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OCR A LEVEL GEOGRAPHY > Earth Life Support Systems > Flashcards

Earth Life Support Systems Flashcards

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1
Q

What is the importance of water?

A

Flora- photosynthesis, transport of nutrients
Climate - Large specific heat capacity, most potent greenhouse gas, clouds
People - Manufacturing, irrigation, sewage, drinking
Fauna - sweating to cool, circulation of 02, chemical reactions,

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2
Q

How does the water cycle aid development?

A

Water allows for the generation of electricity, irrigation of crops and manufacturing developing the economy.

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3
Q

What are the three main stores of the global water cycle?

A

Atmosphere, land, oceans

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4
Q

What is the goldilocks zone and how does it allow life on Earth?

A

165 Million km from the sun, just the perfect temperature for liquid water. Too close water will be gas, too far will be solid.

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5
Q

What are the four main flows of the global water cycle?

A

precipitation, evapotranspiration, run-off, groundwater flow.

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6
Q

What is the input of energy into the global water cycle?

A

Incoming solar radiation and also is outputted

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7
Q

What type of system is the global water cycle?

A

Closed - only energy leaves

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8
Q

At a local scale (such as a drainage basin) what type of system is the water cycle ?

A

Open as water can leave the system as well as sediment

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9
Q

What is a negative feedback loop at a global scale for the water cycle?

A
  1. Rising temperature
  2. More evaporation
  3. Atmosphere stores more water vapour
  4. More cloud cover
  5. Reflects more solar radiation
  6. Decrease in temperature
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10
Q

What is a positive feedback loop at a global scale for the water cycle?

A
  1. Rising temperature
  2. More evaporation
  3. atmosphere holds more water vapour (greenhouse gas)
  4. More condensation
  5. Latent heat increases due to condensation
  6. Higher temperatures
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11
Q

What is a negative feedback loop at a local scale for the water cycle?

A
  1. Increase in precipitation
  2. Increase in river flow
  3. Excess water recharges aquifers
  4. Less river flow
  5. Less evaporation as water stored in aquifer
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12
Q

What is a positive feedback loop at a local scale for the water cycle?

A
  1. Increase in precipitation
  2. Increase in river flow
  3. Excess water recharges aquifers
  4. More surface run off
  5. More evaporation
  6. More precipitation
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13
Q

What is a positive feedback loop at a micro scale (individual tree) in the water cycle?

A
  1. Drought
  2. Stressed tree
  3. Water lost in transpiration
  4. Not replaced in uptake from soil
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14
Q

What is a negative feedback loop at a micro scale (individual tree) in the water cycle?

A
  1. Drought
  2. Stressed tree
  3. Shed leaves to reduce transpiration
  4. Water stored in tree
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15
Q

How large are the stores (Atmosphere, oceans and land) in the global water cycle?

A

Oceans - 1,370,000 km^3 x 10^3
Land - 39,000 km^3 x 10^3
Atmosphere - 13 km^3 x 10 ^3

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16
Q

How much of the worlds water is saline?

A

97%

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17
Q

What are 5 stores of water on Earth?

A

Lithosphere - Rigid outer part of the Earth consisting of the upper mantle and crust (GROUNDWATER = 9,500KM^3 X 10^3)
Biosphere - The space at the Earths surface occupied by living organisms (0.6KM^3 X 10^3)
Hydrosphere - All the water on the Earth’s surface such as lakes and seas. (1,370,000 KM^3 X 10^3)
Cryosphere - The frozen part of the Earth’s surface (ice caps, sheets and glaciers (29,000KM^3 X 10^3)
Atmosphere - Gases around the planet (13KM^3 X 10^3)

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18
Q

What percentage of fresh water is stored in aquifers?

A

25%

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19
Q

Name all the flows part of the global water cycle?

A

Evaporation
Sublimation
Transpiration
Evapotranspiration
Condensation
Ablation
Precipitation
Interception
Run-off
Infiltration
Groundwater flow
Percolation

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20
Q

At the scale of a drainage basin what are the likely inputs, outputs, flows and stores?

A

Inputs - Precipitation
Outputs - Evapotranspiration, evaporation, transpiration
Flows - Ablation, interception, stem-flow, throughflow, overland flow, infiltration, percolation, groundwater flow
Stores - Puddle, vegetation, river, lake, soil moisture, ground water, channel storage, glacier.

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21
Q

What is the water balance?

A

The balance between inputs and outputs in a drainage basin. The equation is
Precipitation = Evapotranspiration + Discharge +/- storage

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22
Q

What is water surplus and water deficit?

A

Water surplus - precipitation is greater than evapotranspiration leading to saturated soil
Water deficit - Precipitation is less than evapotranspiration leading to dry soil

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23
Q

What is precipitation?

A

Water and ice that falls towards the ground. Forms when vapour in the atmosphere cools to its dew point and condenses. Because the hot water vapour rises, higher up is cooler, so cools gas to a liquid.

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24
Q

What are the three characteristics of precipitation?

