Water and Carbon Cycle Flashcards
Main characteristics of tropic rainforests
between two tropics
annual rainfall 2000+ mm; 27.C (ideal for plant growth and very efficient circulation of water)
home to 200mil + 1/2 worlds species
emit 28% worlds oxygen
Tropical Rainforest water cycle
precipitation very high bc high humidity & unstable weather conditions associated with tropics
forest intercepts 75% - some drips to ground from leaves/stemflow - 25% evaporates - 75% 1/2 used by plants and returned to atmosphere by evapotranspiration 1/2 infiltrates
desertification
turning marginal land into desert by destroying its biological potential
gauging station
site used to monitor and collect data about streams, river and other land-based bodies of water
groundwater flow
transfer of water very slowly through rocks
lithosere
vegetation succession that originates on bare rocky surface
lithosphere
outermost solid layer of Earth (100km thick) comprising the crust and upper mantle
percolation
Vertical movement of water down the soil into the underlying rock
psammosere
vegetation succession that originates in a coastal sand dune area
recharge
additional water flowing into rock
respiration
chemical processes that happens in all cells, which converts glucose into energy
river regime
pattern of discharge over the course of a year
sere
complete vegetation succession
sublimation
transfer from a solid state (ice) to gaseous state (water vapour) and vice versa
vegetation succession
sequence of changes that take place as plant life colonises bare rock, sand, water or salty areas
global hydrological cycle
continuous movement of water on, above and below earth
describe hydrosphere (saline water in oceans)
96.5% global water
supplies 90% of evaporated water which goes back into atmosphere
southern hem more water than north because it has more land
long-term: big fluctuations e.g. 18,000 years ago, SL up to 120m lower than present - 1/3 of world land area covered in glaciers/ice sheets
short-term: relatively small eustatic change to SL, but general trend SL rising
during interglacial, water added to store from cryosphere, means more water is available for hydrological cycle, speeds cycle up vice versa for ice age
describe hydrosphere (fresh surface water)
1.2% global freshwater
lakes & rivers not evenly distributed e.g. Great Lakes of North America, Caspian Sea
Long & short-term: level varies with climate (glacial / interglacial and varies seasonally)
describe cryosphere (ice)
68.7% global freshwater
covers 10% earth’s surface
95% in Antarctica & Greenland
ice help in many forms: ice caps/sheets (covers 20,000 square miles of land e.g. Antarctica, Iceland, Greenland, glaciers (covers less than 20,000 square miles), ice shelves, sea ice (can freeze & thaw yearly e.g. Arctic)
long-term: variations with glacial + interglacial periods
short-term: seasonal variations, accumulation (build up ice mass), ablation (loss ice mass), calving (in winter glaciers accumulate less and summer ablate more)
describe lithosphere (rock and soil)
groundwater 30.1% global freshwater
soil moisture storage varies e.g. sand porous + permeable so transfers water through it storing little - clay porous but impermeable so stores
groundwater aquifers: rock that store water e.g. Chalk, sandstone create vast reservoirs
long-term: depend on location (historical plate movement) + changes in climate
short-term: depends on season + climate change
describe atmosphere
0.001% global water
90% water input by evaporation + 10% transpiration
spatially amount of water in atmosphere determined by tri-cellular model
long-term: varies with availability of water + temperature (ice ages)
short-term: seasonal variations, global warming, extreme events
describe biosphere
0.26% surface water
distribution over space and time varies by biome + season
Drip/ stem flow
Water drips off leaves and branches until it reaches ground
Transpiration
Plants loose water back to atmosphere through stomata on leaves
Surface storage
Water stored in depressions on the surface e.g. puddles, ponds, lakes
Throughflow
Lateral movement of soil water downslope
Soil moisture storage
Water stored in pore spaces in the soil
Groundwater storage
Water held in pore spaces in the rock
Groundwater flow
Very slow lateral movement of water through rock
Water table
Upper layer of saturated ground
Examples of drainage basins
Mississipi largest US drainage basin
2.981 million km²
Amazon basis largest in world: 7 million km²
Equation for water balance
P = Q + E +/- S
P (precipitation)
Q (discharge runoff (amount of water flowing into channel))
E (evapotranspiration)
S (storage)
Helps hydrologists plan fr future water supply and flood control by understanding unique hydrological characteristics of individual water basin
Factors causing variations in stores of the drainage basin:
Deforestation (removal of trees reduces interception + infiltration - overland flow increases)
