Water and Carbon Flashcards
(76 cards)
1
Q
inputs definition
A
when matter or energy is added to a system
2
Q
outputs definition
A
when matter or energy leaves the system
3
Q
stores/components definition
A
where matter of energy builds up
4
Q
flows/transfers definition
A
when matter or energy more from one store to another
5
Q
boundaries definition
A
the limits of the system
6
Q
open systems
A
both energy and matter can enter and leave an open system, there are inputs and outputs of both
e.g. drainage basins, energy from the sun enters and leaves the system, water is input as precipitation and output as river discharge into the sea
7
Q
closed systems
A
matter cant enter or leave, can only cycle between stores
energy can enter or leave
e.g. carbon cycle, energy is input from the sun through photosynthesis and output through respiration but the amount of carbon on earth stays the same because there are no inputs or outputs of matter
8
Q
equilibrium
A
when the inputs and outputs of a system are balanced
9
Q
dynamic equilibrium
A
lots of small variations between inputs and outputs in a system but they are small so they remain balanced on average
large long term changes to the balance of inputs and outputs can cause a new system to change and establish a new dynamic equilibrium
10
Q
positive feedback
A
amplifies the change in inputs or outputs
the system responds by increasing the change, moving the system even further from its previous state
e.g.: temp rise, ice melts, less ice=less of the sun’s energy is reflected, more energy absorbed by earth…repeat
11
Q
negative feedback
A
counteracts the change in inputs or outputs
the system responds by decreasing the effects of the change, keeping the system closer to its previous state
e.g. co2 emitted, co2 in the atmosphere increases, causes plant growth to increase, plants remove and store co2,, co2 in atmosphere reduces
12
Q
subsystems
cryosphere
A
all the parts of the earth system where its cold enough for water to freeze e.g. glacial landscapes
13
Q
subsystems
lithosphere
A
outermost part of the earth, includes crust and upper mantle
14
Q
subsystems
biosphere
A
part of the earth’s systems where living things are found, includes all living parts of the earth including plants, animals, birds, fungi, insects, bacteria etc
15
Q
subsystems
hydrosphere
A
all of the water on earth
liquid, solid or gas
saline or fresh
16
Q
subsystems
atmosphere
A
the layer of gas between earth’s surface and space, held in place by gravity
17
Q
subsystems definition
A
the earth system broken down
all interlinked
matter and energy move between subsystems, the output of one is the input of the next etc: cascading system
changes that occur in one subsystem can effect what happens in others
18
Q
percentage of saline water
A
97%
19
Q
freshwater distribution
A
only 3% of earth's water is freshwater 69% frozen in cryosphere 30% groundwater 0.3% liquid freshwater 0.04% stored as water vapour in the atmosphere
20
Q
water cycle
stores
A
cryosphere: glaciers, ice caps
groundwater and lithosphere
liquid water: oceans, lakes, rivers
atmosphere: clouds, water vapour
21
Q
the magnitude of stores
A
the amount of water present in each store varies over a range of scales from local, e.g. hillslope to drainage basin to global
22
Q
processes driving change in the magnitude of stores
evaporation
A
occurs when liquid changes to gas, gains energy from solar radiation
increases the amount of water in the atmosphere
magnitude of evaporation varies by location and season:
lots of solar radiation, large supply of water and warm dry air then evaporation is high
not much solar radiation, little water and cool air that is already nearly saturated then evaporation will be low
23
Q
processes driving change in the magnitude of stores
condensation
A
when water vapour becomes a liquid, loses energy to surroundings
happens when air containing water vapour cools to dew point, e.g. at night
water droplets can stay in the atmosphere or flow to other subsystems which would decrease the amount of water stored in the atmosphere
magnitude of condensation flow depends on amount of water vapour in atmosphere and temperature:
lots of water + rapid drop in temp = high condensation
24
Q
processes driving change in the magnitude of stores
cloud formation and precipitation
A
precipitation is the main flow of water from atmosphere to ground
clouds form when warm air cools down, causing water vapour in it to condense into water droplets which gather as clouds and when the drops get big enough they fall as precipitation
water droplets caused by condensation are too small to form clouds on their own, for clouds to form there has to be tiny particles of other substances e.g. dust or soot that act as cloud condensation nuclei, they give water a surface to condense on. this encourages clouds to form rather than allowing the moist air to disperse
25
processes driving change in the magnitude of stores
| cryospheric processes
accumulation (input) and ablation (output)
change the amount of water stored in the cryosphere
the balance of accumulation and ablation varies with temperature
during periods of global cold inputs into the cryosphere are greater than outputs, water is transferred to it as snow and less water is transferred away due to melting, during warmer global temperatures the magnitude of the cryosphere reduces as losses due to melting are larger than inputs of snow
variations in cryospheric processes happen over different timescales, there are the changes in global temperature that happen over thousands of years but they can also happen over shorter timescales such as annual temperature fluctuations when more snow falls in winter than summer