A

Intensity - If high, more rapid overland flow into streams and rivers so more chance of flooding.
Duration - Depressions and frontal systems, may deposit exceptional amounts of precipitation increasing change of flooding.
Frequency - Some places can have increased chances of precipitation in rainy seasons. In dry season will be less. During rainy seasons river discharge is high so flooding is common.

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25
Q

What is transpiration?

A

The diffusion of water vapour to the atmosphere from the stomata of plants. Responsible for 10% of the moisture in the atmosphere. Influenced by temperature, wind, humidity and light intensity.

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26
Q

What factors effect transpiration?

A
  1. Temperature - if increased water molecules diffuse faster creating faster transpiration
  2. Wind - Removes water molecules as the pass out through the stomata allowing for more transpiration
    (concertation gradient)
  3. Humidity - If decreased transpiration will increase as less water vapour is outside the leaf.
  4. Light intensity - If increased allows for increased photosynthesis, and so water vapour will diffuse out of the
    leaf faster, increasing transpiration.
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27
Q

What does the water budget graph display?

A

The water balance through the year, with precipitation, soil moisture, soil moisture recharge and field capacity.W

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28
Q

What is field capacity?

A

The maximum amount of water soil can hold until it becomes completely saturated.

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29
Q

In what month will soil moisture recharge happen?

A

Autumn months

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30
Q

During what months will there be a water surplus?

A

December to April (more precipitation in the winter and will exceed water evapotranspiration as leaves fall)

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31
Q

What is soil moisture utilisation?

A

Where plants uptake water from the soils for photosynthesis.

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32
Q

What is discharge?

A

Volume of water (cross sectional area x rivers mean velocity).

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33
Q

What is a storm hydrograph?

A

A graph that shows how a rivers discharge responds to a storm event

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34
Q

What is the lag time on a hydrograph?

A

Period of time between maximum precipitation and peak discharge

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35
Q

What is the peak discharge?

A

Maximum discharge in the river.

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36
Q

What is the rising and falling limb?

A

The river discharge increasing and decreasing

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37
Q

What is the base flow?

A

The normal discharge of the river

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38
Q

What are the two types of hydrograph?

A

Flash and non-flashy

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39
Q

What is a flashy hydrograph?

A

Small lag time, steep rising limb, high peak discharge

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40
Q

What is a non-flashy hydrograph?

A

High lag time, small peak discharge, gentle rising limb.

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41
Q

What is throughfall?

A

Rainfall, initially intercepted by vegetation which drips to the ground

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42
Q

What is stemflow?

A

Flow of water along the branches and stems of trees and other plants to the ground

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43
Q

What is infiltration capacity?

A

The maximum rate at which water under the pull of gravity soaks into the soil.

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44
Q

What is a catchment?

A

The area drained by a river and its tributaries.

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45
Q

What is evaporation?

A

-Phase change of liquid to water vapour
-Main pathway which water enters the atmosphere
-eat is needed to bring evaporation to break the bonds between the water molecules.

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46
Q

How does evaporation distribute heat globally?

A

-Energy input of evaporation does not lead to an increase in temperature
-Instead the energy is absorbed so the atmosphere is cooled as latent heat is taken in.
-This latent heat is then released in condensation
-Affects tropical rainforests daily
-Affects polar regions seasonally

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47
Q

What are some factors that influence interception?

A
  1. Interception storage capacity - Dry vegetation has a higher ability to retain water, as vegetations becomes saturated, output of water through stem flow and through fall increases
  2. Wind speed - Evaporation increases as humidity decreases, and turbulence increases through fall
  3. Vegetation type - Greater losses from grasses than agricultural crops, trees have a higher surface area and aerodynamic roughness increases interception.
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48
Q

What factors affect groundwater flow?

A
  1. Saturation of soil - More saturated, water will flow slowly and wont intercept
  2. Amount of surface vegetation - Will cause more interception decreasing the amount of water entering the ground
  3. Porosity of soil - Will determine the percolation rate
  4. Gradient of slop - Will determine how fast the groundwater flows.
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49
Q

How and why does overland flow (surface run off) occur?

A

Occurs when water flows over an impermeable surface
May flow over due to the ground being to saturated, or if the soils are impermeable or because the rainfall is too intense.

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50
Q

Through what process do clouds form?

A

Condensation

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51
Q

What are three types of clouds?

A

Cumuliform
Stratiform
Cirrus

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52
Q

What are cumuliform clouds?

A

-Flat bases and considerable vertical development
-Form when air is heated locally through contact with the Earths surface
-Causes heated air parcels to rise through the atmosphere expand and cool
-As cooling reaches the dew point the cloud forms.
-Precipitation occurs so impact the water cycle

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53
Q

What are stratiform clouds?

A

-Layer clouds
-Develop when air mass moves horizontally across a cooler surface (ocean)
-Known as advection
-Precipitation occurs so impact the water cycle.

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54
Q

What are cirrus clouds?

A

-Wispy clouds
-Form at high altitudes
-Consist of tiny ice crystals
-They do not produce precipitation
-Little influence on the water cycle

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55
Q

What happens to the temperature of air as you travel up the troposhpere?

