water and carbon cycles Flashcards
composition of global distribution of water
- 97% of water comes from oceans
- the 3% of freshwater comes from cryosphere, ground water, liquid freshwater and water vapour
water stores in litosphere
- surface water- rivers, lakes (Canada has 2 mil), wetlands (areas of marsh or peatland or water dominated by vegetation- Pentanal wetlands)
- ground water that collects in pores of rocks- aquifers (Africa and middle east)
- soil water- water held together with air, controls exchange of water and heat
- biological water- in plants and organisms taken up through roots and transported
water stores in hydrosphere
- 5 bodies of water and smaller seas covering 72% of Earth’s surface
- Pacific Ocean is the largest
- alkaline with average pH 8.14 but slowly becoming more acidic
water stores in atmosphere
- 12900 km ^3 of water vapour
- greenhouse has which absorbs, reflects and scatters solar radiation
- amount of water that air can hold depends on temperature, where cold air cannot hold as much
- clouds
water stores in cryosphere
- sea ice- water in ocean frozen below freezing (arctic ocean)
- permafrost- ground that remains frozen for at least two consecutive years (Alaska)
- ice sheets- glacial land ice more that 50,000km^2, constantly in motion (greenland and Antarctica)
- ice caps- glacial land ice less than 50,000km^2, mountainous areas, some shaped, flow outwards (Andes mountains)
- alpine glaciers- thick masses of ice found in deep valleys
explain 3 states of water and links between them
gas -> condensation -> water
water -> evaporation -> gas
water -> freezing -> solid
solid -> melting -> water
solid -> sublimation -> gas
gas -> deposition -> solid
define evaporation
when solar radiation hits the surface of water or land and causes liquid water to turn into gas
factors affecting rate of evaporation
- amount of solar energy
- humidity (closer to saturation point, slower rate of evaporation)
- temperature of the air ( warmer air holds more water)
define transpiration
plants lose water when it is transported up the roots and out the stomata in leaves
define condensation
air cools and dew point decrease so less water vapour can be held and turns into a liquid
when does condensation take place and what does the magnitude depend on
takes place when temperature falls to below dew point or when air rises so it cools and expands and loses energy (adiabatic cooling)
magnitude depends on amount of water vapour in the atmosphere and temperature
explain global atmospheric circulation
- pressure cells which leads to cloud formation and rainfall
- low pressure cells (ferrel cell) is where air rises and causes climatic instability
- high pressure cells (hadley and polar cell) is where at falls and leads to drier and more mild climates
- ITCZ is a zone which moves north and south between the seasons and causes unstable low pressure conditions
features of cloud formation
- not evenly distributed due to global atmospheric circulation
- vapour molecules require small particles to condense in (condensation nuclei) or surface that are cooler than the dew point temperature
- varies seasonally and by location
define frontal precipitation
warm air is less dense than cool air so is forced above and cools as rise
define orogtaphic precipitation
warm air meets mountains and is forced to rise over it and cools
define convective precipitation
sun heats up the ground and moisture on the ground evaporates and rises up in a column of warm air
effect of cryospheric processes on water magnitude
- accumulation- inputs to glacial system like snowfall
- ablation- output of glacial system due to melting
- sublimation- ice changing directly into water vapour
- in colder periods, inputs re greater than outputs and vice versa when warmer
define drainage basin
open and local hydrological cycles which surround the river where the rain falling on land flows into that river
define watershed
boundary of drainage basin and anything beyond goes into a different drainage basin
inputs in a drainage basin
precipitation- water that falls to the earth in any form like rain, snow, hail
storage in drainage basin
interception- precipitation lands on vegetation or other structures before reaching the soil
vegetation storage- water taken up by plants and contained with it
surface storage- water in puddles, ponds and lakes
soil storage- moisture in soil above water table
groundwater storage- water stores in saturated soil or rocks below the water table
channel storage- water held in a river or stream channel
