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Water and carbon cycles case studies - Coggle Diagram
Water and carbon cycles case studies
The amazon
Where
World’s Largest tropical rainforest
covers 40% of the South American landmass
Hot wet climate
Vegetation very dense
The Amazon is a rainforest in South America
details
Many groups of indigenous people
1 million plant species
over 500 mammal species
over 2000 fish species
Many endangered animals e.g black caiman, Amazonian manatee, pirarucu
Physical components
Carbon cycle
stores lots of carbon in its vegetation and soil- carbon sink
increasing concentration of CO2 in the atmosphere
led to increased productivity in the Amazon rainforest because the vegetation is able to access more CO2 for photosynthesis
amount of biomass is increasing
Amount of CO2 sequestered has increased making it an even more important carbon store
suggested that although trees are growing quicker, they’re dying younger
may not be able to rely on the amazon rainforest to continue to be such an effective carbon sink in the future
Water cycle
causes the amazon to be very wet
wet air is blown over the amazon and contributes to the very high rainfall
a lot of evaporation over the Atlantic ocean
Warm temperatures mean that evaporation is high in the actual rainforest too- also increases the precip
Dense canopy
means interception is high
less water flows into rivers than might otherwise be expected, and it does so more slowly
Species are adapted to high humidity and frequent rainfall
Human activites effects
deforestation
water cycle
no tree canopy to intercept rainfall
more water reaches the ground
too much water can soak into the soil so it becomes surface runoff
increased risk of flooding
Reduced rate of evapotranspiration (evaporation from everywhere basically)
means less water vapour reaches the atmosphere
fewer clouds and less rainfall
increased risk of drought
carbon cycle
without roots to hold the soil together heavy rain washes away nutrient rich top layer of soil
transferring carbon into the hydrosphere
less leaf litter
humus isn’t formed
soil can’t support much new growth
limits the amount of carbon that is absorbed
Trees remove CO2 from the atmosphere and store it
so fewer trees means more atmospheric CO2 which enhances the greenhouse effect and global warming
Climate change
Temperature is increasing
rainfall is decreasing
leads to drought
severe drought in 2005, 2010 and 2015
Plants and animals like it moist
so many die in dry weather
frequent or long drought periods could lead to extinctions
also lead to forest fires, destroying large areas of forest and releasing a lot of CO2
Predicted 4 degree temp rise could kill 85% o the rainforest
would result in a lot of carbon being released into the atmosphere as the dead material decomposed
less CO2 taken in from the air for photosynthesis
attempts to limit human impacts
selective logging
only some trees are felled
less damaging to the forest than felling all trees in an area
if only a few trees are felled then the structure still remains
canopy is still there and the soil isn’t exposed
means forest can regenerate and the impact is smaller
replanting
new trees were planted to replace the ones cut down
e.g in Peru (photo) 115 acres were replanted between 2016-19
important that the same type of tree is planted so the variety of the trees is kept
water and carbon can eventually return to their original state
environmental law
Laws ban the use of wood from forests that are not managed sustainably
ban excessive logging
control land use
e.g Brazillian forest code says landowners have to keep 50-80% of their land as forest
protection
set up national parks and nature reserves
Central Amazon Conservation Complex
set up in 2003 and protects biodiversity
area of 49 000 km2
allows locals to use the forest sustainably
Within parks damaging activities like logging can be monitored and prevented
The river Exe
Mire on the moore project
restore 2000hs of Exmoor to the boggy conditions that would naturally be present by blocking drainage ditches with peat blocks and moorland bales
benefits
more water storage in upper catchments- water transfer is slowed increasing storage capacity and ensuring a steady supply of water throughout the year
improved water quality- slower throughflow means that less sediment is carried into rivers. water is cleaner, less expensive to treat and good for wildlife
more carbon storage- peat is essentially carbon and water and therefore an important carbon store. dry peat releases Co2 through oxidation. by encouraging the re-wetting and active peat growth CO2 is naturally absorbed and stored
improved opportunities for education leisure and recreation. peatland habitats are very biodiverse and with many species
improved grazing and water supply for animals- animals benefit from having year-round drinking water as well as improved grazing during the drier parts of the year
water balance
runoff is 65 % of water balance is due to impermeable rock not allowing much percolation or baseflow
drainage ditches on Exmoor reduce the amount of soil water storage
River exe past
during 19th and 20th centuries huge swathes of upland peat bigs were drain as a part of a nationwide effort to increase flagging agricultural productivity
peat is good for growing but not when water logged
draining it increases agricultural productivity
however it doesn't store the water anymore
in the 1970s the Winble reservoir was built to ensure continuous water supply to customers in Exeter
low rainfall in summer months and climate change causing more evaporation the water level in Wimbleball has dropped considerably recently
estimated cost of a 2nd reservoir is like £90 million
River exe details
85 % of the basin is made of impermeable rock
doesn't allow water to pass through
water is most likely to flow across the top
floods a lot
high drainage density making up the tributaries and main river of the basin
where?
source at Exe Head near Simonsbath
8km from the bristol channel
flows into English channel at Exmouth
Area of upper cacthment is 60km2
maximum elevation of 514 in the north
land is much flatter in the south, lowest elevation of 26m
most of the land is agricultural grassland
15 % woodland
13 % arable farmland
only a small amount is urban in the south
annual rainfall ranges form more than 2300mm in the north to less than 800mm on the coast
in England and Wales average is 920mm
in the north, the river exe and Barle rise on the open wet moorland of Exmoor and flow southeast through steep sided valleys
rivers confined to steep narrow valley that respond rapidly to rainfall