Water and carbon case studies

Question 1

Amazon water

Answer 1

• evaporation over Atlantic brings lots of rainfall
• evaporation is high due to high temperatures
• amazon makes 1/3 of own precipitation
• high interception due to dense canopy
• little runoff into river

Question 2

Amazon carbon

Answer 2

• carbon sink due to high vegetation and soil
• increase in CO2 in atmosphere leads to an increase in biomass as vegetation can access more CO2 via photosynthesis
• too much can cause younger trees to die earlier

Question 3

Amazon deforestation

Answer 3

• loss of tree canopy so increased runoff as soil becomes saturated
• reduces evapotranspiration
• slash and burn reduces carbon storage and turns rainforest into carbon source not sink
• last 50 years, 17% vegetation lost
• lack of root-stabilising soil means heavy washes away nutrients in soil
• less leaf litter means no humus formed so new growth not supported

Question 4

Amazon climate change

Answer 4

• temp increase, rainfall decrease leads to drought
• plants and animals die due to dry weather
• can lead to extinction of some species
• droughts can lead to forest fires which cause large amounts of CO2 to be released into atmosphere
• as more of the rainforest is killed, dead matter decomposes and releases more CO2

Question 5

Amazon reversing/mitigating impacts

Answer 5

• selective logging
• replanting
• environmental laws - Brazilian forest code (landowners must keep 50-80% of land as forest)
• central amazon conservation complex - allows people to use forest in a sustainable way
• carbon offsetting (large companies are paid to plant trees in place of carbon they emit)

Question 6

River Exe impact of tributaries

Answer 6

• 5
• high drainage density
• leads to rapid surface runoff

Question 7

River Exe physical features of drainage basin

Answer 7

• land is flatter in south
• drainage basin has low infiltration rate
• increased surface runoff
• lots of precipitation = high peak discharge

Question 8

River Exe geological characteristics

Answer 8

• mostly impermeable rock
• little infiltration
• lots of surface runoff

Question 9

River Exe land use

Answer 9

• agricultural, woodland + arable
• on high ground there are moor and peat bogs (decrease surface runoff and water is stored slowly)

Question 10

River Exe human activity

Answer 10

• the Wimbleball Reservoir
• dam regulates water flow
• makes flooding and droughts less likely

Question 11

River Exe peat restoration

Answer 11

• Exmoor Mires Project
• blocks drainage ditches
• increases water content
• retains carbon stored in peat

Question 12

River Exe human impacts negative

Answer 12

• increased water flow due to drainage ditches being dug
• peat is dug as fuel leaving ugly scars in landscape
• as peat dries, decomposition occurs releasing CO2 and methane

Question 13

River Exe advantages of peat restoration

Answer 13

• increased water storage
• improved water quality
• more carbon storage
• improved education
• improved grazing and water supply