flows in drainage basin
infiltration- water soaking into the soil influenced by soil type, structure and saturation
overland flow or runoff- water flowing over land when ground is saturated or surfaces are impermeable
through fall- water dripping one leaf to another
stem flow- water running down plant stem or tree trunk
throughflow- water morning through the soil, mainly along “pipes” caused by animal activity or cracks
percolation- water seeping through soil to the bedrock
groundwater flow- water flowing slowly below the water table through permeable rock
channel flow- water flowing in the river or stream itself
outputs in drainage basin
- evaporation
- transpiration
- river discharge
define water balance and the different types
different between the inputs and outputs in a drainage basin
positive- more precipitation so more water in the ground
negative- more runoff and evapotranspiration so ground stores are depleted
define soil moisture budget
change in the amount of water stores in soil throughout the year
define potential evapotranspiration
the amount of water that could be lost, where higher temperature cause more evapotranspiration
soil moisture equation
precipitation= total runoff + evapotranspiration +/- change in storage
define river regime
variability in its discharge throughout the course of the year in response to precipitation, temperature, evapotranspiration and drainage basin characteristics
define river discharge and its equation
amount of water that flows through a particular point in a river at a particular time, measured in cumecs- cubic metres per second
discharge= cross sectional area x velocity
what is a flood hydrograph
graph representing rainfall for a drainage basin of a river and its discharge following a rain event or storm
features of a flood hydrograph and definition
peak discharge- highest point on a graph, when river discharge is greatest
lag time- delay between peak rainfall and peak discharge when the rainwater is flowing into the river
rising limb- increase in river discharge as rainwater flows in and indicates how fast water is reaching the river
falling limb# decrease in river discharge as the river basin empties
define flashy and subdued hydrograph
flashy- short lag time and high peak discharge, so higher flood risk
subdued- long lag time and low peak discharge, so lower flood risk
human factors affecting discharge
- urbanisation- more impermeable surfaces like concrete which increases surface runoff
- pastoral farming- ground is trampled in so less interception and more surface runoff
- ploughing breaks up topsoil and allows for greater infiltration
- irrigation saturates the soil so more water cannot infiltrate
- deforestation- less interception by trees
- water abstraction- water taken out of store which reduces base flow so more water must reach the channel before it reaches capacity
physical factors affecting discharge
- intense storms and more rainfall create greater peak discharge and surface runoff
- antecedent rainfall (rainfall before the studied rainfall event)- ground is already saturated so the water has reached its field capacity
- geology- impermeable rock decreases percolation and increases through flow
- basin size and shape- small, steep sides and circular each river more quickly
- high drainage density with many tributaries increase speed of drainage
- temperature- low temperature has less evapotranspiration so greater peak discharge,low temperature also cause water to freeze
- precipitation type- snow or hail takes time to melt
- vegetation cover- forested areas intercept more areas
- seasonal variation- temperature and vegetation cover
how does deforestation affect the water cycle
- less evapotranspiration so less condensation and less precipitation
- less interception and higher surface runoff
- less stem flow and through fall so lag time is quicker
- over 10% of Amazon rainforest has already been converted to cattle pasture
- new vegetation has fewer leaves and shallower roots so it uses less water
how does soil drainage affect water cycle
- draining waterlogged soil to make it suitable for agriculture
- irrigating land for agriculture
- system of corrugated plastic tubing to drain water from soils when the water table is high
- tiles are made from short lengths of clay pipes
evaluation of soil drainage
+ build up of soil structure makes it easier to work
+ improved aeration makes favourable conditions for microorganisms to thrive which increases the rate that organic matter is broken down