A
  1. Troposphere is the lowest portion of the Earth’s atmosphere and is also where most of the worlds weather takes place containing 75% of the atmospheres mass and 99% of the water vapour
  2. As you go up, the temperature decreases at a rate of 6.5 degrees C/KM
  3. This decrease in temperature is called the ELR (Environmental Lapse Rate)
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56
Q

What is the rate of temperature decrease as you go up in the troposphere and what is this called?

A

6.5°C/KM

Called the ELR (Environmental Lapse Rate)

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57
Q

Explain how a “parcel” of air changes as it moves up the troposphere

A
  1. The parcels rise at 18-13 degrees under confined pressure
  2. At 8 degrees the parcels reach the dew point so clouds begin to form
  3. It will continue to rise until the parcel is the same temperature as the ELR
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58
Q

How do parcels of air get heated and what happens to it?

A

At the Earths surface because air is warmer than surrounding air so will begin to rise.

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59
Q

What is adiabatic expansion?

A

Description of what happens to a parcel of air as it rises as air pressure decrease causing an increase in volume and a decrease in temperature.

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60
Q

What is DALR?

A

Dry adiabatic lapse rate: is the rate at which a parcel of dry air (less than 100% humidity so that condensation is NOT taking place) cools. Cooling caused by adiabatic expansion is approximal 10°C/KM

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61
Q

What is SALR?

A

Saturated adiabatic lapse rate: is the rate at which a saturated parcel of air (one in which condensation IS occurring) cools as it rise through the troposphere. The rate of cooling is slower (7°C/KM) because condensation releases latent heat.

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62
Q

Why does saturated air cool more slowly than dry air?

A

Saturated air contains condensed water (water that has turned from a gas to a liquid). When condensation occurs, latent heat is released. The exact opposite of evaporation. This prevents air from cooling as rapidly as heat is released.

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63
Q

Other than warming of air, how else can air parcels rise?

A
  1. Topography of land - Air is forced to rise of over a barrier of mountains of hills. It then cools as it rises.
  2. Convergence - streams of air flowing from different directions are forced to rise where they converge, creating cumulus clouds and showery conditions.
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64
Q

What are the three relationships between ELR, DALR AND SALR?

A

Absolute instability
Absolute stability
Conditional instability

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65
Q

What is absolute atmospheric instability?

A

-Where wet air continues to rise as it is WARMER than its surroundings
-When DALR is to the right of the ELR curve, the parcel of air is warmer than the surroundings.
-As the parcel of air rises it cools until the dew point when it is 100% saturated and condensation occurs
-Creates cumulus clouds with thunder storms. Occurs in the summer in the UK.

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66
Q

What is absolute atmospheric stability?

A

-When the DALR is to the left of the ELR curve, the parcel of air is COOLER than its surroundings.
-The air may be forced to rise due to a mountain range
-But the parcel of air cools more rapidly than the air surrounding it
-By the time the parcel has reached the condensation level it is cooler than the surrounding air, so it doesn’t condense and sinks.
-This creates sunny, dry conditions

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67
Q

What is conditional atmospheric instability?

A

-Initially the ELR is to the right of the DALR curve, meaning that the parcel of air is colder than the surrounding air
-If the parcel of air is forced to rise it will be colder than the surroundings
-This means it would normally sink back down, however if the mountain or cold air mass that originally caused the rise is still there, the air will be cooled to its dew point
-Now condensation occurs, latent heat is released, air cools more slowly at the SALR and the parcel of air may become warmer than its surroundings so will rise freely causing unstable atmosphere
-Causes clouds to form above the condensation level.

68
Q

How does agriculture affect the water cycle?

A
  1. Crop irrigation diverts surface water from rivers and ground water to cultivated land
  2. Interception is reduced
  3. Evaporation and transpiration reduced
  4. Ploughing increases evaporation and soil moisture loss
  5. Compaction of ground from livestock made more run off
69
Q

What are the two types of farming?

A
  1. Crop harvesting
  2. Livestock
70
Q

How does forestry affect the water cycle?

A
  1. Increases evaporation
  2. Higher rates of interception
  3. Compared to farmland and moorland, transpiration rates are increased.
  4. Relatively long lag times and low peak flows
  5. Reduced run off and stream discharge
  6. Fast changes to the water cycle when forest are felled
71
Q

How does water abstraction effect the water cycle dynamic equilibrium?

A

Will affect both the surface and ground water to meet public, industrial and agricultural water demands by impacting the flows and storage.

72
Q

How does water abstraction effect the water cycle in the river Kennet (Southern England)?

A

-Rates of abstraction exceed recharge rate (deficit)
-Lower flows
-Lower groundwater - lower water table
-Springs dry up

73
Q

What is an aquifer?

A

Are permeable and porous rocks such as chalk or new red sandstone

74
Q

How do aquifers impact flows of rivers?

A

Groundwater that passes through aquifers from recharge zones, will flow along the water table and feeds rivers.