26
drainage basins as natural systems
open, local hydrological cycles
a drainage basin is the area surrounding the river where the rain falling on the land flows into that river, also known as the rivers catchment
the boundary of the drainage basin is the watershed, any precipitation falling beyond this point enters a different drainage basin
water comes into the system as precipitation and leaves via evaporation, transpiration and river discharge
27
drainage basins
| inputs
precipitation, includes all the ways moisture comes out of the atmosphere
rain, snow, hail, dew and frost
28
drainage basins
| storage
1) interception: when precipitation lands on vegetation or other structures before it reaches the soil. creates a significant store of water in wooded areas, only temporary because the water collected may evaporate quickly or fall from the leaves as throughfall
2) vegetation storage: water taken up by plants, all the water contained in plants at any one time
3) surface storage: incldues water in puddles, ponds and lakes
4) soil storage: includes moisture in the soil
5) groundwater storage: water stored in the ground either in soil or rocks. the water table is the top surface of the zone of saturation. porus rocks that hold water are called aquifers
6) channel storage: water held in a river or stream channel
29
drainage basins
| flows
1) infiltration: water soaking into the soil, infiltration rates are influenced by soil type, soil structure, and how much water is already in the soul
2) overland flow: water flowing over the land, happens because water is falling faster than infiltration
3) throughfall: water dripping from one leaf to another
4) stemflow: water running down a plant stem or tree trunk
5) throughflow: water moving slowly downhill through the soil, faster through 'pipes' (cracks in the soil or animal burrows)
6) percolation: water seeping down through soil into the water table
7) groundwater flow: water flowing slowly below the water table through permeable rock, permeable=faster, e.g. limestone
8) baseflow: groundwater flow that feeds into rivers through river banks and river beds
9) interflow: water flowing downhill through permeable rock above the water table
10) channel flow: water flowing in the river or stream itself (river discharge)
30
drainage basins
| outputs
1) evaporation: water turning into water vapour
2) transpiration: evaporation from within leaves, plants and trees take up water through their roots and transport it to their leaves where it evaporates into the atmosphere
3) evapotranspiration: the process of evaporation and transpiration together
4) river discharge/river flow
31
the water balance
worked out from inputs (precipitation) and outputs (channel discharge and evapotranspiration)
affects how much water is stored in the basin
the water balance in the uk shows seasonal patterns
1) wet seasons precipitation exceeds evapotranspiration which creates a water surplus, ground stores fill with water so there is more surface run off and higher discharge so river levels rise
2) drier seasons precipitation is lower than evapotranspiration so ground stores are depleted as some water is used and some flows into the river channel but isnt replaced by precipitation
3) at the end of a dry season there's a deficit of water in the ground, the ground stores are recharged in the next wet season
32
the flood hydrograph
river discharge is the volume of water in cubic metres the flows in a river per second
high levels of runoff increase discharge of a river
hydrographs are graphs of discharge over time, they show how the volume of water flowing at a certain point in a river changes over a period of time
flood/storm hydrographs show river discharge around the time of a storm event, they only cover a relatively short time period.
33
the flood hydrograph
river discharge is the volume of water in cubic metres the flows in a river per second
high levels of runoff increase discharge of a river
hydrographs are graphs of discharge over time, they show how the volume of water flowing at a certain point in a river changes over a period of time
flood/storm hydrographs show river discharge around the time of a storm event, they only cover a relatively short time period.
-peak discharge: where river discharge is at its greatest
-lag time: time between peak rainfall and peak discharge
-rising limb: part of the graph up to peak discharge
-falling limb: after peak discharge
rapid runoff and not much storage = short lag time and high peak discharge = flashy hydrograph, steep and roughly symmetrical
34
factors affecting runoff variation
1) size of drainage basin: larger drainage basins catch more precipitation so they have a higher peak discharge than smaller basins. smaller basins generally have shorter lag times because precipitation has less distance to travel so it reaches the channel more quickly
2) shape of drainage basin: circular basins are more likely to have a flashy hydrograph the long narrow basins because all points on the watershed are roughly the same distance from the point of discharge measurement which means lots of water will reach the measuring point at the same time
3) ground steepness: water flows more quickly downhill in steep sided drainage basins, shortening lag time, this also means water has less time to infiltrate so runoff is higher
4) rock and soil type: impermeable rocks and soils dont store water or let water infiltrate, this increases surface runoff. peak discharge also increases as more water reaches the river in a shorter period.
