water & carbon cycle - PG unit 1 Y12

What does the inputs of a system mean?

an input into the system from the outside e.g precipitation

What does the outputs of a system mean?

an output from the system to the outside e.g evaporation

What does energy mean in a system?

the power or driving force

What does the stores and components of a system mean?

the individual elements or parts of a system e.g plants

What does the flows/transfer of a system mean?

the links or relationships between components e.g photosynthesis

What is positive feedback?

a cyclical sequence of events that amplifies or increases change

What is negative feedback?

a cyclical sequence of events that damps down/neutralises the effects of a system, promoting stability and a state of dynamic equilibrium

What is dynamic equilibrium?

this represents a state of balance within a constantly changing system

What are the 3 types of system?

open , closed and isolated systems

What are open systems?

allow the exchange of mass and energy with the surroundings e.g a thermal coffee cup + house water system

What are closed systems?

where energy us transferred in and out and all matter is enclosed e.g carbon and water cycle

What are isolated systems?

where no interactions occur with anything outside of the system's boundary e.g sealed vacuum chamber

What is a cascading system?

Open systems that have interlocking relationships between different stores within the system e.g river sediment going into coastal zone

How is a dynamic equilibrium created?

When a system work on a balance of inputs and outputs and if these are even, it then creates a dynamic equilibrium

What happens if the inputs or outputs suddenly change?

the stores are forced to change and the equilibrium is disturbed (known as feedback which can be positive or negative)

What are feedback systems?

a process that uses the conditions of a component to regulate then function of the other to increase to dampen the change in the system

What is a mechanism known as when a process increases change in a system?

positive feedback

What is a mechanism known as when a process counters the change in a system and maintains equilibrium?

negative feedback

What are the 5 subsystems?

• Cryosphere (ice)

• Lithosphere (geology)

• Biosphere (organic life)

• Hydrosphere (water)

• Atmosphere (air)

What is the subsection of the biosphere called?

pedosphere (rock, water and living organisms

What are the inputs and outputs of a drainage basin?

input = precipitation

Output = surface runoff

What are the stores and energy of a drainage basin?

stores = water, soil, trees

energy = latent heat associated in change in state of water , the sun

What are the flows and transfers of a drainage basin?

infiltration , evaporation , groundwater flow

What is the positive and negative feedback of a drainage basin?

positive feedback = rising sea levels, ice shelves become unstable causing them to melt and increasing sea level

negative feedback = increased surface temperature means increased evaporation from oceans , more cloud cover which block out sunlight which reduces temperature

Water on Earth percentage facts:

It is estimated that there is around 1.340 billion km^3 water in total -> 97% as oceanic water and 3% as land ice, glaciers and permafrost (cryospheric water)

What is the water table?

the upper level of saturated rock which rises and falls due to groundwater flow, water abstraction by people or by recharge (additional water flowing into the rock)

What are the 3 states of water?

solid, liquid and gas

What is the process called when a solid turns into a liquid?

melting (fusion)

What is the process called when a solid turns into a gas?

sublimation

What is the process called when a liquid turns into a solid?

freezing (fusion)

What is the process called when a liquid turns into a gas?

evaporation (needs to be 100 degrees C)

(Vaporisation)

What is the process called when a gas turns into a liquid?

condensation (vaporisation)

What is the process called when a gas turns into a solid?

deposition

What happens when water molecules get heated by the sun?

the molecules become agitated and try to break the strong bonds between them but there isn't enough heat in the sun ray to do this so the molecules absorb energy from the surroundings to give them that last bit of energy to break the bonds. This energy is known as latent heat.

What happens in evaporation?

latent heat is removed from the surroundings to cool it down e.g sweat

(evaporation could be seen as a cooling process as it removes heat)

What happens in condensation?

latent heat is released by the water molecules as they slow down and join together

(condensation could be seen as a warming process as it adds heat)

What are the 3 types of rain?

Relief, convection and frontal rain

What happens to make relief rain?

clouds rise over land and rains and then go down the land empty (rain shadow effect)

what happens to make convection rain?

high levels of solar radiation is absorbed by the trees where there is less dense air above them which rises and cools and then condenses which form clouds (usually storm clouds)

What happens to make frontal rain?

Clouds gradually rise higher over warm air and release energy once it can't hold the rain in which produces cold air

What are the cells in the atmospheric circulation?