+ heavy machinery can work on land without danger of compaction
- insertion of drains artificially increases speed of through flow
- dry topsoil is subject to wind erosion
- nitrate loss and lead to eutrophication
how does water abstraction affect water cycle
- groundwater pumped from ground
- intrusion of saltwater so countries resort to desalinisation plants
- irrigation causes ground water overexploitation
chalk of southern england water abstraction
- replenished during winter months
- 95% of flow is derived from underground reservoirs and can be abstracted
- abstraction has drastically reduced the flow in chalk streams and dried up certain parts of the river
physical factors of river exe
- 82.7km from north to south
- high drainage density as much of catchment is underlain by impermeable Devonian sandstones (84.4%)
- source is an upland peat bog area in open moorland
- maximum elevation of the river is 514m
rainfall and water balance of river exe
- 1097mm average rainfall
- high run off 65%
- impermeable bedrock reduced percolation and base flow
- if saturated or where drainage ditched have been dug, water can flow off the hills
land use of river exe
- urban areas in south like exeter, tiverton and cullompton
- remainder is rural with smaller villages and minor settlements
- agriculture like grazing
- 67% grassland
- 15% woodland
- 3% is moors and peat bog
human management along river exe
-wimbleball reservoir to create dam and supply water to Exeter and acts as a flood management by managing flow of river
- peatland restoration as drainage ditched increase the speed of water flow so exmoor mired project works to restore peat bogs by blocking drainage ditches to increase water content and return ground to boggy conditions
peatland restoration in river exe evaluation
+ more water storage in upper catchment
+ improved water quality- slower through flow so less sediment carried
+ more carbon storage- peat is a carbon store
+ improved opportunities for education, leisure and recreation
+ improved grazing and water supply for animals
features of long term carbon cycle
- carbon slowly and continuously being transported around our earth’s system
- 100-200 million years
- chemical weathering, volcanism, subduction, organic carbon burial and oxidation
- sequestration- carbon going into sedimentary rocks
features of short term carbon cycle
- a lot more carbon is moved around much faster
- time scale of days to thousands of years
- up-take of CO2 by plants on land and phytoplankton in oceans
- transfer of carbon to soils by dropping of leaves, root growth and respiration
- decomposition of plants
difference between organic and inorganic carbon
organic is living (plants) and inorganic is non-living (rocks)
difference between organic and inorganic carbon
organic is living (plants) and inorganic is non-living (rocks)
compounds of carbon
- carbon dioxide
- methane
- fossil fuels
- calcium carbonate
- graphite
origins of carbon
- earths interior like mantle at constructive and destructive plate boundaries
- biomass
define carbon sink
absorbs more carbon that releases, like tropical rainforest
define carbon source
releases more carbon that it absorbs
carbon stores in atmosphere
- CO2 gas (0.04%)
- methane
carbon stores in lithosphere
-marine sediments
- soil organic material
- peat
- fossil fuel deposits (0.004%)
- sedimentary rock like limestone and chalk (99.9%)
carbon stores in cryosphere
- soil like permafrost (<0.01%)
carbon stores in biosphere
- animals
- plants (19%)
- organic matter in soils, plant litter and soil humus
- 20% tropical rainforest
- 26% boreal forest
- 10% temperate grassland
- 9% agriculture
carbon stores in hydrosphere
- calcium carbonate in shells
- living and dissolved organic matter
- surface layer via photosynthesis from plankton
- intermediate and deep layer of ocean- marine food chains and then decomposes
define carbon flux
amount of carbon exchanged between Earths carbon pools
weathering in carbon cycle
- breakdown or decay of rock in situ
- carbon stored within is returned to the carbon cycle
- CO2 is absorbed by rainwater to form carbonic acid, which makes rocks slowly dissolve like limestone
- this is transported by the water cycle to the oceans and the carbon can build the shells of marine organisms
burial and compaction in carbon cycle
- organic matter dies and is buried by sediment and becomes compacted
- over millions of years, this can form hydrocarbons
photosynthesis in carbon cycle
- plants use light energy from the sun to produce glucose