75
Q

What were the consequences of overexploitation of the London aquifer?

A

-Caused a drastic fall in the water table
-London fell by 90m
-In the past 50 years, water has declined in demand so has recovered.
-By 1990, it was rising at a rate of 3m/yr.
-Began to threaten buildings so abstraction was used to reduce the rise.

76
Q

What are three time scales that affect the water cycle?

A

Diurnal
Seasonal
Long term

77
Q

What are diurnal changes relating to the water cycle?

A

-Significant changes occur over a 24 hour period (Daily)
-Lower evaporation and transpiration at night
-Low temperature, condensation forms fog mist and dew.

Caused by convectional precipitation falling during the afternoon

ONLY REALLY IMPORTANT IN THE TROPS DUE TO RECYCLING OF WATER

78
Q

What are seasonal changes relating to the water cycle?

A

-Still short term changes
-Controlled by variations in solar intensity throughout the year
-Transpiration will be highest during the summer, lowest during the winter
-As a result river flows in England are normally at the lowest in late summer

CRUCIAL TO THE WATER CYCLE IN ARCTIC

79
Q

What are long term changes relating to the water cycle?

A

-Glacial cycles, 4 major cycles in the quaternary
-Last glacial maximum 18,000 years a go
-Positive feedback causing more ice to form

-Ice sheets destroy forests and grasslands removing water from the biosphere and to the cryosphere.
-Lower rates of transpiration
-Permafrost expands south

80
Q

What are the main satellites to monitor the water cycle?

A
  1. NASA Earth Observing System - Measures arctic sea ice
  2. ICESAT 2 - Measures surface height of ice sheets
  3. NOAA - Measures the radiation emitted from the ocean surface to see temperature
  4. NOAA Polar orbiter - Measures cloud liquid water vapour
81
Q

What happens to the water cycle after human activities?

A
  1. Evapotranspiration reduced from 40% to 20%
  2. Ground water storage reduced from 40% to 20%
  3. Run off increased from <1% to 30%
82
Q

What are 5 human activities that cause changes to the water cycle?

A
  1. Population growth - Rise in demand for water (drinking, agriculture, irrigation etc)
  2. Economic growth - Better technology to abstract water causing water table to lower
  3. Urbanisation - Population increase causes more housing reducing evapotranspiration, precipitation and increases surface run off
  4. Deforestation - Room for rising demand for food, less infiltration and percolation
  5. Energy consumption - Use of water for cooling, water based energy.
83
Q

What are two management strategies to protect the global water cycle?

A

Forest management
Water allocations
As well as agricultural improvments

84
Q

What are three examples of forest management strategies to protect the global water cycle?

A

REDD programme - Reducing emission from deforestation and forest degradation
World Banks FCPF - Forest carbon partnership facility

Together they fund 50 partner countries, offering financial investments to protect and restore forests.

ARPA - Amazon fund to protect 10% of the Amazon

85
Q

Name two examples of water allocation strategies?

A

The Colorado Basin, USA
River Indus, Pakistan, India

86
Q

What happened in the Colorado basin allocation strategy?

A
  1. The water availability was less than estimated
  2. Agriculture use was higher than expected
  3. Didn’t take in the fact of climate change
  4. High amounts of abstraction than expected
  5. So the compact didn’t take into these facts and the basin dried out
  6. However Colorado re-wrote the compact, so there is better management for the water level.

WASNT SUCCESSFUL AS IT WAS UNDERESTIMATED THE ABSTRACTION GROWTH OF POPULATION, DEMAND FOR SUPPLY

87
Q

What happened in the Indus Basin allocation strategy?

A
  1. India has built dams which slow down the water an Eastern tributary causing conflict.
  2. Climate change depleting the store as well
  3. Population growth also depleting the store.
  4. However, a treaty was made for Pakistan to have the North and India to have the south.
  5. But use of water may need to be considered, not just abstraction

WAS SUCCESSFUL AS IT DID REDUCE THE CHANCES OF CONFLICT, BUT WILL NEED TO BE RECONSIDERED FOR OTHER USES OF WATER.

88
Q

What is the importance of the carbon cycle?

A
  1. Carbon is a major building block of life
  2. Green plants and phytoplankton use carbon to photosynthesise
  3. Carbon stores such as ocean sediments and carbonate rocks lock away carbon
  4. Decomposition and oxidation ensure co2 is recycled
  5. Important greenhouse gas that absorbs long-wave radiation from the Earths surface.
89
Q

What are the key stores of the carbon cycle?

A

Biosphere - 560 billion tonnes (0.0012%)
Atmosphere - 750 Billion tonnes (0.0017%)
Pedosphere - 1500 Billion tonnes (0.0031%)
Fossil Fuels - 4000 billion tonnes (0.004%)
Oceans - 38,000 billion tonnes (0.038%)
Lithosphere - 99.9% of all carbon

90
Q

What is the equation for residence time?

