water and carbon cycle Flashcards
define energy
the ability to do work
define flow/transfer
a form of linkage between one store and another that involves movement of energy/mass
define input
the addition of matter/energy into a system
define output
the result of the processes within a system
define store/component
a part of a system where energy/mass is stored or transformed
define a system
a set of interrelated components working together towards some kind of process
define elements
things that make up a system
define attributes
the perceived characteristics of an element
define relationships
descriptions of how the various elements work together to carry out some kindof process
what are the simplifications of the relationships between components in the earth called
models
give an example of a model
the water cycle
what are the characteristic of a system
they have a structure that lies within a boundary
they are generalisations of reality
function by having inputs and outputs of material
involve the flow of material between components
what can systems be classified as
isolated
closed
open
define an isolated system
these have no interactions with anything outside of the system boundary
these are rare in nature
there is no input or output of energy or matter
define a closed system
these have transfers of energy both into and beyond the system boundary but not transfer of matter
define a closed system
these have transfers of energy both into and beyond the system boundary but not transfer of matter
define a closed systems
these are where matter and energy can be transferred in and out of the system boundary
define dynamic equilibrium
when there is a balance between the inputs and outputs of a system
natural state of balance
define positive feedback
when the effects of an action are amplified by knock-on secondary effects
define negative feedback
when the effects of an action are nullified by its knock-on secondary effects
how much of total water is fresh water?
2.5% and 99% of it is in the cryosphere
Name the 3 types of rainfall
frontal
convectional
relief
describe relief rainfall
Moist air is forced to rise due to hills and mountains causing it to cool and condense and rain.
Describe frontal rainfall
warm and cold air masses meet and the lighter warm air is forced to rise over the colder denser air leading it to cool and condense forming rain
Describe convectional rainfall
Hot air heated by the sun rises and as it rises it begins to cool and condense and heavy dark storm clouds tend to form (cumulo nimbus)
define drainage basin
an area of land drained by a river and its tributaries
Define watershed
An imaginary line separating drainage basins and is usually a ridge of high land
define stemflow
direction of precipitation down a plants leaves and branches and stems
How do you calculate the water budget?
precipitation =
runoff + evaporation +/- change in storage
What is base flow in a flood hydrograph?
normal day to day discharge of the river as a consequence of groundwater seeping into the river
What is overland flow?
All water running on the surface
What is the falling / receding limb
how long it takes for river discharge to reduce
What 7 factors can affect the shape of a flood hydrograph?
drainage
rock type land use relief temperature antecedent conditions rainfall basin shape/size/density
How can drainage density affect discharge?
low density (less tributaries) = longer lag time high = shorter lag time
Define spatially
over different areas e.g. rural and urban
Define temporally
Over time e.g. seasons, temperature
Explain the effects of deforestation on the water cycle.
There is less interception by trees so surface run off increases and soil water storage and transpiration decreases
Explain the effect of storm events on the water cycle
Large and quick amounts of rainfall saturate the ground to its field capacity and increases run off. Less water infiltrating in the soil and percolating into rock reduces replenishment of water stores
Urbanisation also causes more impermeable surfaces
Explain the effect of seasonal changes on the water cycle
Spring - there is more interception due to more vegetation.
summer- less rain and can make the ground harder and more impermeable
Autumn - more rainfall and less interception
Winter- hard frozen ground which may be impermeable, snow discourages run off and takes a long time to melt slowing down processes in the cycle
Define irrigation
Movement of water through human intervention
Explain the effects of pastoral farming
Livestock can trample the ground making it more compact reducing infiltration.
Explain the effects of arable farming on the water cycle
Ploughing increases infiltration however drainage ditches increase surface run off and stream flow
Define field capacity
The maximum possible level of water in the soil
What else is the water budget dependant on?
Type, depth and permeability of soil and bedrock
Describe the soil water budget in autumn.
