OCR A Level ELSS - Entire Course 1

Question 1

Importance of water on earth?

Answer 1

-oceans moderate temperatures by absorbing, storing and slowly releasing heat
-clouds reflect incoming solar radiation and lower surface temperatures
-water vapour absorbs long wave radiation from the earth and maintains global temps 15 degrees higher than they usually would be

Question 2

Uses of water on Earth?

Answer 2

-Makes up 65-95% of living organisms and is vital for their growth, reproduction and metabolic functioning
-plants need water for photosynthesis, respiration and transpiration.
-water is used in all chemical reactions in humans and animals.
-important economic resource, used in agriculture, food manufacturing and to generate electricity.

Question 3

Importance of carbon on earth?

Answer 3

-Life is carbon based, built on large molecules such as proteins, carbohydrates and nucleic acids.

Question 4

Uses of carbon on Earth?

Answer 4

-economic resource, used in fossil fuels which power global economy
-agriculture, crops and forest trees store lots of carbon, used by humans for food, timber, paper, etc.

Question 5

why is earth the only planet able to support life?

Answer 5

-climate - temperatures do not go from one extreme to the other
-light - all plants receive light from the sun which they need in order for photosynthesis
-atmosphere - breathable atmosphere, 21% oxygen and small amounts of CO2 (0..04%), atmosphere is kept on earth by gravity
-water - most important chemical needed to sustain life, drinkable and not acidic
-sun - in Goldilocks zone, right amount of heat and light to support life

Question 6

spheres of the earth

Answer 6

-atmosphere (gas envelope surrounding the earth)
-biosphere (space between earth + atmosphere occupied by living organisms)
-lithosphere (crust + upper mantle, divided into tectonic plates)
-cryosphere (frozen part of earths surface)
-hydrosphere (all water on earths surface)

Question 7

What is the Goldilocks zone?

Answer 7

-its ‘just the right distance’ from the sun to allow the presence of liquid water on earth

Question 8

At a global scale, water and carbon flow in __________ systems (driven by the sun’s energy) between the ________________, the oceans, land and the _____________.

Answer 8

-closed
-atmosphere
-biosphere

Question 9

The global water cycle consists of 3 main stores: the ______________, oceans and land. The oceans are the _____________ store and the atmosphere is the ______________.

Answer 9

-atmosphere
-biggest
-smallest

Question 10

Water moves between stores by….

Answer 10

precipitation, evapotranspiration, run-off and groundwater flow.

Question 11

Long term storage in sedimentary rocks holds…

Answer 11

99.9% of all carbon on earth.

Question 12

Carbon in circulation moves rapidly between the…

Answer 12

atmosphere, the oceans, soil and the biosphere.

Question 13

The main pathways between stores in the carbon cycle include…

Answer 13

photosynthesis, respiration, oxidation (decomposition, combustion), and weathering.

Question 14

Systems are…

Answer 14

groups of objects and the relationships that bind the objects together

Question 15

At smaller scales (drainage basin or forest ecosystem), ___________ as well as the sun’s energy cross system boundaries. These systems are….

Answer 15

-materials
-open systems

Question 16

Sizes of stores of water?

Answer 16

Oceans- 97%
Ice caps + sheets- 2%
Groundwater- 0.7%
Lakes- 0.01%
Soils- 0.005%
Atmosphere- 0.001%
Rivers- 0.0001%
Biosphere- 0.00004%

Question 17

Sizes of stores of carbon?

Answer 17

-Sedimentary rock- 60-100 million GT
-Ocean deep layer- 38,000 GT
-Fossil fuels- 4,130 GT
-Soil- 2300 GT
-Ocean surface- 700 GT
-Atmosphere- 600 GT

Question 18

How much water does the global water circulate per year?

Answer 18

505, 000 km3 per year between stores

Question 19

Inputs and outputs of water in the water cycle?

Answer 19

1)EVAPOTRANSPIRATION- water evaporates from surface water and land surface, and is transpired through leaves of plants
2)CONDENSATION + PRCIPITATION- occurs in atmosphere, vapour becomes liquid and is transferred to land as precipitation
3)ABLATION + SUBLIMATION- occurs when snow or ice melts, and sublimation occurs when ice turns into water vapour.
4)RUN OFF + FILTRATION - water runs off land surface into rivers, precipitation ends up as run off after infiltration in soil.
5)PERCOLATION- transfer of water to ground water stores (aquifers), returned to earth surface as springs.