A

Amount of carbon in the store / the transfer rate

91
Q

Explain the slow carbon cycle

A
  1. Carbon is stored in the atmosphere
  2. This is then directly absorbed by the oceans forming carbonic acid
  3. This forms calcium carbonate as well
  4. The CaCO3 then sinks to the ocean floor, building layers over millions of years and compact to create sedimentary rocks with a store of carbon
  5. Heat and pressure creates fossil fuels from dead organic matter
  6. Sea floor spreading causes plates to move, and then subduct under the mantle
  7. Extreme heat causes carbon to be released back to the surface and also via volcanic activity.
  8. Recycled back to the atmosphere.
92
Q

Explain the fast carbon cycle

A
  1. Atmosphere holds carbon
  2. Plants take in the carbon dioxide from the atmosphere via photosynthesis
  3. This is then stored in plants and trees.
  4. Animals then eat the plants and respire as well as digest causing release of CO2 and CH4
  5. Combustion via wildfires also releases CO2 to the atmosphere
  6. Dead organic matter is then decomposed, via aerobic and anaerobic respiration via CO2 and CH4.
93
Q

What are 6 carbon exchanges?

A
  1. Precipitation (CO2 + H20 –> H2CO3)
  2. Photosynthesis (C02 +H20 —> C6H1206 + O2)
  3. Weathering
  4. Respiration
  5. Decomposition
  6. Combustion
94
Q

What is carbon sequestration?

A

Is the capture and long term storage of carbon from the atmosphere from the atmosphere. Occurs naturally but humans are trying to find way of adapting this in order to reduce atmospheric co2.

95
Q

What biome stores the most carbon, and what biomes stores the least carbon?

A

Most: Tropical/sub-tropical rainforests
Least: Arctic Tundra

96
Q

What percentage of C02 is sequestered in the oceans?

A

25-30%

97
Q

What are the two pumps of carbon in the oceans?

A
  1. Physical pump (inorganic)
  2. Biological pump (organic)
98
Q

How does the physical pump work?

A
  1. CO2 is absorbed by the surface waters by diffusion
  2. Surface ocean currents transfer this water to the poles were it cools
  3. The water containing the dissolved CO2 becomes denser and sinks as the water is more saline.
  4. This is called downwelling, and only occurs in the North Atlantic and Iceland.
  5. The carbon can remain at depth for centuries
  6. Eventually the bottom of the water is carried upward towards the coast of Peru and Chile
  7. It then diffuses back into the atmoshpere
99
Q

What is downwelling?

A

Sequestration of carbon from the atmosphere to the oceans

100
Q

What is upwelling?

A

Conditions are optimal for upwelling along the coast when winds blow along the shore. Winds blowing across the ocean surface push water away. Water then rises up from beneath the surface to replace the water that was pushed away.

101
Q

How can future sea surface temperature increase affect the physical inorganic pump?

A

Areas of downwelling will reduce as fresh water ice melts, creating less saline water.
Upwelling will increase as the oceans will increase in temperature meaning that C02 will diffuse into the atmosphere more creating a positive feedback loop.

102
Q

Why is water more saline near the poles?

A

Most of fresh water is stored as ice, so it leaves salty water behind

103
Q

How does the biological pump work?

A
  1. Phytoplankton floating near the ocean surface photosynthesise to produce organic material
  2. Carbon locked in the phytoplankton then falls or gets eaten and accumulates in sediments on the ocean floors
  3. This is the stored here for millions of years with sediment laying on top of eachother creating pressure
  4. This creates fossil fuels, limestone and chalk
104
Q

How will future climate change influence the biological organic pump?

A
  1. Phytoplankton prefer colder water, so will slowly move towards the poles as ocean temperatures increase.
  2. However, the rate of photosynthesis will increase
  3. But the overall number of phytoplankton will reduce therefore less food in the food chain and less organic matter.
105
Q

How does urbanisation affect the carbon cycle?

A

Pedosphere and biosphere store reduced
Photosynthesis and decomposition reduced
Human induced combustion
Carbon cycle slows

106
Q

How does agriculture affect the carbon cycle?

A
  1. Biosphere and pedosphere reduced as ploughing reduces carbon in soils, adding oxygen which increases aerobic respiration releasing CO2 into the atmosphere.
  2. Livestock farming uses space, trees removed and digestion is increased
  3. Soil erosion from rain and wind reduces the carbon store
107
Q

How does forestry affect the carbon cycle?

A

-Increase carbon store in biosphere
- Forest trees extract carbon dioxide from the atmosphere and store in the wood
- Only a n active carbon sink for the first 100 years
- Rotation period of 80-100 years (cut down and planted again)

108
Q

Give facts on how combustion has led to changes in the atmospheric carbon store?

A
  1. CO2 levels are highest for 800,000 years
  2. Without extraction of C02 from the atmosphere from the oceans and biosphere, levels would reach over 500ppm
  3. Since 1750, anthropogenic carbon totals 2000 GT
109
Q

How does the combustion of fossil fuels create a negative feedback loop?

A
  1. Increase in FF
  2. More co2 in atmosphere
  3. Enhanced greenhouse effect
  4. Increase in temperature
  5. More photosynthesis
  6. Removal of co2 from atmosphere
  7. CO2 stored in land sink
110
Q

What are 2 positive feedback loops the combustion of fossil fuels create?