35
changes in the water cycle
physical
storms and precipitation
intense storms generate more precipitation and greater peak discharges than light rain showers
larger input of water causes flows and stores to increase in size
some flows may not be able to occur rapidly enough for the size of input increasing runoff
36
changes in the water cycle
physical
seasonal changes and vegetation
e.g. summer drier than winter
during winter temps may drop below 0 causing water to freeze which can reduce the size of flows through drainage basins while the store of frozen water grows
when temperature increases again, flows are much larger as the ice melts
most plants show seasonal variation (dies back in winter), vegetation intercepts precipitation and slows its movement to river channel. interception is highest when there's lots of vegetation and deciduous trees have their leaves
the more vegetation there is in a drainage basin the more water is lost through transpiration and evapotranspiration before it reaches the river channel, reducing run off and peak discharge
37
changes in the water cycle
human activities
farming practices
farming practices affect infiltration:
- ploughing: breaks up surface so that more water can infiltrate, reducing run off
- crops increase infiltration and interception: compared to bare ground, reducing run off, evapotranspiration also increases which can increase rainfall
- livestock: compact soil, decreasing infiltration and increasing run off
- irrigation: can increase run off if water cant infitrate, groundwater or river levels can fall if water is extracted for irrigation
38
changes in the water cycle
human activities
land use changes
- deforestation: reduces the amount of water intercepted by vegetation, increasing the amount that reaches the surface. in forested areas dead plant material on the forest floor helps to hold the water, allowing it to infiltrate the soil rather than run off. when forest cover and dead material is removed, the amount of infiltration that can take place decreases
- construction of new buildings and roads creates an impermeable layer over the land preventing infiltration which massively increases runoff, resulting in water passing through the system much more rapidly and making flooding more likely
39
changes in the water cycle
human activities
water abstraction
more water is abstracted to meet demand in areas where population density is high, this reduces the amount of water in stores
during dry seasons even more water is abstracted from stores for consumption and irrigation so stores are depleted further
40
the carbon cycle
| lithosphere
99. 9% of the carbon on earth is stored in sedimentary rocks e.g. limestone
0. 004% is stored in fossil fuels e.g. coal and oil in the lithosphere
41
the carbon cycle
| hydrosphere
carbon dioxide is dissolved in rivers, lakes and oceans
the oceans are the second largest carbon store on earth, containing 0.04% of the earth's carbon, the majority of the carbon here is found deep in the ocean in the form of dissolved inorganic carbon
a small amount is found at the ocean surface where it is exchanged with the atmosphere
42
the carbon cycle
| atmosphere
carbon is stored as carbon dioxide and methane
| the atmosphere contains about 0.001% of the earth's carbon
43
the carbon cycle
| biosphere
carbon is stored in the tissues of living organisms, it is transferred to the soil when living organisms die and decay
the biosphere contains approximately 0.004% of the earth's total carbon
44
the carbon cycle
| cryosphere
less than 0.01% of earth's carbon
most of the carbon in the cryosphere is in the soil in areas of permafrost where decomposing plants and animals have frozen into the ground
45
carbon is transferred between different stores
the carbon cycle is the process by which carbon is stored and transferred
if sequestered carbon is released it is effectively an input
46
the carbon cycle
| stores
```
atmosphere
vegetation
soils
fossil fuels
earth's crust
oceans
sediments
```
47
the carbon cycle
| flows
```
volcanic eruptions
burning fossil fuels
combustion
respiration
ocean loss
sequestration
photosynthesis
decomposition
chemical rock weathering
ocean uptake
```
48
carbon stores changing over time due to carbon flows
| photosynthesis
transfers carbon stored in atmosphere to biomass
plants and phytoplankton use energy from the sun to change carbon dioxide and water into glucose and oxygen which enables plants to grow
carbon is passed through the food chain and released through respiration and decomposition
49
carbon stores changing over time due to carbon flows
| combustion
transfers carbon stored in living, dead or decomposed biomass to the atmosphere by burning
wildfires cause carbon flow
50
carbon stores changing over time due to carbon flows
| ocean uptake and loss
co2 is directly dissolved from the atmosphere into the ocean. it is also transferred to oceans when it is taken up by organisms that live in them
carbon is also transferred from the ocean to the atmosphere when carbon rich water from deep in the oceans rises to the surface and releases co2
51
carbon stores changing over time due to carbon flows
| sequestration
carbon from the atmosphere can be sequestered in sedimentary rocks or as fossil fuels
rocks and fossil fuels form over millions of years when dead animal and plant material in the ocean falls to the floor and is compacted
carbon in fossil fuels is sequestered until we burn them (combustion)
52
carbon stores changing over time due to carbon flows