Question 20

Inputs + outputs of carbon in the carbon cycle?

Answer 20

1)PRECIPITATION-atmospheric CO2 dissolves in rainwater to form a weak carbonic acid, when precipitation happens CO2 flows back to lands and oceans- increased burning of fossil fuels increases acidity of rain + ocean water.
2)PHOTOSYNTHESIS - process by plants and phytoplankton, CO2 + water converted into glucose + oxygen, chemical energy stored in tissues
3)WEATHERING - involves the breakdown of rocks near earths surface by physical, mechanical and biological processes
4)RESPIRATION - process where glucose is converted back into carbon dioxide + water
-plants and animals absorb oxygen to burn carbohydrate stores to provide energy for metabolism and growth
5)DECOMPOSITION - carbon released as CO2 when organisms die by microorganisms carrying out respiration which also put mineral ions into soil
6) COMBUSTION - when organic material burns, CO2 locked up in the material is released with other gases like SO2

Question 21

Evapotranspiration?

Answer 21

The evaporation of water from soil plus the transpiration of water from plants.

Question 22

sublimation?

Answer 22

when ice turns into water

Question 23

ablation?

Answer 23

when glacial ice or sheets melt to release water

Question 24

infiltration?

Answer 24

Downward movement of water through soil.

Question 25

run off?

Answer 25

water flowing off the land into bodies of surface water (for example, lakes or rivers).

Question 26

what is water balance?

Answer 26

the relationship between precipitation, stream flow, evapotranspiration, soil moisture and ground water storage in a drainage basin over a year

Question 27

The principal flows in the water cycle that link the various stores are:

Answer 27

precipitation, evaporation, transpiration, run-off, infiltration, percolation and throughflow.

Question 28

percolation?

Answer 28

The downward movement of water through soil and rock due to gravity. -Goes deep underground into an aquifer. -Returned to earth's surface as springs.

Question 29

water cycle budget?

Answer 29

the annual volume of movement of water by precipitation, evapotranspiration, run-off etc. between stores such as oceans, permeable rocks, ice sheets, vegetation, soil, etc.

Question 30

through flow?

Answer 30

A horizontal movement of water through the soil to rivers or oceans

Question 31

base flow?

Answer 31

Water input to streams and rivers from natural reservoirs such as aquifers, pear bogs, soils etc.

Question 32

interception loss?

Answer 32

rainwater stored temporarily on the leaves, stems and branches of vegetation which is evaporated and does not reach the ground surface

Question 33

water balance equation?

Answer 33

precipitation = evapotranspiration + streamflow +/- storage

Question 34

Process of the water cycle: Evaporation?

Answer 34

Requires a lot of energy to change state from liquid to vapour

Question 35

Process of the water cycle: Transpiration?

Answer 35

Transfer of water from plants to the atmosphere (10% of atmospheric water originates from transpiration). -Influenced by temperature, wind speed and water availability to plants.

Question 36

Process of the water cycle: Precipitation?

Answer 36

-Water and ice that falls from clouds. -Forms when vapour in the atmosphere cools to its dew-point temperature and condenses into tiny water droplets to form clouds. -These droplets then aggregate, reach a critical size and leave the cloud as precipitation.

Question 37

Process of the water cycle: Condensation?

Answer 37

Change of water vapour to liquid, occurs when air is cooled to its dew point and clouds form.

Question 38

4 ways that cause clouds to form?

Answer 38

Clouds form when moist air cools. 1)Air warmed by contact with ground or sea surface, rises through the atmosphere (convection). As the air rises and pressure falls it cools by (adiabatic) expansion. 2) Warm air mass meets cold air mass = forms stratus and cumuliform clouds 3) Large air mass moves across cooler surface = stratus 4) Air is forced to rise over elevated land (hills), causing it to cool.

Question 39

Cumuliform clouds?