• polar cells

• Ferrell cells

• Hadley cells

Why does the amount of water in the Earth's stores change over space and time?

it's due to the seasons, temperature, time and where we are in the world

What is atmospheric circulation caused by?

different parts of the earth being heated up by the sun differently to other parts:

the poles are heated up less due to the curvature of the earth, meaning the radiation from the sun has an albedo affect where it reflects of the icy and snowy surface

What is the Coriolis effect?

The middle parts of the earth spin faster than the poles, making winds move in a curved and eastern direction towards the northern hemisphere

What is a drainage basin?

The area of land surrounding a river, from which the river receives water and subsequently drains this water.

What is precipitation?

rain, snow, sleet, or hail

What is infiltration?

When water enters the ground

What is interception?

Water being prevented from reaching the surface by trees and plants

What is stem flow?

Water running down a plant stem or tree trunk

What is overland flow?

water that flows over land

What is through flow?

movement of water through soil

What is transpiration?

evaporation of water from plant leaves

What is evapotranspiration?

Water rises as vapour from the ground or is released from leaves

What is ground water?

Water deep in the ground

What is soil water?

Water held between soil particles

What is groundwater flow?

Movement of water down through the ground

What is percolation?

The slow movement of ground water

What is surface storage?

Water stored in lakes, ponds and puddles

What is ground water storage?

Water stored underground in bed rock

What is the drainage basin system?

What is the formula for water balance?

Precipitation = discharge + evapotranspiration +/- changes in storage

P = Q + E +/- S

What is water balance?

when water intake equals water output

What happens to the water balance in wet seasons?

Greater precipitation that evapotranspiration created water surplus

-> ground stores fill with water = increased surface runoff , higher discharge + higher river levels = positive water balance

What happens to the water balance in drier seasons?

Evapotranspiration exceeds precipitation

-> plants absorb water leading to ground stores being depleted

-> water deficit at end of dry season

What causes variations in runoff? (Physical)

• time of year/ season -> growth of vegetation = increased rated of evapotranspiration + interception

• type of vegetation -> broad leaved trees will intercept greater amounts of vegetation + in summer there are more leaves on deciduous trees = higher interception and peak discharge is lower

• antecedent rainfall -> heavy rain falling on already saturated soil from previous period of wet weather = rapid runoff

What causes variations in runoff? (Human)

• urbanisation

  • reduced infiltration through use of impermeable surfaces increases runoff

  • drains and seers transport water rapidly to rivers increases surface run of

  • deforestation -> reduces interception , evapotranspiration and protective canopy layer = increased rates of infiltration and result in the saturation capacity being reached quickly

What is the River Wye case study in Wales?

• upper part of basin is steep slopes, acidic soils and grassland and deforestation to make more room for sheep grazing which reduces interception and increases overland flow

• ditches dug to drain land to make it more productive and increase speed of water transfer

• impermeable rocks in upper river basin = groundwater flow is limited and soils quickly saturated

What is river discharge?

The volume of water that flows in a river per second

How do you calculate river discharge?

Cross section area of water (m^2) x speed (m/s) = river discharge (m^3/s in cumecs)

What is river discharge affected by?

The amount or volume of water

More water means more is flowing past you which means more discharge

What is a river regime and how can it be changed?

It is the annual variation in the discharge or flow of a river at a particular point and is usually measured in cumecs

Changed by:

precipitation , temp , evapotranspiration and drainage basin characteristics

What is base flow?

The normal day to day discharge of the river and is the consequence of groundwater seeping into the river channel

What is bank full discharge?

The maximum discharge that a particular river channel is capable of carrying without flooding

How can you tell if a hydrograph is flashy?

Short lag time

Steep rising limb

Much higher peak discharge

why does water get into the river quickly after the rainfall event?

Because of:

Deforestation

Saturated soils

Impermeable bedrock = no percolation

How can you tell if a hydrograph is subdued?

Long lag time

Gentle rising limb

Much lower peak discharge

Why does water get to the river slowly after the rainfall event?

Because of:

Afforestation

Unsaturated soils

Permeable rock allowing percolation

What are the positive impacts of soil drainage?

• increases ease which the soil can be warmed = possible earlier sowing if seeds = improved germination

• Improved aeration = conditions more favourable for microorganisms to thrive

• Makes it easier to achieve greater root penetration, enabling roots to grow faster and further

What are the negative impacts of soil drainage?