Storms (intense rainfall increases about of rain reaching ground + increases magnitude of stores)
Seasonal changes (winer snowfall + frozen ground interrupt water transfers + affect magnitude of stores)
Urbanisation (impermeable surfaces reduce infiltration - trees cut - water flow quickly through pipes to nearby river channels)
Farming (ditches drain land + encourage water flow quickly to rivers- irrigation increases amount of water on ground)
Variations in runoff
Lack of trees, 90% runoff, 10% evapotranspiration + storage, saturated soil, impermeable rock
Trees, 50% evapotransiration + storage, lake (storage), 50% runoff, dry soil, permeable rock
Time of year affect rates of evapotranspiration + veg growth (interception)
Type + intensity of precipitation
The river Wye, Wales
Upper basin: steep slopes, acidic soils, grassland - area originally forested but cleared for pasture + grazing reducing interception + increase potential for overland flow - ditches dug to drain land to make it more productive this increases speed of water transfer making prone to floods
Rocks upper basin impermeable must ones, shales + grits making groundwater flow limited: soils quickly saturated + unable to absorb excess water encouraging overland flow increasing risk of flooding downstream
Value for river discharge in cumecs
Discharge (m³ per second) = cross-sectiona area (m²) x. Velocity (metres per second)
Characteristics of flashy hydrograph
Impermeable rocks encourage rapid overland flow (clay)
Saturated antecedent conditions
Steep slopes raid water transfer
High drainage density speed up water transfer
Small drainage basin - rapid transfer
Drainage basin- steep sides and small
Urbanisation - tarmac
Heavy rain may exceed infiltration capacity of veg + rapid overland flow
Deforested
Yes agriculture increase runoff rate up and down ploughing
Characteristics of a subdued hydrograph
Permeable rocks encourage slow transfer by ground-water flow (sand)
Unsaturated antecedent conditions
Gentle slopes slow water transfer
Low drainage density
Large drainage basin
Gentle sides flat
Interception
Light rain transfer slowly
Forested
No agriculture contour ploughing
Purpose of flood hydrograph
Track progress of storm in drainage basin
By looking at previous flood hydrographs it’s possible to access likelihood of flood or dangerous events like high flow rates
To prepare, raise flood barriers or declare rivers unsafe to users
consequences of over-abstraction
ground less stable - causing subsiding & cracking cause damaged infrastructure
wells & boreholes cause health hazards - substances mix with fresh water
over-abstraction: saltwater intrusion
fresh groundwater system come into contact with oceans (saltwater) -> make water unpotable + freshwater less dense so flows on top underlying saline groundwater
when water pumped from aquifer near saltwater / freshwater boundary will move in response to pumping so contaminate water supply
over-abstraction: impacts on stores of water
lowering lake levels by groundwater pumping affect ecosystems supports by lake, diminish lakefront aesthetics + -tive effects on shoreline structures
over-abstraction: impacts on flows of water
over-abstraction from aquifers impact quantity & flow of water in river
long-term reductions in streamflow affect vegetation that serves roles in maintaining wildlife habitat + enhancing quality of water supply
pumping-induced changes in flow direction affect temperature, oxygen levels, nutrient concentrations
over-abstraction: subsidence
damage structures + create problems in operation of facilities for drainage, flood protection
human activities cause land subsidence by compaction of aquifer systems
cannot be reversed - result in permanent reduction in storage capacity of aquifer system impacting overall flow + store of water
over-abstraction: Colorado
major river N America
flows through 7 states
area 250,000 square miles
river basin arid, extreme climatic diversity from alpine to desert
provide water to 40 mil for municipal use, irrigation and lifeblood for 22 federally recognised tribes
Hoover Dam: 1930 highest in US - built for flood control & irrigation
running dry, rarely reaches ocean in Gulf of California, one of most endangered rivers in US
human changes to water cycle: irrigation
drip: efficient, directs water to roots with little output via evaporation
spray: require more water, less efficient, cheaper
mismanagement: over-abstraction cause salinisation, salt get into groundwater stores
eutrophication
human changes to water cycle: drainage
drains poorly drained clay soils
increase productivity
warmer soils aid germination
air in soil increase biotic activity + breakdown organic matter
expensive
increase speed of through flow
nitrate loss through water lead to eutrophication
dry top soil susceptible to wind erosion
human changes to water cycle: ploughing