Answer 39

-flat bases, vertical development -form when air is heated by the Earth's surface -causes air parcels to rise freely in the atmosphere, as the parcel of air cools and expands due to decreasing pressure, dew point is reached.

Question 40

Stratiform clouds?

Answer 40

-Form when an air mass moves across a cooler surface (ocean). This is called advection. -Low, white, little rainfall

Question 41

Cirrus clouds?

Answer 41

-short, wispy clouds - form at high altitude, consist of ice crystals. -form after a warm front where air masses reach high levels -do not produce rain, no impact on water cycle.

Question 42

Condensation near the ground surface produces ______ and fog. Both deposit large amounts of moisture on ______________.

Answer 42

-dew -vegetation

Question 43

Lapse rates...

Answer 43

Describe the vertical distribution of temperature in the lower atmosphere, and the temp changes that occur within an air parcel as it rises vertically from the ground.

Question 44

What causes air to reach its water holding capacity (dew point)?

Answer 44

1) the amount of water in the air increases, and air cannot hold any more water 2)the air has cooled to its dew point, air cannot hold any more water

Question 45

dew point

Answer 45

The temperature at which condensation begins

Question 46

the two main sinks of carbon?

Answer 46

-sedimentary rocks - 60-100 million GT - 99.9% of the carbon store -ocean deep layer - 38,000 GT - 2nd biggest store

Question 47

what is GT - carbon store measurement?

Answer 47

billion tonnes

Question 48

Describe the slow carbon cycle

Answer 48

-involves the long term store of carbon -CO2 dissolves from atmosphere into ocean where marine organisms (shell fish and phytoplankton) make their shells and skeletons -by fixing calcium and carbon to form calcium carbonate -when they die, they accumulate on the ocean floor and over millions of years become compressed to form carbon rich sedimentary rock -carbon stored in rock for 150 million years -oceanic rock containing sedimentary rock is sub-ducted, causing it to melt and carbon is released during volcanic eruptions -sedimentary rock on surface releases carbon when weathered

Question 49

describe the fast carbon cycle

Answer 49

-transfer between stores is 10x faster than the slow carbon cycle -land plants and microscopic phytoplankton in oceans are the key components -absorb CO2 during photosynthesis, transforming it into carbohydrates stored in their tissues -during respiration they release CO2 into the atmosphere by evaporation

Question 50

sedimentary rock

Answer 50

-A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together

Question 51

the water and carbon cycle at global scales?

Answer 51

-considered as closed systems which are driven by the suns energy which is external to the earth and only energy crosses the boundaries / not matter -carbon and water flow between atmosphere, oceans, land and biosphere

Question 52

the water and carbon cycle at local scales?

Answer 52

-considered as open systems as materials and energy both cross boundaries -ex = drainage basin or forest ecosystem

Question 53

main processes of the water cycle?

Answer 53

-evaporation -transpiration -condensation

Question 54

main inputs and outputs of water in the water cycle

Answer 54

-evaporation and transpiration -ablation, sublimation, condensation, precipitation -run off and infiltration -percolation

Question 55

what does residence time mean?

Answer 55

the length of time a molecule of water or carbon remains in natural storage

Question 56

what are phytoplankton?

Answer 56

tiny photosynthesising marine organisms in surface waters of oceans

Question 57

carbon cycle and precipitation?

Answer 57

-atmospheric CO2 dissolves in rainwater to form a weak carbonic acid -when precipitation happens carbon flows back to lands and oceans -as CO2 concentrations have increased in the atmosphere due to humans burning more fossil fuels, the acidity of precipitation has increased -leading to acidity of ocean water

Question 58

carbon cycle and photosynthesis?

Answer 58

-process used by land plants and phytoplankton to convert light energy into chemical energy -CO2 + H20 - O2 + GLUCOSE -chemical energy is stored in carbohydrate molecules such as sugars which plants use to maintain growth, reproduction and respiration -glucose used as building block for cell walls, for respiration in plant cells and as an energy store

Question 59

carbon cycle and weathering?