| respiration
transfers carbon from living organisms to the atmosphere
| plants and animals break down glucose for energy, releasing carbon dioxide and methane in the process
53
carbon stores changing over time due to carbon flows
| decomposition
transfers carbon from dead biomass to the atmosphere and the soil
after death, bacteria and fungi break organisms down
cos2 and methane are released
some carbon is transferred to the soil in the form of humus
54
carbon stores changing over time due to carbon flows
| weathering
transfers carbon from the atmosphere to the hydrosphere and the biosphere
atmospheric carbon reacts with water vapour to form acid rain. when this acid rain falls onto rocks a chemical reaction occurs which dissolves the rocks
the molecules resulting from this reaction may be washed into the sea
here they react with co2 to form calcium carbonate which is used by sea creatures, e.g. to make shells
55
carbon flows happen over different time and spatial scales
fast carbon flows quickly transfer carbon between sources, minutes/hours/days, photosynthesis, respiration, combustion, and decomposition are examples of fast carbon flows
sequestration is a slow carbon flow
carbon flows taking place also depend on spatial scale,
plant scale: respiration and photosynthesis
ecosystem scale: combustion, decomposition
continental scale: all + sequestration
56
changes in the carbon cycle over time
natural variation
wildfires
wildfires rapidly transfer large quantities of carbon from biomass to the atmosphere
loss of vegetation decreases photosynthesis so less carbon is removed from the atmosphere
in long term fires can encourage growth of new plants which take in carbon from the atmosphere for photosynthesis.
depending on the amount and type of regrowth, fires can have a neutral effect on the amount of atmospheric carbon
57
changes in the carbon cycle over time
natural variation
volcanic activity
carbon stored within the earth in magma is released during volcanic eruption, the majority enters the atmosphere as co2
recent volcanic eruptions have released much less co2 than human activities however there is potential for a very large eruption to disrupt the carbon cycle significantly
58
changes in the carbon cycle over time
human impacts
hydrocarbon (fossil fuel) extraction and use
extracting and burning of fossil fuels releases co2 into the atmosphere
without human intervention the carbon would remain sequestered in the lithosphere for thousands/millions of years
59
changes in the carbon cycle over time
human impacts
deforestation
forests may be cleared for agriculture, logging or to make way for developments
clearance reduces the size of the carbon store and if the cleared forest is burned there is a rapid flow of carbon from the biosphere to the atmosphere
60
changes in the carbon cycle over time
human impacts
farming practices
agricultural activities release carbon into the atmosphere
animals release co2 and methane when they respire and digest food
ploughing can release co2 stored in soil
growing rice in rice paddies releases a lot of methane
as the world's population has risen, so has demand for food and as a result carbon emissions from farming practices have increased, mechanisation of farming has also increased co2 emissions
61
changes in the carbon cycle over time
human impacts
land use changes
from natural/agricultural to urban
vegetation is removed to make way for buildings which reduces carbon storage in the biosphere
concrete production releases lots of co2 and lots of concrete is used when urban areas expand
62
the carbon budget
the difference between the inputs of carbon into a subsystem and outputs from it
e.g. in the atmosphere, inputs of carbon come from volcanic eruptions, burning fossil fuels, respiration and ocean loss, and outputs occur through photosynthesis, sequestration, decomposition, chemical weathering and ocean uptake
balance on inputs and outputs determine whether it acts like a sink or a source
63
the impact of the carbon cycle on the
| atmosphere and climate
the carbon cycle affects the amount of gasses containing carbon in the atmosphere (greenhouse gases)
greenhouse gases trap the sun's energy, keeping some of the heat in and keeping the planet warm
as the concentration of greenhouse gases in the atmosphere increase )due to human activities) temperatures are expected to rise: global warming
changes in temperature across the global affect other aspects of climate, e.g. more intense storms are predicted
64
the impact of the carbon cycle on the
| land
the carbon cycle allows plants to grow, if there was no carbon in the atmosphere plants could not photosynthesise. if there was no decomposition, dead plants would remain where they fell and their nutrients would never be recycled
changes in the carbon cycle can reduce the amount of carbon stored in the land, e.g. warmer temperatures caused by global warming are causing permafrost to melt, this releases carbon previously stored in the permafrost into the atmosphere
an increase in global temperatures could also increase the frequency of wildfires
65
the impact of the carbon cycle on the
| oceans
co2 is dissolved directly into the ocean from the atmosphere
co2 in oceans is used by organisms such as phytoplankton and seaweed during photosynthesis and by other marine organisms to form calcium carbonate shells and skeletons
increased co2 in the atmosphere can increase the acidity of the oceans because oceans initially absorb more co2 which can have adverse affects on marine life