- plants absolve light from chlorophyll in chloroplasts
- absorbed light energy converts CO2 in the air and water from the soil into glucose
- releases oxygen into the air
- some glucose is used in respiration
- carbon dioxide + water -> glucose + oxygen
respiration in carbon cycle
- use the glucose they stores as an energy store to carry out life functions
- consumers such as animals and bacteria then eat them and get their energy
- glucose + oxygen -> carbon dioxide + water
decomposition in carbon cycle
- when organisms die they are consumed by decomposers cub as bacteria, fungi and earthworms
- carbon from their bodies is returned to atmosphere
- some organic material passes into the soil where it may be stored for hundreds of years
combustion in carbon cycle
- organic material is burned in the presence of oxygen and is converted into energy, carbon dioxide and water
- organic material can be vegetation or fossil fuels
- carbon dioxide released into atmosphere
ocean uptake and loss in carbon cycle
- carbon dioxide is directly dissolved from the atmosphere into the ocean (diffusion) and can be taken up by organisms like phytoplankton
- carbon can be transferred from the ocean to the atmosphere when carbon rich water from deep in the ocean rises (vertical deep mixing)
-oceanic carbon pump- vertical circulation between oceans and atmosphere, biological or physical
natural sequestration in carbon cycle
- carbon can be sequestration sedimentary rocks or as fossil fuels
- carbon in fossil fuels is sequestrated until we burn them
wildfires in carbon cycle
- carbon dioxide releases when forests are burnt
- nutrients can be returned and new saplings grow- negative feedback loop
- larger and more frequent fires can threaten natural balance
volcanic activity in carbon cycle
- carbon stores in magma is realised during volcanic eruptions
- can release gases through soil, volcanic vent and fumaroles
- account for small amount of carbon movement- produce less than 1% of carbon dioxide released currently by human activity
natural fast carbon flows
photosynthesis, respiration, combustion and decomposition
natural slow carbon flows
sequestration
plant scale carbon flows
photosynthesis and respiration
ecosystem scale carbon flows
combustion and decomposition
continental scale carbon flows
all carbon flowa
farming practices in carbon cycle
- when soil is ploughed, soil layer invert with each other, allowing air to mix, which increases soil microbial activity and more soil matter is decomposed
- emissions from farm tractors increase carbon dioxide
- livestock like cattle ruminate and releases methane- cattle in US releases 5.5 million tonnes a year
- agriculture and forestry cause 1/4 of all human greenhouse gas emissions
- rice paddies- 10% of all agricultural carbon emissions
- rice yields in Asia and North America increases by 25%
- soil erosion where areas are over cultivated and stripped of its nutrients and minerals
cement manufacture in carbon cycle
- calcium carbonate is heated to produce cement and releases carbon dioxide
- 50% of global anthropogenic emissions comes from cement production
- amount of carbon dioxide emitted is more than 900kg of carbon dioxide for every 1000kg of cement
- carbon dioxide is also produced by burning fossil fuels that provide heat for cement manufatcure
deforestation in carbon cycle
- 13 million hectares of forest are cut down and change to other land uses every year
- forest soils are moist but without shade from trees they will dry iut
urban growth in carbon cycle
- over half of the worlds population lives in urbana eras and expected to reach 60% by 2030
- carbon dioxide emissions from energy consumption and domestic use like transport
- concentrated around most polluting cities like Seoul, New York- 10% of all energy related carbon emissions
fossil fuel combustion in carbon cycle
- 90% of all human caused carbon comes from combustion of fossil fuels
- vegetation and the oceans help to reabsorb 50% of this
geological sequestration in carbon cycle
- carbon dioxide captured at its source and injected in liquid for to stores underground, like depleted oil and gas reservoirs
- dissolved in ocean within weeks or months
- much more than terrestrial
terrestrial sequestration in carbon cycle
- plants to capture carbon dioxide and stored in stems, roots and soil
- benefit enrichment of plant ecosystems
- can be damaging in forest fires, where carbon is released
define carbon budget