Answer 59

-involves the breakdown of rocks, near the surface by physical, mechanical and biological processes -chemical weathering involves rainwater thats a weak carbonic acid which weathered rocks through carbonation or solution -as the rock reacts with the carbonic acid it forms calcium bicarbonate which is soluble -running water releases carbon into rivers and oceans -physical weathering does not involve any altering of the carbon composition -biological weathering involves chelation (organic acids) - as organic material decomposes it makes the soil become acidic which attacks rock minerals

Question 60

carbon cycle and respiration?

Answer 60

-the process where carbohydrates formed in photosynthesis are converted into CO2 + water -plants and animals absorb oxygen which allows them to burn carbohydrate store to provide energy needed in metabolism + growth -respiration + photosynthesis are elements of the fast carbon cycle

Question 61

carbon cycle and decomposition?

Answer 61

-carbon is released as CO2 when living organisms die and are decomposed by microorganisms -decomposer organisms release CO2 into the atmosphere and extract mineral nutrients from the soil -rates of decomposition depend on climatic conditions, which are faster in warm, humid environments

Question 62

carbon cycle and combustion?

Answer 62

-when organic material burns, carbon locked up is released which other gases like SO2 -combustion can happen naturally by wildfires which are caused by lightening strikes -benifical to ecosystem as it leads to an increase in nutrients and carbon cycling, leading to more growth -due to a long winter, forest litter can build up on the forest floor therefore a fire releases the jam with nutrients and opens up the candy to create new habitats and increase biodiversity -combustion happens due to humans actions for example deliberate firing of forests or grassland to clear space for cultivation or improve grazing quality

Question 63

what is Catchment Hydrology?

Answer 63

Water studies within a drainage basin

Question 64

what is a water basin?

Answer 64

a region drained by a river or its tributaries

Question 65

catchment hydrology - 2 processes?

Answer 65

-evaporation -interception -

Question 66

catchment hydrology - evaporation?

Answer 66

-evaporation is the phase when liquid water is converted into vapour -heat energy is required break molecular bonds of water which is absorbed as latent heat and released later in condensation -process allows huge amounts of heat to be transferred around the planet, for example from the tropics to the poles

Question 67

catchment hydrology - interception?

Answer 67

-vegetation intercepts a proportion of precipitation storing it temporarily on branches, stems and leaves -eventually this moisture evaporates or falls to the ground -throughfall is when water is intercepted before dripping to the ground -stemflow occurs during prolonged periods of rainfall when intercepted water may flow along branches and stems

Question 68

factors effecting interception loss?

Answer 68

-interception storage capacity - as vegetation becomes saturated, output of water through stem flow and through flow increases -wind speed - evaporation rates increase with wind speed -vegetation type - larger surface areas (trees) have a larger interception losses than grasses -tree species - some species have leaves all year round, some do not

Question 69

infiltration, through flow, ground water flow and run off?

Answer 69

-rain falling to the ground and not entering storage follows one of two paths 1-infiltration by gravity into the soil and lateral movement to through flow to stream or river channels 2-overland flow across the ground surface as a sheet or as trickles to stream or river channels -a few ideas explain the two paths, one is overland flow due to infiltration capacity -second idea is due to rainfall always infiltrating the soil

Question 70

what pattern does ground water stores follow?

Answer 70

-by late October the water table is beginning to rise as temperatures and evapotranspiration fall -recharge continues until late January -groundwater levels then decline throughout late winter, spring and summer, reaching their lowest point in early autumn

Question 71

Cryospheric processes

Answer 71

-ablation is loss of ice from snow, ice sheets and glaciers due to a combination of melting, evaporation and sublimation -meltwater is an important component of river flow in high latitudes and mountain catchments in spring and summer -rapid thawing of snow in winter is a common cause of flooding in adjacent lowlands

Question 72

physical (inorganic) pump?

Answer 72

-involves mixing of surface and deep ocean waters by vertical currents -creates a more even distribution of carbon in oceans -CO2 diffuses into the oceans from atmosphere -surface currents transport dissolved CO2 polewards where it becomes dense and sinks (downwelling) -individual carbon particles may remain deep in the ocean for many centuries -eventually deep ocean currents transport carbon back up to the surface (upwelling) -cold, carbon rich waters rise to the surface where CO2 diffuses back into the atmosphere

Question 73

biological (organic) pump?