A
  1. Sequestration of phytoplankton decreasing due to higher temperatures killing them
  2. Increased carbonation and ocean acidification - oceans wont hold any more c02 so will be stored in atmosphere
111
Q

What are daily changes known as?

A

Diurnal changes

112
Q

How does the carbon cycle change daily (diurnal changes)?

A

Photosynthesis in day (atmosphere -> biosphere transfer)
Respiration at night (biosphere -> atmosphere transfer)
Diurnal changes during the winter are less important due to deciduous trees shedding

113
Q

How does the carbon cycle change seasonally?

A

More atmospheric carbon in the winter than the summer, due to photosynthesis decreasing in Winter as deciduous trees shed leaves, so most of the carbon is stored in the atmosphere.

114
Q

How does the carbon cycle change over long periods of time (inter-glacial and glacial periods)

A

During glacial periods, atmospheric CO2 is less (180ppm)
During inter-glacial periods, atmospheric CO2 is higher (280ppm)

115
Q

Why is atmospheric carbon lower in glacial periods?

A

Ice covers land, so less carbon is stored in the biosphere
Tundra replaces forests, grasslands and rainforests so photosynthesis is reduced
Decomposition is reduces, so carbon stored is stored in soils than atmosphere
The carbon cycle slows down creating a positive feedback loop of getting colder

116
Q

Why is atmospheric carbon higher in inter-glacial periods?

A

Temperatures are higher, so there is more terrestrial land covered by plants
This causes more photosynthesis, respiration and decomposition
This increases the atmospheric store

117
Q

What are some management strategies to protect the global carbon cycle?

A

International directives - UNFCCC, Kyoto protocol
Wetlands restoration - RAMSAR, EU Habitats directive
Afforestation - REDD Scheme
Agricultural practices

REVISE CC FLASHCARDS

118
Q

What is the average temperature in tropical rainforests?

A

25°c

119
Q

What is the average amount of rainfall in the tropical rainforests?

A

2000mm/yr

120
Q

What are the reasons for rainforests being warm and wet all year round?

A
  1. Curvature of the Earth - Heat is concentrated at the equator
  2. Earth’s axis - The Earth’s axis is tilted, which causes seasons, however at the equator the sun strikes at the same angle with no seasonal change.
  3. Atmospheric circulation - Warm conditions result in low pressure, the warm air rises at the equator with clouds causing instability. This causes thunderstorms to form, as well as latent heat to be produced.
  4. Convectional rainfall - This is rainfall caused by warm air at the Earth’s surface, where it rises, cool and condenses forming clouds due to high evaporation.
  5. Clouds - Cumulonimbus clouds form at low altitudes, which reflect solar radiation so are not as dry and hot as deserts
  6. Solar insolation - Incoming solar radiation that reaches the surface.
121
Q

What are the main water inputs into the amazon system?

A

Due to high rates of evaporation from solar radiation there is lots of precipitation (around 8-20GT a year).

122
Q

What are the main outputs of from the amazon system?

A
  1. Discharge - Average discharge of water into the Atlantic ocean by the amazon is 175,000 m^3 / second, 1/3 pf water is outputted to the ocean and 2/3 is outputted by evapotranspiration.
  2. Export of water vapour to other regions - As clouds form they move West towards the Andes and follow the contours and travel to South West Brazil, where rain is produced.
123
Q

Describe the recycling of water in the amazon system?

A

About 50% of all the rain that falls is recycled into the atmosphere via evapotranspiration. Of the rainfall that is evapo-transpired back into the atmosphere, about 48% falls as rain again.
Natural rainforest system is in equilibrium.

124
Q

Where is the water in the amazon stored?

A

-Atmosphere
-Water in plant tissue
-Soil storage and moisture
-Interception storage

125
Q

What is absolute humidity?

A

The mass of water vapour in a given volume of air

126
Q

What is relative humidity?

A

The mass of water vapour in a given volume of air as a ratio of the mass needed to saturate it.

127
Q

What are three physical factors affecting the stores and flows in the Amazonian water cycle?

A
  1. Geology
  2. Relief
  3. Temperature
128
Q

How does geology affect the Amazonian water cycle?

A

Crystalline igneous shields - rocks which is impermeable so run-off is common.
Sedimentary basin rocks - chalk, sandstone and limestone which are permeable and porous, therefore stored in aquifers instead.

In summary influences the groundwater flow and overland flow.

129
Q

How does relief affect the Amazonian water cycle?

A

Andes mountains have steep relief. Relief changes and the gradient was very low. Is only 15m above sea level with 1cm per km drop in gradient. In areas of gentle relief, water moves via throughflow, ground water and during storm events creating run off. In very flat areas huge wetlands form which is a key water storage.

130
Q

How does temperature affect the Amazonian water cycle?

A

25 degrees creates convectional rainfall. This leads to 48% of the water being recycled. Creates high rates of evapotranspiration and absolute humidity (air holds lots of water) which causes high water vapour in the atmosphere, creating lots of condensation and rainfall.