list of all the carbon pools with an estimate of their size and a summary of the differences between the inputs and outputs
impact of changing carbon cycle on land
- changes in carbon cycle can reduce carbon stored in land like permafrost melting
- increase frequency of wildfires
- carbon fertilisation- plants can grow more as more atmospheric carbon dioxide converts to plant matter
impact of changing carbon cycle on oceans
- increase carbon dioxide can increase acidity of oceans as they absorb more carbon dioxide
- since 1750, pH had dropped by 0.1
- with global warming, organisms that are sensitive to temperature like phytoplankton may not be able to survive
- increasing in acidity kills coral reefs
- warmer water absorbs less co2
- melting of land ice makes the oceans absorb more solar radiation, which increase temperatures more- positive feedback
- sea level rise from increasing melting of ice and precipitation
impact of carbon cycle on atmosphere and climate
- added carbon contributes to greenhouse gas emissions and the enhanced greenhouse effect
- links to climate change, and more intense storms and weather
- as much as 20% additional carbon dioxide will remain in atmosphere
- radiative forcing where an increase in carbon budget can enhance greenhouse effect
- low albedos can also enhance greenhouse effect
what is the MOC or thermohaline circulation
system of ocean currents that connects all the oceans and is driven by temperature and salinity
- cold, salty water is dense and sinks
- increased water from melting of Greenland reduced salinity of oceans which leads to unknown impacts
define radiative forcing
difference between incoming solar energy absorbed by the earth and energy radiated back to space
impact of carbon and water cycle on tropical rainforests
- plants and trees act as carbon sinks
- deforestation releases carbon
- local precipitation levels and patterns change
impact of carbon and water cycle on regional climate (weathering)
- sulphur dioxide can lead to acid rain
- carbon in carbonate rocks can be dissolved and carried away into water
impact of carbon and water cycle on atmosphere
- increasing concentrations of carbon leads to global warming which can increase precipitation and exacerbate aridity
- volcanic eruptions release carbon dioxide and water vapour
- photosynthesis requires both precipitation and carbon dioxide
- decomposition release co2 and needs to be in the presence of water
- acid rain and ocean acidification
impact of water and carbon cycle on oceans
- warmer oceans cause more plankton growth and through the chemical production can lead to cloud production
- warmer oceans store less co2 so higher temperatures could lessen the effects of oceans as carbon sinks
what would be the normal conditions of trade winds (el nino)
trade winds blow towards the warm water in the west and keeps it warm by australia, which leads to low air pressure as it rises
what would be the conditions during el niño
winds weaken and mass of warm water migrates back to South America and Australia experiences high acre pressure
what would the conditions be during la niña
- conditions return back to normal but very extreme so there is extreme wet in the west and extreme dry int he east
positive feedbacks in water and carbon cycle
- increase in co2 leads to an increase in the temperatures of the atmosphere and warm air holds more water vapour, which helps the earth to hold more heat energy
- warm temperatures melt ice which causes a lower albedo as less sunlight is reflected and temperatures increase
- wildfires from climate change release co2, which contributes more to climate change
- high temperature thaw permafrost and release the carbon held
negative feedbacks in water and carbon cycle
- increased photosynthesis from rising temperatures allows vegetation to grow in new areas to absorb excess co2 released
- higher temperatures and amounts of co2 can cause greater fertilisation in plants so they absorb more co2
define mitigation of climate change
anthropogenic intervention to reduce the source or enhance the sinks of greenhouse gases
scales of mitigating against climate change
global scale-global institutions like UN
national scale- individual governments
local scale- local initiatives
individual scale- decisions and consumer choices
carbon capture as a method of mitigating against climate change
- capturing, transporting and storing underground in depleted oil or gas fields
- carbon capture and storage captures carbon dioxide from power stations and transport to a site to be stored