There is a greater input from precipitation than there is an output in evapotranspiration as deciduous trees loose their leaves and less photosynthesis occurs - water surplus
describe the soil water budget in winter
Potential evapotranspiration reaches a minimum and precipitation continues to refill water stores
Describe the soil water budget in summer
Utilisation of soil water in evapotranspiration peaks and rainfall is at a minimum so output is grater than input and soil water stores are depleting
Describe the soil water budget in spring
Potential evapotranspiration increases but there is still a water surplus
Define abstraction
Taking water from rivers and lakes etc
define salinisation
when too much water is removed causing salt to get into groundwater stores
Define leaching
too much water leads to chemicals in soil to leach out of soil
Define eutrophication
When chemicals get into water stores / flows and can poison aquatic life
Define unconfined aquifer
susceptible to contamination and is closer to the surface
Define confined aquifer
less prone to contamination due to rock seal
What are the consequences of over-abstraction
Impacts of flows of water
subsidence
saltwater intrusion
impacts on stores of water
How does over abstraction impact flows of water
Streams either gain water from inflow of ground water or lose water by outflow to groundwater
Aquifers can impact quantity and flow of water in a river
how can over abstraction lead to subsidence
Loss of water can lead to collapse of rock
How can over abstraction lead to salt water intrusion
When water is pumped from an aquifer near or that contains saline groundwater it can cause the salt water / fresh water boundary to move and the salt water can contaminate fresh water supplies
How can over abstraction impact stores of water
Lowering of lake levels by pumping can affect the ecosystems supported by the lake and have negative effects on shoreline structures
What is the difference between a flashy and subdued hydrograph
flashy - short lag time and steep rising and falling limbs with a higher flood risk and high peak discharge
subdued - long lag time with gradual rising and falling limbs with low peak discharge and a lower flood risk
What are some natural factors that affect flood hydrographs
Rainfall intensity drainage density small basin shape of basin precipitation vegetation
What are some human factors that can affect the shape of a flood hydrograph
urbanisation
land use
deforestation
What is an aquifer
It is a long term water store
Describe the pattern of water storage
oceans have 97% of water
2.5% Of all water is fresh water and 69% is stored in glaciers
What does low pressure and high pressure cause?
low pressure - rising warm air - heavy rainfall
high pressure - descending cooler air - arid / unstable
define weathering
Breaking down or dissolving rocks and minerals on Earths surface
What is physical weathering
Freeze thaw - water enters cracks, freezes and expands widening cracks
Exfoliation - cracks parallel to the Earths surface due to erosion
Define biological weathering
Roots of plants and animals burrow down weakening the structure of the rock and break it down
Define chemical weathering
Rocks such as limestone and chalk dissolve in acid rain
What are the 7 transfers of carbon in the carbon cycle
Photosynthesis decomposition combustion sequestration transfer of carbon respiration weathering and erosion diffusion - oceans can absorb co2
What is the size and distribution of carbon in the lithosphere
marine and sedimentary rock (100 000b tonnes) the largest store of carbon and is a long-term store of carbon as rocks take millions of years to form.
Fossil fuel (4000b tonnes) important long term stores of carbon which have been exploited since the industrial revolution
Describe the size and distribution of carbon in the hydrosphere
(3800b tonnes) The oceans are a very important store of carbon as they absorb CO2 and river water discharges carbon carried in solution
Describe the size and distribution of carbon in the biosphere
Soil and organic matter (1500b tonnes) carbon can remain in the soil for hundreds of years. It also contains rotting matter
Terrestrial plants (560b tonnes) can store carbon for hundreds of years and transfer it to soil
Describe the size and distribution of carbon in the atmosphere
(750b tonnes) Carbon is held in the form of CO2
What processes can cause carbon to move quickly
Combustion, respiration and carbon sequestration because they release carbon quickly and happens in a short amount of time
What processes move carbon slowly
Decomposition as carbon is released over a longer period of time for example fossil fuel creation which takes place over millions of years
What biome stores the least amount of carbon and why
The tundra because of its freezing conditions so decomposition takes longer and there is also smaller biodiversity
How does combustion of biomass alter levels of carbon in the atmosphere
Plant carbon is released into the atmosphere in the event of a wildfire
dense areas of carbon storing plants are eliminated that would take CO2 put of the atmosphere
Lost plants are replaced with new plants and young plants don’t store as much carbon
Exposed soil releases co2 from the decaying matter
What are some natural causes of carbon variation in the planet
volcanic eruptions
wildfires
How significant are natural causes of carbon variation to our planet
volcanic eruptions contribute a relatively low amount CO2 to the atmosphere and wildfires are estimated to make up around 5-10% of annual carbon emissions whereas in the US household consumption makes up 20% of their emissions
What are some natural causes of variation in the carbon cycle
wildfire
Volcanic activity
What human impacts can cause changes to the carbon cycle
fossil fuel use - co2 levels in the atmosphere have increased by 40% since the industrial revolution
Deforestation
Agriculture
What is the carbon budget
balance between inputs and outputs in a store
The balance of exchanges
How has the carbon budget changed since the industrial revolution?
