing breaks up the surface so more water can infiltrate —> reduces surface run off
crops increase infiltration and interception —> reduces run off// evapotranspiration also increases which can increase rainfall
livestock trample and compact the soil, decreasing infiltration —> increases run off
irrigation (artificially watering the land) —> can increase runoff if some of the water can’t infiltrate

Question 20

how does agriculture impact the water cycle (positive feedback)

Answer 20

deforestation to create space for crops —> less evaporation —> less rainfall —> ground becomes drier and less fertile —> new areas of land are cleared for farmland

Question 21

evaporation, condensation and cyrospheric processes?

Answer 21

the magnitude of each store varies overtime

evaporation:
- liquid water changes state into a gas —> it gains energy from solar radiation
- evaporation increases the amount of water stored in the atmosphere
- magnitude of evaporation flow —> if there is lots of solar radiation and a large supply of water —> evaporation levels will be high
- if there is not much solar radiation and a little supply of water —> evaporation levels will be low
- e.g. long term changes in climate can affect the magnitude of evaporation flow —> during the last glacial period, temps were lower so evaporation was lower

condensation:
- water vapour changes state to become a liquid —> it loses energy to the surroundings
- magnitude of condensation flow —> depends on the amount of water vapour in the atmosphere and the temperature
- if there is lots of water vapour in the atmosphere and there’s a large/ rapid drop in temperature —> condensation levels will be high

cyrospheric processes:
- cyrospheric processes change the amount of water stored as ice in the cryosphere
- during colder periods, the magnitude of the cryosphere stores increases —> water is transferred to the cryosphere as snow and less water is transferred away through melting
- during warmer periods, the magnitude of the cryosphere store reduces —> water is transferred away from the cryosphere through melting and there’s less rain so less snow

changes in cryosphere over a large timescale:
- causes by changes in global temperature

changes in cryosphere over a short timescale:
- caused by annual temperature fluctuations —> more snow falls in the winter than in summer

Question 22

how do clouds form?

Answer 22

• clouds form when warm air cools —> makes water vapour condense into water droplets which gather as clouds —> when water droplets get big enough, it falls as precipitation
• however water droplets are too small to form clouds on their own, there must be tiny particles of other substances (e.g. dust or soot) to act as condensation nuclei

Question 23

what causes precipitation?

Answer 23

other air masses —> warm air is less dense than cool air —> when they meet, the warm air rises —> this makes it cool (it cools down as it rises) so it starts to condense —> creates frontal precipitation

topography —> when warm air meets mountains, it is forced to rise —> this makes it cool so it starts to condense —> creates orographic precipitation e.g. the pennines

convection —> the sun heats up the ground and moisture on the ground evaporates and rises up in a column of warm air —> as it gets higher, it cools —> this causes it to condenses —> results in convective precipitation

Question 24

why do some parts of the earth receive more radiation than other parts? —> more solar radiation —> more evaporation and condensation

Answer 24

• Curvature of the earth —> more solar radiation is received and absorbed near the equator than at the poles —> the suns rays strike the earth most directly near the equator —> while at the poles the rays strike at a steep angle
• The radiation travels through a greater depth of atmosphere nearer the poles —> more radiation is lost to scattering and absorption by gases/particles in the atmosphere
• Snow and ice reflect a lot of the suns radiation back into space

Question 25

global atmospheric circulation?

Answer 25

what does the global atmospheric circulation do?
- equator receives more heat from the sun than the poles so the purpose of global circulation is to redistribute this heat

what happens in a low pressure area and a high pressure area?
- low pressure —> air rises —> clouds form
- high pressure —> air sinks —> sun

**how does the global atmospheric circulation work?
- temps at the equator are high as the sun’s energy is more concentrated —> high temp creates low pressure so air rises —> clouds form which leads to rainfall
- when the air reaches the top of the atmosphere, it needs somewhere to go —> the air travels north and south of the equator —> the air sinks around 30° north and south of the equator —> creates high pressure —> sun
- high temps creates low pressure so air rises at around 60° north and south and descends at around 90° north and south

Question 26

hadley, polar and ferrell cells?

Question 27

water balance?

Answer 27

Water balance- the water balance is the balance between inputs (precipitation) and outputs (evapotranspiration)

P = Q + E (+/- change in storage)

P = precipitation
Q = run-off
E = evapotranspiration

Question 28

how does the water balance show us seasonal patterns? (graph)

Answer 28

in wet seasons —> precipitation > evapotranspiration —> water surplus —> ground stores fill with water —> more surface runoff —> higher discharge —> river levels rise

in dry seasons —> precipitation < evapotranspiration —> ground stores are depleted as some water is used e.g. by plants + humans but isn’t replaced by precipitation —> deficit of water in the ground —> ground stores are recharged in the next wet season

Question 29

soil moisture budget?

Answer 29

• The Soil Moisture Budget shows the annual inputs and outputs to the water cycle and the impact that has on soil water
• Field capacity- maximum amount water that can be stored in the soil —> once the field capacity is reached, any rainfall after this will not infiltrate the soil and is likely to cause flooding
• Soil moisture recharge —> when precipitation exceeds evapotranspiration
• Soil moisture utilisation —> when evapotranspiration exceeds precipitation
• Soil moisture surplus —> when precipitation exceeds evapotranspiration
• Soil moisture deficit —> when evapotranspiration exceeds precipitation

Question 30

river eden case study

Answer 30

facts and location
- the river eden is 145km long and is located in north west of england in cumbria
- the eden drainage basin is in north west england, between the mountains of the lake district and the pennies —> topography —> clouds form —> rain etc
- it’s source is in the pennine hills in south cumbria
- it’s mouth is in the solway firth at the scottish border

physical causes of flooding in the river eden
geology- the upland areas are mainly igneous rock —> impermeable surface —> less infiltration —> increased surface run off//low land areas are mainly sandstone and limestone (permeable) which become saturated —> flashier hydrograph
gradient- steep gradient —> elevation drops from 690m to 180m —> water doesn’t have time to infiltrate and will run off —> flashier hydrograph
weather- rainfall is higher than the national average in the eden basin due to topography —> creates orographic precipitation —> around 2800mm annual rainfall in the upland areas —> lead to surfaces exceeding field capacity —> no more water can infiltrate —> runoff increases —> flashier hydrograph
drainage basin shape- carlisle sits at the confluence of the rivers eden, petteril and caldew—> lots of water coming together at 1 point
drainage basin is long and thin —> less places for water to go to —> water concentrated towards carlisle —> flashier hydrograph

human causes of flooding in the river eden
deforestation to make space for housing —> 10,000 new homes built in carlisle —> less trees —> less interception so more water reaches the ground —> surface reaches field capacity —> surface run off increases// also less evapotranspiration —> less water leaving the system —> more water within the drainage basin—> flooding —> flashier flood hydrographs
construction —> surfaces tend to be impermeable —> reduces size of infiltration flows and increases size/speed of surface runoff flows —> flashier hydrograph
farming —> soils become compacted by heavy machinery or trampling by livestock e.g. between 2000 and 2009, there was a 30% increase in the number of cattle in the eden valley —> compaction —> reduces infiltration —> increases surface run off —> increases risk of flooding —> flashier flood hydrographs

Question 31

**flood management techniques (river eden)?

Answer 31

• building 50km of new embankments to increase the capacity of the river eden
• restoring 350 hectares of peatland to hold water upstream for longer
• dredging —> remove gravel and debris from the river eden to increase its capacity
• making available 500,000 additional sand bags + additional temporary defences when necessary