Answer 73

-50% of carbon fixation happens by photosynthesis in oceans -50GT of carbon is drawn from atmosphere by biological pump each year -marine organisms (phytoplankton) drive the pump -phytoplankton floating near surface combine sunlight, water and CO2 into organic material -whether consumed in the food chain or through natural death, carbon locked in phytoplankton accumulates on the ocean floor or is decomposed and released as CO2. or is used by organisms for shells and skeletons -most CO2 ends up in sediments such as chalk and limestone

Question 74

What is permafrost?

Answer 74

a thick subsurface layer of soil that remains frozen throughout the year, occurring chiefly in polar regions.

Question 75

what is the active layer?

Answer 75

-The top layer of permafrost. -melts

Question 76

water cycle negative feedback loop

Answer 76

heavy rainfall = increased water infiltration = more water stored in aquifers = water table is raised = more water is returned to the surface as springs = water table returns to normal levels

Question 77

carbon cycle negative feedback loop

Answer 77

burning of fossil fuels = increased atmospheric CO2 = photosynthesis stimulated = more CO2 removed form the atmosphere = CO2 levels restored

Question 78

3 land use changes?

Answer 78

1. urbanisation 2. farming 3. forestry

Question 79

land use changes - urbanisation?

Answer 79

-farmland and woodland areas replaced by tarmac and brick -artifical surfaces are impermeable and allow little water infiltration and provide minimal water storage capacity, giving rise to run off -urban areas have drainage systems designed to remove water rapidly (gutters, pitched roofs) therefore water form precipitation flows quickly into streams and rivers, leading to a rapid rise in the water tables -urbanisation also encroaches floodplains which are natural water stores -overall, urbanisation reduces water storage capacity in drainage basins, increasing river flow and flood risks

Question 80

land use changes - farming and the carbon cycle?

Answer 80

-clearance of forest for farming reduces carbon storage in above and below ground biomass -soil carbon storage is reduced by ploughing and exposure of organic material to oxidation -harvesting of crops returns only a small amount of organic matter to the soil -soil erosion by wind and soil is most severe when crops have been lifted and have little protective cover -carbon exchanges through photosynthesis are lower due to a lack of biodiversity and a short growth cycle

Question 81

land use changes - farming and the water cycle?

Answer 81

-crop irrigation diverts surface water from rivers and groundwater to cultivated land -interception of crops is less than of grasslands, -evapotranspiration is reduced by crops -ploughing increases evaporation and soil moisture loss -heavy machinery compacts the soil which leads to more surface run off leading to peak flows higher in farmland ecosystems -ploughing causes infiltration which means even more water is transferred to streams and rivers

Question 82

land use changes - forestry plantations and the water cycle?

Answer 82

-there is a higher rate of rainfall interception in natural plantations -preferred plantation species in the uk are conifers with needle like structures, evergreen habit and high density -increased evaporation form water stored on leaf surfaces -reduced run off and stream discharge due to high interception and transpiration rates -clear felling of harvest timber creates a sudden change in the water cycle, increasing run off, reducing evapotranspiration and increasing stream discharge

Question 83

land use changes - forestry plantations and the carbon cycle?

Answer 83

-in the uk a typical plantation contains 10x more carbon than grassland and 20x higher than heathland -soil represents a large carbon pool - 500 tonnes/ha -forest trees extract carbon for hundreds or years only after 100 years since planting -balanced by litter inputs into the soil

Question 84

what were the CO2 levels in the atmosphere 800,000 years ago compared to today (2016)?

Answer 84

-260 ppm 800,000 years ago -400.5 ppm 2016 -small changes over 800,000 years due to glacials and interglacials

Question 85

what were the CO2 levels in the atmosphere in 1700 compared to 2016?

Answer 85

-most people lived in rural areas in 1700 -1800 - the industrial revolution and CO2 levels rapidly increased due to coal use -1910 - the first production line car -1913 - coal extraction -1960 - increase in car use and central heating fitted in homes -1700 - 310 ppm -2016 - 400.5 ppm

Question 86

changes in the CO2 levels in the past two years?