The dynamic equilibrium is being lost so there are more emissions than storage
Amount of CO2 in the atmosphere has increased by 40% since the industrial revolution
What are the impacts of the carbon cycle on the land
It is a source of energy - wood
Increased CO2 can lead to increased growing seasons and decay
Carbon cycle is responsible for the formation and development of soil which is essential for plant growth and nutrients
What are the impacts of the carbon cycle on the oceans
30% of released co2 is absorbed into the oceans creating carbonic acid and ocean pH has dropped by 0.1 since 1975
Melting sea ice affects primary producers and food chains and animals can no longer travel on ice
can lead to more phytoplankton
Oceans are expected to rise by 0.8-2mm by 2100
poses a threat to coral reefs which provides food and livelihood security for millions a fall in marine biology can threaten food security
phytoplankton are very sensitive to salinity and temperature and if they cant adapt their numbers may diminish
What is the ocean conveyer belt?
It is very important to our climate as it is a combination of currents that results in 4/5 global oceans exchanging water with each other
What is thermohaline circulation
The movement of water dependant on temperature and salinity
How does melting polar ice caps affect thermohaline circulation
There would be a reduction in salinity leading to a reduced density so the North Atlantic current would not be heavy enough to sink
Define climate mitigation
actions put in place to reduce or stop climate change
What is alternative energy production?
They are alternative sources of energy often referred to as renewable as they can be quickly replenished and can be used indefinitely e.g. solar, wind, HEP
How do alternative energy resources help to reduce co2
they don’t emit co2 as a biproduct
for example solar power uses pv cells and convert uv rays into electricity
A 100% solar strategy by 2050 would reduce ghg emissions by 119%
What are some possible problems with alternative energy
If there is no sun there will be no power with solar power
Wind takes up space and is noisy
HEP is expensive
What is carbon capture
Ways to capture co2 from power plants and factories and safely store it in the ground
How does carbon capture work to reduce co2 in the atmosphere
it allows time to develop renewable energy and these mechanisms have already captured 40 million tonnes of co2
What are some possible problems with carbon capture
it may distract governments from the need to convert to renewable energy
carbon leaching may occur
Amount of money going into developing carbon capture may double the price of electricity and waste money which could be invested in green energy
What is afforestation?
Plant more trees in order to absorb more co2
How does afforestation help to reduce co2 in the atmosphere?
Trees photosynthesis and convert co2 into oxygen
Younger trees also absorb co2 quicker
What are some problems associated with afforestation?
We would need lots of trees for forests to become a net carbon sink which isn’t very realistic
What are some international agreements on climate change mitigation?
COP21 - an agreement made by 195 nations on climate change
Paris 2015 - agreement to cut GHG emissions and to keep temperature rise to a maximum of 2C
Kyoto - commits state parties to reducing GHG
by getting lots of countries to sign we can make a global difference
What are some possible problems wit international agreements regarding climate mitigation?
it is unfair to ask other countries such as China to reduce their emissions as it will mean their economy will suffer and historically the UK and USA had emitted large amounts of CO2 during their industrial revolutions
USA has backed out of the paris agreement
how does soil drainage affect the water cycle
subsurface drainage removes excess water from the soil profile and this lowers the water table to the depth of the tiles over the course of several days
what are the advantages of soil drainage
increases productivity of a field
improved aeration increases rate at which organic matter is broken down into humus
heavy machinery can work on land without danger of compaction
what are the disadvantages of soil drainage
increases speed of throughflow
increased likelihood of flood and range of flow in rivers
dry topsoil can be subject to wind erosion
can lead to eutrophication
what’s a disadvantage of water abstraction
sinking water tables which can lead to saline intrusion degrading the groundwater
can make rivers less reliable
what is the main cause of groundwater over exploitation
irrigation
example
Greek Argolid plain it is common to find boreholes 400m deep contaminated by seawater intrusion
what can reduction in abstraction lead to
groundwater levels recovering by as much as 3m/yr in places
What is a carbon pump and vertical deep mixing
where carbon dioxide is transported from the ocean surface to the ocean depths by sinking cold water in the high latitudes
if brought to the surface the cold water will warm up and release some of its carbon dioxide to the atmosphere
what are the impacts of ocean acidification
carbonic acid reacts with carbonate ions to form bicarbonate
lack of carbonate ions means animals need to expend more energy to make their shells so they become thinner
significant reef loss leads to consequent fall in marine biodiversity threatening the survival of coastal communities and reduce capacity of coasts to be able to buffer impact of sea level rise
what does ocean warming lead to
limit ability of ocean to take carbon from the atmosphere through biological carbon pump - phytoplankton
kills symbiotic algae
describe melting sea ice
arctic retreat of 12.8% per decade
what is radiative forcing
balance between incoming and outgoing energy and if it is anything but zero there will be warming