vertical & contour
River Exe - Devon
only 13% woodland
80% agriculture
4.5% urban
geology: 93.5% moderate/low permeability TMT less percolation, soils fill up quickly leading to increased runoff
River Exe - Mires Project
act to reduce climate change
peat drying & oxidising causing CO2 because drainage ditches
want to rewet peatland so absorb CO2
helps flood risk + increase water quality + increase habitats
block ditches so speed water reduced
River Exe - human activity
drainage ditches - encouraged for cattle use
Wimbleball Reservoir - slows water + provides supply
agriculture - cattle compact soil can’t hold much water decrease infiltration capacity
peatland restoration
River Exe - River Culm
longest tributary of Exe
catchment predominantly rural, comprising mixed woodland, agriculture
water quality failed to reach good chemical status because pollutants from agricultural
river regime responds quickly to winter rain
flashy: geology - impermeable clay promote rapid runoff
flashy: soils - sandy soils - permeable
flashy: land use 87% agricultural (soil compaction),
flashy: urbanisation - 2017 gov announced ‘Garden Villages’ provide 5,000 new homes, shops, employment, schools, increase runoff (concrete, tarmac) - removal of veg
River Exe - River Culm - Sustainable Drainage Systems (SuDS)
reduce runoff from urban like Culm Garden Village
infiltration + water storage encouraged
runoff reduced: infiltration basins, detention pool, soakaways, green roofs, wetlands
impact of human activity & environmental change
1/2 world RF wiped for commercial farming, mining, loggings, settlements
atmo less humid as evapotranspiration reduced
rain reaches ground immediately, compacting it - overland flow
exposed to sun, dry soil, vulnerable to erosion (desertification)
rates of runoff increase with increased risk of flooding
Africa’s Great Green Wall - Afforestation
Acacia trees thrive semi-arid
spans across 11 countries (Sahel)
8,000km long
Senegal most progress
began 2007
cost $8 billion
Africa’s Great Green Wall - Afforestation - benefits
more jobs - more eco stable
absorbs C & emits O2 (global scale)
provides shade so other plants grow to eat/sell
wells fill up (kids go to school don’t travel for water)
roots hold water & soil so nutrients kept for future plant growth
cheap & easy for locals to be involved
global stores of carbon
lithosphere (organic matter in soil (pedosphere), inorganic carbon in fossil fuels & sedimentary rocks)
hydrosphere (dissolved atmo CO2, weathered from rocks into rivers, calcium carbonate from shells)
cryosphere (CO2 stored in ice + peatbogs within permafrost regions)
atmosphere (gas CO2)
biosphere (living matter)
carbon transferred round carbon cycle - photosynthesis
CO2 taken in from atmo - reacts with chlorophyll produce glucose
CO2 + H2O -> C6H12O6 + O2
carbon dioxide + water + sunlight -> glucose + oxygen
equator lots photo - N Africa little photo + 2 poles
EU summer photo more often in N hem and during EU winter photo most often S hem
carbon transferred round carbon cycle - respiration
O2 + C6H12O6 -> energy + H2O + CO2
occurs in urban areas + farming - little in poles
carbon transferred round carbon cycle - decomposition
decomposers (detritovores) consume dead organic matter
CO2 released during process + organic material transfer into soil
where lot of life (RF) specifically RF floor
more in summer
carbon transferred round carbon cycle - weathering
breakdown of rocks in situ
CO2 dissolves in rain forming weak carbonic acid
CO2 + H2O -> H2CO3
acid dissolves rock on earth surface (chemical weathering)
carried by water, underground + by rivers to sea + settles as calcium carbonate
carbon transferred round carbon cycle - combustion
forest ecosystems usually balance absorb & release
3-4million km2 forest burnt each year release more than GTc per year
spatial: forest areas, hot, dry
temporal: local summer
carbon transferred round carbon cycle - burial & compaction (biological pump)
CO2 in phytoplankton
when die, sink deep & decay - form layers C rich sediment
over million years organic sediments buried + compacted form carbonate rocks e.g. limestone + hydrocarbon e.g. coal, oil, gas
carbon transferred round carbon cycle - organic carbon pump
2 way transfer between ocean & atmo
inverse relationship between water temp + ability to dissolve - water temp increase ability to dissolve CO2 decrease
carbon budget
uses data describe amount of C stored & transferred on C cycle
measured in petagrams (Pg)
carbon and land
carbon cycle responsible formation & development of soil - C in form of organic matter introduces nutrients + provides structure to soil
carbon and ocean
C converted to calcium carbonate used by marine organisms to build shells
C cycle impact presence & proliferation of phytoplankton - consumes CO2 - C passed along food chain
carbon cycle significant regional impacts on climate