global warming can also affect oceans, e.g. organisms that are sensitive to temperature, e.g. phytoplankton may not be able to survive at higher temperatures so their numbers decrease. this means that less co2 is used by them for photosynthesis so less carbon is removed from the atmosphere
warmer water is also less able to absorb co2 so as temperatures rise the amount of co2 that could potentially dissolved in the sea decreases
66
the key role of carbon and water stores in supporting life on earth
all living things contain carbon and all living things need water to survive
plants form the base of most food chains, when photosynthesis occurs they use energy from sunlight to convert co2 and water into biomass that gets passed up the food chain, photosynthesis requires inputs of oth carbon and water
carbon exists as carbon dioxide and methane: greenhouse gases. they cause a natural greenhouse house effect that prevents some energy escaping into space and reflects it back to earth, this causes temperature on earth to be high than it would otherwise be. without the natural greenhouse effect the world would be uninhabitable and frozen
human activities are increasing the concentration of greenhouse gases in the atmosphere, most scientists agree this is causing an enhanced greenhouse effect where more greenhouse gases increase temperature further. this is thought to be causing global warming and other changes to global climate
67
interactions between carbon and water in the atmosphere
carbon combines with water in the atmosphere which allows chemical weathering which removes carbon from the atmosphere
water is needed for photosynthesis which removes carbon from the atmosphere
the amount of co2 in the atmosphere affects global temperatures which affect the amount of evaporation that can take place which in turn effects precipitation
68
feedbacks in the water cycle
| positive
temp rise, evaporation increases, amount of water vapour in atmosphere increases, greenhouse effect increases, repeat
increases global warming
69
feedbacks in the water cycle
| negative
temp rise, evap increases, amount of water vapour in atmosphere increases causing more clouds to form, increased cloud cover reflects more of sun's energy back into space, temps fall
70
feedbacks in the carbon cycle
| positive
temp rise, plant respiration rate increases, amount of co2 in atmosphere increases, greenhouse effect increases, repeat
increases global warming
71
feedbacks in the carbon cycle
| negative
co2 in atmosphere increases, extra co2 causes plants to increase in growth, plats remove and store more co2 from atmosphere, amount of co2 in atmosphere reduces
72
climate change implications for life on earth
1) pattern of precipitation predicted to change, wet areas get wetter and dry areas get drier which could cause water shortages in some areas which could lead to conflicts in the future
2) extreme weather events expected to get more frequent, less developed countries will be worst affected as they are less able to deal with the impacts
3) agricultural productivity will decrease in some areas which could lead to food shortages
4) sea levels expected to rise further which will flood coastal and low lying areas
5) geographical range of some species will change as climate changes, the arrival of new species in an area may damage the ecosystem and some species may become extinct
6) plankton numbers may decline if temperatures increase which will have a knock on effect on marine food chains
73
how humans have influenced/are influencing the carbon cycle
y extracting and burning fossil fuels
there is now 40% more co2 in the atmosphere than there was in 1750
the intergovernmental panel on climate change (ipcc) is an international organisation set up by the UN to share knowledge about climate change. the ipcc states that countries need to reduce the amount of co2 emitted by by human activities in order to prevent large temperature rise.
people are trying to mitigate the impacts of climate change by reducing transfers of carbon in the atmosphere
74
how humans are trying to influence the carbon cycle
| individual scale
use cars less and buy more fuel efficient cars
| make homes more energy efficient with double glazing, insulation and more efficient appliances
75
how humans are trying to influence the carbon cycle
| regional and national scale
governments can reduce reliance on fossil fuels for heating and powering homes by increasing the availability and reducing cost of renewable energy sources such as wind, tidal and solar
afforestation and restoring degraded forests can increase carbon uptake by the biosphere
planners can increase the sustainability of developments by improving public transport to reduce car use and creating more green spaces
governments can invest in carbon capture and storage. co2 emitted from burning fossil fuels is captured and stored underground
76
how humans are trying to influence the carbon cycle
| global scale
countries can work together to reduce emissions, e.g. kyoto protocol 1997 and the paris agreement 2015 and international treaties to control the total amount of greenhouse gases released. participating countries agree to keep their emissions within set limits
there are also international carbon trading schemes. countries and businesses are given a limit on the emissions they can produce, if they produce less they can sell extra credits, if they produce more they need to buy extra credits