- carbon is then compressed and transported by pipeline to an injection well and injected as a liquid into reservoirs
- Boundary Dam in Canada- cuts co2 by 90%
geo sequestration as a method of mitigating against climate change
co2 stored in deep geological formations like volcanic basalt in Iceland
global scale strategies against climate change
- paris climate agreement aimed to limit the increase of global temperatures to 2C above pre-industrial levels, and developed countries were to commit $100 billion to support developing countries
- kyoto 1997- gave each country a quota on how much carbon they can emit, US and Australia did not sign up
- international carbon trading schemes where countries are given a limit on the emissions they can produce via credits
national scale strategies against climate change
- net zero by 2050
- carbon capture and storage
- electrification of transport
- eradication of coal from our energy mix
local scale strategies against climate change
- increase sustainability of area- electric buses
individual scale strategies against climate change
- recycling
- reducing food miles
- using energy more efficiently- smart meter, renewable energy
changing rural land use to mitigate against climate change
- farming and deforestation
- carbon farming- one type of crop is replaced by another with a greater productivity and absorbs more carbon
- consumers encouraged to buy wood from FSC- timber that has been grown sustainably
- countries and organisations can offset their carbon emissions through payments, which goes towards protecting forests
changing grasslands to mitigate against climate change
- offer a global greenhouse gas mitigation potential of 810 million tonnes of co2
- avoidance if overstocking grazing animals
- adding manures and fertilisers that have a direct impact on soil organic carbon
- revegetation
- irrigation and water management
changing crop lands mitigating against climate change
- reduced or no tillage
- no ploughing
- use if animal manure
- mulching- thick layer of organic material added
- rotation of cash crops
- use improved crop varieties
changing forests and tree crops mitigating against climate change
-forests store large amounts of co2
- protection- preserve current firests
- reforesting
improving aviation practices mitigating against climate change
- 2019- 4.5 billion air passengers emitting 915 million tonnes of co2
- flight management- 100% occupancy of seats and cruising at lower speeds
- movement management- avoid circling
- fuel efficient routes
- increasing engine efficiency- use of biofuels, increasing aerodynamics, reducing weight of aircraft, CC with engines
main characteristics of amazon rainforest
- worlds largest tropical rainforest
- covers 40% of south american landmass- brazil, venezuela, columbia
- 300 billion trees and 15000 store 1/5 of all the carbon in the planets biomass
- hot and wet climate with dense vegetation
- home to 1 million plant species and 500 species of mammals
amazon rainforest and water cycle
- 2,300mm precipitation annually
- a lot of vegetation from hot climate means high evaporation rates
- dense canopy so high interception
- animals adapted to high humidity and frequent rainfall
- 30% of rainfall reach the sea
- high surface runoff
amazon rainforest and carbon cycle
- carbon sink- store 100 billion tonnes of carbon
- increasing carbon dioxide has led to increased productivity as vegetation can photosynthesise
- trees are growing quicker but also dying younger
vegetation changes in amazon rainforest
- WWF estimates 20% of Amazon rainforest has been lost and will rise to 27% by 2030
- can affect species sustainability
- droughts
- 2009 study concluded 2C rise would see 20-40% of Amazon die off within 100 years
soil changes amazon rainforest
- amazon soils contain 4-9kg of carbon in upper 50 cm of soil
- when burned, 30-60% is lost
- heavy rainfall after deforestation rapidly washes away topsoil
- deforestation means less leave litter so humus is not formed
river changes in amazon rainforest
- reduction in river discharge
- increased silt in rivers
- flash flooding
- destroy freshwater ecosystems
mitigation in amazon rainforest
- TARAPOTO process- forest policy makers from 8 member countries identified 12 criteria to help manage forest sustainability
- amazon cooperation treaty organisation to promote harmonious development
- create national parks and forest reserves- the Para rainforest reserve (15 million hectares)
- reforestation
- enrichment of degraded forests
- selective logging