131
Q

What drives deforestation in the Amazon?

A

Agriculture

132
Q

How does deforestation affect the water cycle flows in the Amazon?

A
  1. Increased surface run-off
  2. Reduced photosynthesis and transpiration
  3. Reduced humidity and precipitation
  4. More droughts
133
Q

What is the hydrograph like in the Amazon before and after deforestation?

A

Before - will be a non-flashy hydrograph due to little run-off creating a peak discharge
After - Flashy hydrograph due to more run-off.

134
Q

How does deforestation affect the water cycle stores in the Amazon?

A

Decreased atmospheric storage - less cloud albedo due to less trees
Decreased interception storage - less due to less trees
Decreased aquifer storage - less groundwater flow and saturation means it cant percolate
Increased soil moisture storage - less trees and low interception exposes soil, but due to dryness, large amount of precipitation will mean that it wont penetrate
Decrease in tree storage - due to less trees

135
Q

What happened in the Madeira basin in April of 2014?

A
  1. Flooding - Caused by deforestation creating run off due to dry soils (reached 19.68m, 60 people died and 68,000 evacuated)
  2. Reduced storage in soils and permeable rocks so faster run off
  3. Interception and evapotranspiration reduced due to deforestation, led to droughts as it caused less precipitation
  4. Changes to the albedo - less forest and cloud albedo to reflect radiation.
  5. Regional rainfall - decreased due to evapotranspiration decreasing (less trees).
136
Q

What is the Net Primary Productivity (NPP) in the Amazon?

A

2500 grams / m^3 / yr

Is high because high levels of photosynthesis due to evergreen trees

137
Q

What is Net Primary Productivity?

A

The amount of carbon taken up from the atmosphere/biosphere after subtracting plant respiration.

138
Q

Why is there rapid cycling of carbon between the atmosphere and biosphere in the Amazon?

A
  1. High temperatures leading to increased photosynthetic rates
  2. Same high temperatures and humidity speed up decomposition and the cycles of CO2 to the atmosphere via respiration
139
Q

How do soils affect the carbon cycle in the Amazon?

A

Most soils are not fertile and limited in terms of nutrients.
Carbon is washed out by high infiltration rates due to intense rainfall
All biomass is supported by a thin layer of dark soils called Humus (organic, deep soils).

140
Q

How are nutrients recycled in the Amazon between soils and trees?

A
  1. Trees shed leaves all year round
  2. High temperatures decompose leaves quickly
  3. Organic carbon and nutrients enters the thin humus layer
  4. Shallow roots take up nutrients and organic carbon rapidly
  5. Trees grow rapidly
141
Q

How much carbon is stored in the Amazon?

A
  1. 100 billion tonnes of carbon is locked in the Amazon
  2. 2.5 billion tonnes of C02 sequestered per year
  3. 1.7 billion tonnes of C02 released to the atmosphere per year
142
Q

How do physical factors affect the carbon cycle in the Amazon?

A
  1. Temperature and moisture - High temperatures and rainfall causes more photosynthesis, so more co2 absorbed from the atmosphere rapidly. Also high decomposition rates means CO2 rapidly releases to the atmosphere. RAPID RECYCLING OF CARBON
  2. Geology - Most of the amazon is igneous so contain little carbonate rocks and are hard to weather so
    GEOLOGY IS NOT A KEY STORE OF CARBON IN THE AMAZON.
143
Q

How does deforestation affect the carbon cycle in the Amazon?

A
  1. Less carbon in the biomass
  2. Individual trees are reduced from 180 tonnes to 43 tonnes, therefore rate of photosynthesis is reduced from 30.4 tonnes to 12.3 tonnes.
  3. Less dead organic matter added to the soils
  4. The carbon is then stored in the atmosphere instead of the biosphere
  5. Decreased inputs, increased outputs.
144
Q

What happens to the biomass if the land use changes in the Amazon?

A

-Areas of the rainforest that have been converted to soya plantations the biomass store is only 2.7 tonnes per ha.
-Areas of the rainforest have been converted to grassland, the biomass store is only 16.2 tonnes per ha.

145
Q

Explain why deforestation destroys the main nutrient store in the Amazon

A

-The biomass in trees is destroyed, causing low uptake via roots
-Nutrients are leached from the soil and water store and without protection from trees, soils are rapidly eroded due to run-off.

146
Q

What is the relationship between deforestation and the carbon and water cycle in the Amazon?

A

Deforestation directly affects the water cycle and the carbon cycle
With both in return causing positive feedback loops to eachother
If the water cycle stops the carbon cycle will stop, but if the carbon cycle stops the water cycle isn’t effected.

147
Q

What management strategies have been done to reduce deforestation in the Amazon?

A

Slowed in 2000-2012 by 75% due to:

2008 - Amazon fund
Soy and Beef Moratorium - Stops whole supply chains from buying from exporters who farm in the Amazon
REDD - Norway pledged 1 billion for the amazons fund

Improved agricultural techniques such as rotational cropping and combining livestock, as well as dark soils combining charcoal with manure.