vegetation - impacts global climates by removing CO2 + releasing water + O2 - regions with dense veg (RF) high rates of photo & respirational, increase humidity + cloud cover, affect regional temps and rain
regions experiencing deforestation drier + less humid - fewer trees less photo
proliferation of plankton promote formation of clouds through chemical substance DMS
volcanic eruptions release CO2 into atmo + ash + other gases - absorb more radiation lead to cooling effect (volcanic winter)
role of water and carbon in supporting human life
C one of 6 crucial elements in humans - 18% human body - stored form of glucose, assist cellular respiration
trees: C 50% biomass
atmo store water + C - all organisms need water - C in atmo essential for photo create carbohydrates needed plant growth + provide sufficient atmo warm
relationship between water cycle and carbon cycle
ability of water to absorb & transfer CO2 e.g. CO2 soluble in water
absorbtion of C in rain - pure water pH 7.0 - unpolluted rain mildly acidic pH5.6 - acidic rainwater affects weathering - dissolved C carried by river to ocean for shell growth + buried form new limestone deposits + some back to atmo
water cycle feedback loop
ice reflects radiation from Sun less heat absorbed
Arctic ice shrinking exposing more water - warmer water + further melts
local & regional impact: precipitation patterns & availability of fresh water
political & eco implications: no Arctic ice affect trading routes, exploitation of resources
carbon cycle feedback loop
higher temp increase growing season increase absorption of C
high temp melt permafrost - organic matter trap in frozen ground act C store - estimated more C trapped in permafrost than atmo - on melting, organic matter decompose
Arctic act net carbon store - if scale permafrost melting increase balance tip so Arctic become net C source (-tive feedback)
water cycle/carbon cycle feedback loop
phytoplankton & terrestrial plants use sun energy + CO2 (dissolved in water) to photo
phytoplankton release DMS promote formation of clouds (condensation) over oceans - increase in photo associated with warmer temps + more sun lead to increase cloud & global cooling bc clouds decrease solar radiation BUT less sun lead to decrease phytoplankton thereby decreasing cooling effect
mitigating impacts of climate change: carbon capture and storage
tech capture CO2 emission - gas transported to site where it’s stored - could cut C emissions by 19% - once captured gas compressed &transported by pipeline to injection well, injected as liquid into geological reservoirs
mitigating impacts of climate change: modifying photosynthesis
trees C sinks, remove CO2
trees release moisture into atmosphere + help moderate climate
plantation forests effective in absorbing CO2 compared to natural forests - recognised by IPCC as legit option for countries wishing to reduce C emissions
mitigating impacts of climate change: modifying deforestation
consumers encouraged buy wood certified by Forestry Stewardship Council (timber grown sustainably)
countries/organisations make C offset payments to offset their C emissions
Malaysia: Selective Management System sustainable approach to logging by felling selected trees + planting replacements
mitigating impacts of climate change: government policies in Brazil
landowners required preserve 80% virgin forest
government created protected reserves in Amazon along frontier areas where deforestation started
decrease deforestation by 70% which decrease C emissions more than any other country
mitigating impacts of climate change: political initiatives (Paris Agreement)
195 countries adopted first universal legally binding global climate deal
aim limit average global temp increase to 1.5.C
meet every 5 years to set more ambitious targets
human causes to changes in C cycle: combustion of fossil fuels
C locked up in deposits, when burnt to generate energy stored C released
since Industrial Revolution, fossil fuels burnt increasing quantities, pumping CO2 into atmo - enhances greenhouse effect, increase global temp
human causes to changes in C cycle: land-use change
responsible for 10% C release globally
farming practices: ploughing & harvesting, rearing, machinery & fertilisers release C - methane emitted as livestock regurgitate food + masticate 2nd time (cattle USA emit 5.5 mil tonnes of methane per year) - methane cultivation of rice (rice primary food source for 50% world’s pop)
human causes to changes in C cycle: urbanisation
globally urban areas occupy 2% total land area
major source of emissions transport, development of industry, conversion of land use from natural to urban + cement production
cement used in construction - CO2 by-product of chemical conversion process - contributes 2.4% global C emissions
atmospheric carbon - impacts of greenhouse effect
temp distribution - diff locations receive diff levels solar energy - angle sun’s rays result equator receiving most concentration radiation, whilst Poles same radiation dispersed over greater distance