• topsoil can dry out in periods of low rainfall

• Changes the amount of water reaching rivers and the speed which it gets there

• The discharge in rivers become more flashy and peak discharges increase making flooding more likely

What has happened the the Aral Sea in Asia?

• it uses the be the largest lake in the world, however only 10% of it is left

• The 2 biggest rivers of Central Asia were used to feed the Aral Sea but were dammed to allow for irrigation

• The Bugun village was found on the shore of the Aral Sea, but is now found 9 miles away from it

What is London’s aquifer problem?

• industrialization from the 1800s to 1960s led to the increase in exploitation of the groundwater sources

• this has caused recession in the groundwater levels in London

• However in some areas of London, there has been a significant recovery in the aquifer due to water dependant industries moving

• But, this has threatened some of London landmarks, e.g London Underground

Who manages the water levels in London?

But the General Aquifer Research, Development and Investigation Team

• west London seen increase of 4-8 metres a year since 2000

What has happened in the Mekong Delta in Vietnam?

• thousands of hectares of farmland and crops are being threatened due to salt water incursion occurring

• Over abstraction of these coastal wells mean droughts are occurring, causing up to 60km of incursion inland

What is the landscape like in the upper catchment of the River Ouse?

• it has lots of heather moorland

• The ground is often saturated and full of sphagnam moss which holds lots of water

• The landscape was drained post WW2 to grow grass for sheep grazing and wheat

Where is the river Ouse?

• in the north of England

• Covers most of Yorkshire dales and vale of York

• The river enters the North Sea via the number estuary

• There are 4 major river systems forming the Ouse

What is the geology at the River Ouse?

• upper valley made of old permeable rock (limestone)

• There is a lot of clays which are impermeable

What is vegetation like at the River Ouse?

• low interception rates from the heathers in the upper basin

• Areas of scattered coniferous trees offer better interception

How is the land used at the River Ouse?

• the catchment area covers districts of Leeds, Selby, York etc

• Urban land occupied 2.2% of catchment area → vital to regional economy as York and Harrogate fall in the ‘golden triangle’ as they are a commuter district for Leeds

What are the flood defences in York?

• Clifton Ings → embankments surround the river, increasing capacity of river

• Almery Terrace → concrete flood walls with rubber sealed gates to protect the houses

• River channelisation → river been straightened so water moves through efficiently

Why does York have a high flood risk?

The landscape in York is very flat and low, meaning flood water easily spreads

What are the predicted impacts of climate change on the future related to flood risk?

• more frequent and intense storm, causing more regular flooding

• Increased winter rainfall, increasing likelihood of large scale flood events

What are the 3 forms of carbon?

• solid form → when stored in living things, minerals of rocks, soil and ice

• Liquid form → when carbon dissolved in water, in form of carbonic acid

• Gaseous form → when carbon combines with oxygen to form CO2 and other elements to form gases like methane

What are the main stores of carbon?

lithosphere , hydrosphere , cryosphere , atmosphere , biosphere

What is carbon sink and carbon store?

Carbon sink ~ a store that absorbs more carbon than it releases

Carbon source ~ releases more carbon than it absorbs

What is carbon measured in?

Gigatonnes (GtC)

How does the lithosphere store carbon?

• biggest store of carbon (99.9%)

• Stores carbon in rocks like limestone and chalk and in fossilized organic matter (coal, oil, gas)

How does the biosphere store carbon?

• stores around 3,170 GtC

• Stores carbon in vegetation , plant litter and little in animals

• Plants and animals release carbon when they decompose

How does the pedosphere store carbon?

• is partly the biosphere and lithosphere

• Stored around 950 GtC (little amount)

• Stores carbon in organic matter in soils , peat which stores around 250 GtC

How does the atmosphere store carbon?

• Carbon only takes up 0.04% of atmosphere

• CO2 + water vapour = carbonic acid = weathering

• 2022 CO2 levels = 413 ppm

• 2013 CO2 levels = 400ppm

• 1958 CO2 levels = 317 ppm

• start of industrial rev = 280ppm

How does the cryosphere store carbon?

• carbon mostly stored here in permafrost and tundra

• Permafrost is carbon sink and stores around 1600 GtC