148
Q

What physical factors affect the Arctic Tundra water cycle?

A

Temperature
Humidity
Permafrost
Geology
Precipitation
Relief

149
Q

How does temperature affect the Arctic Tundra water cycle?

A

-Negative heat balance for 8-9 months of the year, creating the albedo effect
-Few plants have adapted to the conditions: Lichen, moss and shrubs
-Only 3 months where temperature rises above 0
-Means that there is little transpiration and evaporation
-Means that water precipitates as snow

150
Q

What is the humidity like in the Arctic Tundra?

A

-Limited precipitation that falls as snow
-Low temperatures means that there is little moisture so low absolute humidity
-Limited transpiration so is less humid

151
Q

How does permafrost affect the Arctic Tundra water cycle?

A

-Is the layer of soil that remains frozen throughout the year
-Affects the water storage and processes
-Most of the water is stored in the pedosphere frozen in the soil.
-In summer temperatures are over 0 degrees so a short period of growth for plants which is very rapid so rapid photosynthesis
-Is a barrier to infiltration and percolation of water
-Storage of water in groundwater
-In summer the active layer melts

152
Q

How does geology affect the Arctic Tundra water cycle?

A

-Precambrian igneous rocks
-Permeability is low- so causes pools of water to form when the permafrost melts

153
Q

How does relief affect the Arctic Tundra water cycle?

A

-Much of the Tundra is flat
-Little run-off
-Winter - snow stays on the surface
-Summer - flat relief means pools of water appear on the surface (called standing , rather than percolating or running off.

WATER IS CYCLE IS SLOW

154
Q

How does the water cycle change seasonally in the Arctic Tundra?

A

Winter
1. Sub zero in winter
2. Water stored as ground ice in permafrost
3. Limited evapotranspiration

Summer
1. Above 0 degrees in summer
2. Liquid water on surface
3. Some evapotranspiration from water in pools and exposed plants
4. Temperatures rise in summer
5. Snow on surface and active layer melts
6. Temporary ponds appear
7. Doesn’t infiltrate due to permafrost layer below.

155
Q

What is the NPP in the Arctic Tundra?

A

200g/m^2/yr

156
Q

What is the carbon cycle like in the Arctic Tundra?

A

Very slow due to little storage in the biosphere via photosynthesis, is mostly stored in the permafrost

157
Q

What are the seasonal changes to the carbon cycle in the Arctic Tundra?

A

-In the short growing season in summers, carbon is transferred from plants into the soil (leaf litter created and decomposition occurs)
-Microorganisms are more active in summer, and break down the leaf decay to release CO2
-Standing pools of water means anaerobic respiration occurs releasing methane
-Carbon is then transferred to the atmosphere.

158
Q

How is the permafrost a large carbon sink in the Arctic Tundra?

A

-Full of dead organic matter untouched for 1000 years as it is frozen
-Low temperatures freeze the matter so slow decomposition
-Permafrost stores 1600 GT of carbon, more than the amazon

159
Q

How will the carbon store change in the future in the Arctic Tundra?

A
  1. Increase in temperature
  2. Increase temperature causes permafrost to thaw
  3. Frozen organic matter thaws and starts to decay
  4. Decomposition of dead organic matter release co2 and methane
  5. More co2 and methane released into atmosphere store

Furthermore, as climate change increases, active layer will deepen as more permafrost melts, this releases methane, but allows for liquid water and space for plant growth so more sequestration of carbon.

160
Q

What resource was found in Alaska?

A

Oil and gas

161
Q

What were the reasons for production of oil and gas in Alaska?

A

-High global energy prices
-US government policy to reduce dependence on foreign countries for oil and gas
-War was breaking in the Middle East
-Potential oil embargo

162
Q

What were the problems for extracting oil and gas in Alaska?

A

-Earthquake prone
-Harsh climate
-Huge variations in temperature would cause pipes to expand and contract causing splitting
-Remote and poor access, water was frozen so pipeline needed a solution
-Permafrost couldn’t bury pipeline and needed to raise it off the ground or the oil would freeze and damage the pipeline

163
Q

What was the solution to solve the problems with the Trans-Alaskan pipeline?

A

-A pipeline was designed in a zig-zag configuration to help relieve the effect of contraction and expansion
-Due to ring of fire, earthquakes form and especially transform faults, so plates moved on different sides, so sliders were made to reduce the pipelines cracking during earthquakes
-Built the pipeline above ground so the permafrost wouldn’t freeze the oil as well as insulation of the pipeline

164
Q

What effects did the Trans-Alaskan pipeline have on the water and carbon cycle?

A

-Changes the volume in the stores and the rate of transfer between them, which upset the equilibrium.
-Melted the permafrost as well
-Oil spills were common

165
Q

How large of a carbon sink are wetlands

A

cover only 3% of the surface area of all land on earth, they contain 550Gt of carbon

OCR A LEVEL GEOGRAPHY (7 decks)

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