albedo effect - white snow/glaciers/ice caps reflect hear - dark oceans/forests absorb heat
precipitation distribution - heating surface warm air rises cools condenses forming clouds - intense solar radiation at equator leads to warm air rising causing high levels rainfall - at 30.N/S air cools & sinks high pressure rain rare - at 60.N/S diff air masses meet resulting in frontal rain - Poles cold air sinks little rain
effects on changing carbon budget impact on land
increase temps increase growing seasons absorbing CO2
carbon fertilisation - more CO2 more photo and plant growth
tundra regions thaw permafrost leads to more rapid decomposition and release of CH4
global warming lead to dry conditions, increase forest fires, release CO2 - management lead to more fires extinguished - leads to build up woody material (C store) but make future fires worse
effects of changing carbon budget impact on oceans
ocean acidification - CO2 diffuses into ocean create carbonic acid react with carbonate ions form bicarbonate TMT less carbonate ions for coral and planktonic species to build shells
coral reefs- 500mil dependent for food & livelihoods - natural sea defence
warmer oceans hold less CO2 - decrease phytoplankton - reduce bio carbon pump - CO2 essential for plant and phytoplankton growth - bleaches coral
melting sea ice & sea level rise
natural factors changing carbon cycle
- Milankovitch cycles
- volcanic activity (emit 130-380mil tonnes CO2 per year) (super volcanic eruption could cause massive flux on C in atmo e.g. Yellow Stone)
- Wild Fires (turn forest from sink to source - 3-4mil km2 burnt each year releasing more than GTc per year)
tropical RF & carbon cycle
warm & wet climate ideal for growth - promote photo + absorb huge quantities of CO2
decomposition active process - bacteria & fungi thrive warm & wet - release CO2
C stored soil or dissolved removed by stream
impact of deforestation on CC - Indonesia
1960s: 80% RF but rapid development decimated forest
more than mil hectares cleared each year with 30% in C-rich peatland forests - once exposed peatlands easily eroded by wind/rain - no longer sink but source
prevalence of fires - send black smoke into atmo releasing huge quantities of C stored
world’s 3rd largest emitter of greenhouse gases - 85% emissions derived from RF + peatland degredation
Indonesia - background knowledge
over 13,466 islands - hard to police
267 million
3rd largest rainforest after Amazon and Congo
3rd largest emitter Greenhouse Gases after China and USA
Indonesia - deforestation
demand for toilet paper, biofuels, vegetable oil, mining, logging
increased risk drought, flooding, fires
rate of deforestation: 1900 89% cover, 1960 80% cover, 2000 53%, now under 1/2 original cover remains - nearly mil hectares cut each year
people turn to illegal logging because poor education so not good job opportunities - support family - follow father
Indonesia - monoculture
cloned acacia trees slows C cycle
photo occurs but operates at less effective levels - animals can’t survive in this envi
Indonesia - peat
peat soil layer 10m deep
when decomposed it releases C
Indonesia - water table
decreasing because of deforestation and over pumping of groundwater
Indonesia - fires
bad in 1997-1998 because El Nino (dry season brought drought + sparked fires) - low law enforcement - coincided with economical and political upheaval, downfall of President - ordered clearance of 1 million hectares of peatland to grow rice
bad in 2015: 2.6 mil hectares of forest destroyed - cost $16bil - smoke engulfed neighbouring countries so air quality exceeded max level of 1000 on national pollutant index (more than 3x amount considered hazardous) - visibility less than 5m, embers jumped across rivers
Indonesia - protecting forest
Peat Restoration Agency - role rewet most vulnerable peatland - cover more than 2mil hectares
Katingan Mentaya Project: aims protect & restore peatland forest - 157,000 hectares, provide sustainable livelihood, make profit for companies, move C, better education
multinationals: VW & Shell rewarded with carbon credit payments in return for saving forest - helps VW & Shell achieve own climate goals
One Map Policy
Indonesia - protecting forest - One Map Policy
helps resolve overlapping claims - put accurate info on land concessions to reduce chances of dispute over issue of permits for forest conservation, plantation, mining - help resolve problem illegal plantations - not successful largely closed off from public so instead offering more clarity created more confusion - no clear direction from govm or coordination ministry who need to resolve overlapping and conflict - lack of transparency: govm not released concession maps so diff to understand root of problem which is urget because of growing effects of climate change