Answer 86

-400.5 ppm -in spring and summer there is less CO2 in the atmosphere due to more vegetation therefore increased photosynthesis -in winter there is increases in CO2 due to more use of heating inn homes -increased in 5 ppm in two years

Question 87

energy consumption overtime?

Answer 87

-oil (496 GT) and coal (673 GT) are the largest carbon emission sources -coal has been used since the industrial revolution and oil has been used since 1920s -since 1970s there has been an increase in use of nuclear and hydroelectric sources -overall global energy consumption has increased rapidly since the 1960s with coal and oil being the main sources

Question 88

3 stages involved in CCS?

Answer 88

1. separate CO2 from power station emissions 2. CO2 is compressed and transported to storage areas 3.injected into porous rock underground and stored permanently

Question 89

what is the impact and plans of CCS?

Answer 89

-plays an important role in reducing CO2 and other emissions -in USA, 40% of all carbon emissions could be reduced by 80-90% -in the UK a CCS project is underway in peterhead, north east Scotland which is going to capture 2 million tonnes of CO2 -plan for carbon to be transported by pipeline to the North Sea and stored in depleted gas resevoirs

Question 90

Why is the CCS limited?

Answer 90

-involves big capital costs -uses large amounts of energy (compress and transport CO2) -requires storage in specific geological locations

Question 91

in 2013 what percentage did fossil fuels account for the overall energy consumption?

Answer 91

87% fossil fuels

Question 92

what sources were used the most in 2013 for global energy consumption?

Answer 92

-oil (37%) -natural gas (27%) -coal (23%)

Question 93

where have most of our carbon emissions come from (1750 - 2012)?

Answer 93

-coal - 673GT -land use - 590GT

Question 94

where have our carbon emissions gone (1750 - 2012)?

Answer 94

-atmosphere (879GT) -ocean (590GT) -land (528GT)

Question 95

how many tonnes of CO2 is released into the atmosphere annually?

Answer 95

-10 billion tonnes -increases the CO2 concentration over 1 ppm

Question 96

impact of anthropogenic carbon emissions in the atmosphere?

Answer 96

-since 1750, 879GT of anthropogenic co2 emissions have remained in the atmosphere, tasing co2 concentrations from 280 ppm - 400 ppm -co2 levels today have been the highest for 800,000 years

Question 97

what is the impact of anthropogenic carbon emissions?

Answer 97

-compromise only 10% of the natural influx of from the biosphere, oceans and atmosphere -however they impact significantly on carbon stores -despite international efforts used to reduce carbon emissions, between 2000 and 2009 they grew faster than in any other decade -without increased absorbtion of CO2 from oceans and biosphere, atmospheric concentrations would exceed 500 ppm

Question 98

groundwater

Answer 98

water stored underground in permeable and porous rocks know as aquifers

Question 99

aquifer

Answer 99

a water bearing band of porous or permeable rock

Question 100

artesian aquifer

Answer 100

a confined aquifer containing groundwater under pressure, which will rise to the surface under its own pressure

Question 101

artesian pressure

Answer 101

The hydrostatic pressure exerted on groundwater in a confined aquifer occupying a synclinal structure.

Question 102

abstraction

Answer 102

the extraction of water from rivers and boreholes for public demand

Question 103

impact of water extraction?

Answer 103

-rates of extraction have exceeded rates of discharge -lower flows have reduced flood risk and temporary areas of standing water on floodplains -lower groundwater levels ave caused springs to dry up and reduce the instance of saturated overground flow on chalk

Question 104

the water table?

Answer 104

-the level below which the ground is saturated with water.

Question 105

changes that occur in the water table levels?

Answer 105

-water table heights fluctuate seasonally by periods of lots of rainfall, drought and abstraction -in normal years in southern England, the water table falls between march and September due to rising temperatures and increased evapotranspiration -recharge resumes in late autumn

Question 106

artesian basins

Answer 106

-when sedimentary rock forms a syncline, a downloaded basin like geological structure -confined between layers of impermeable rock (clay) -may contain groundwater under artesian pressure -when groundwater is tapped by a well or borehole water will flow to its surface under its own pressure

Question 107

what is remote sensing?

Answer 107

the scanning of the earth by satellite or high-flying aircraft in order to obtain information about it.