OCR A Level ELSS - 7 OCR A Level ELSS 4.2 Amazon Rainforest CASE STUDY Flashcards
What is the area of the Amazon rainforest?
6 million km2
How significant is the Amazon rainforest regarding freshwater in the water cycle?
The amazon river basin is the largest single source of freshwater runoff on Earth, representing 15-20% of global river discharge
How significant is the Amazon rainforest as a carbon sink in the global carbon cycle?
The Amazon rainforest absorbs around 35% of global CO2 emissions and produces more than 20% of the world’s oxygen
What percentage of the Amazon rainforest is in Brazil?
70
What is the average annual temperature in the Amazon rainforest?
25-30 degrees C
What is the average annual rainfall in the Amazon rainforest?
> 2000mm
Why does the Amazon have a humid and tropical climate?
It’s location near the equator means that it has some of the highest levels of solar insolation. This means that the earth’s surface heats up and warms the surrounding air. Consequently, the warm air rises, cools and the water vapour condenses forming clouds. Latent heat allows air to continue to rise and so storm clouds form, resulting in high precipitation levels in this region. The thermal equator (ITCZ) moves with the tilt of the earth, meaning that there is a dry and wet season in the tropics.
What percentage of precipitation is recycled by evapotransipiration?
50-60
What percentage of precipitation is intercepted by forest trees in the Amazon rainforest?
10
What percentage of evaporation comes from intercepted rainfall in the Amazon rainforest?
20-25
What causes high rates of transpiration in the Amazon rainforest?
high temperatures abundant moisture dense vegetation
How much of incoming rainfall is returned to the atmosphere by evapotranspiration in the Amazon rainforest?
half
Why can run-off be high in certain parts of the Amazon rainforest?
- Rainfall is often falls in intense afternoon storms. 2. Where there has been deforestation, there is less interception and so rainfall quickly saturates the thin soil layer and creates significant amounts of run-off. 3. Large parts of the Amazon have an underlying geology of impermeable igneous and metamorphic rock, which do not allow water to infiltrate and so increases the rates of run-off.
Where is moisture lost in transpiration derived from?
soil via tree roots
What are the significant water stores in the Amazon rainforest?
soils and groundwater
What role do rainforest trees play in the water cycle in the Amazon rainforest?
absorb and store water and release it through transpiration
What enables the air in the Amazon rainforest to store large amounts of moisture?
warm air is able to hold more moisture than cold air and the air in the Amazon rainforest is warm due to the high levels of solar insolation.
What is the net primary productivity average in the Amazon rainforest?
2500 grams/m2/year
What is the biomass per hectare in the Amazon rainforest?
400 and 7000 tonnes/ha
What is the typical amount of carbon in large forest trees above ground store in the Amazon rainforest?
180 tonnes C/ha
What is the typical amount of carbon stored by trees below ground (i.e. roots) in the Amazon rainforest?
40 tonnes C/ha
What is the typical amount of carbon stored in the soils in the Amazon rainforest?
90-200 tonnes/ha
How much carbon does the amazon rainforest absorb each year?
2.4 billion tonnes
What ensures speedy decomposition of dead organic matter and the quick release of CO2 in the Amazon rainforest?
warm, humid conditions
What makes carbon exchange rapid in the Amazon rainforest?
fast decomposition and fast photosynthesis
What is limited in Amazonia’s leached and acidic soils?
carbon and nutrient stores
What three physical factors affect flows and stores of water in the Amazon rainforest
geology, relief and temperature
What effects do the underlying geology of the Amazon Rainforest basin have on the water cycle??
The large parts of the Amazon that have an underlying geology of impermeable igneous and metamorphic rock, do not allow water to infiltrate, and so there is increased rates of run-off in these parts. Where there are more porous areas of limestone and sandstone, more water is stored in underground aquifers and there is slower run-off.
How does water move in areas of gentle relief in the Amazon rainforest?
across the surface (overland flow) or horizontally through the soil (throughflow) to streams and rivers
What is an example of a floodplain which stores water for several months due to gentle relief in the Amazon rainforest?
Pantanal
What impacts do the Andes mountains (areas of high and steep relief) have on the water cycle in the Amazon rainforest?
The steep slopes of the Andes create areas of rapid run-off, making precipitation flow quickly through this part of the drainage basin. The Andes also physically block the movement of warm, moist air from the east (as part of orographic uplift/relief rainfall), consequently, there is heavy rainfall throughout the year in the Andes, creating many tributaries that all lead to the Amazon river.
What evidence is there that the majority of the Amazon river basin’s elevational gradient is very low?
The mouth of the Rio Negro river (a tributary of the Amazon river) is 1,500km from the Atlantic, and yet is still only 15m above sea level. Therefore the gradient is about 1cm for every kilometre along the rest of the river from this point!
What is the name given to strong air circulation currents that are active in the Amazon rainforest that lead to high atmospheric humidity, the development of thunderstorm clouds and intense precipitation?
convection
How much carbon is locked up in the Amazon rainforest?
100 billion tonnes
What is the main carbon store in the Amazon rainforest?
forest trees
How much carbon is released a year through decomposition in the Amazon rainforest?
1.7 billion tonnes
Which process connects the rainforest to atmosphere stores?
photosynthesis
What percent of all carbon in the Amazon rainforest is stored in the above ground biomass of tree stems, branches and leaves?
60
What stimulates primary production in Amazon rainforest?
high temperatures high rainfall intense sunlight
What percent of all NPP in terrestrial ecosystems does Amazonia account for?
15-25
How is organic litter decomposed in the Amazon rainforest?
bacteria fungi other soil organisms
What is the geology of Amazonia dominated by?
ancient igneous and metamorphic rock
What was the average rate of deforestation between 1970 and 2013 in the Amazon rainforest?
17,500 km2/year
Since 1970, what fraction of the primary forest in the Amazon Rainforest has been destroyed or degraded?
one-fifth
On which river did devastating floods occur in April 2014?
Madeira River
What was the record level above normal that the river at Porto Velho reached?
19.68m
How many people died as a result of the 2014 flood on the Madeira river in the Amazon rainforest?
60
How many families were evacuated as a result of the 2014 flood on the Madeira river in the Amazon rainforest?
68,000
What diseases broke out as a result of the 2014 flood on the Madeira river in the Amazon rainforest?
cholera and leptospirosis
Where has deforestation reduced water storage in the Amazon rainforest?
- forest trees 2. soils 3. permeable rocks 4. atmosphere
What processes in the water cycle are reduced due to deforestation in the Amazon rainforest?
- evapotranspiration 2. interception and 3. precipitation
Deforestation in which countries was a main cause of the floods in the 2014 flood on the Madeira river in the Amazon rainforest?
Bolivia and Peru
How much of the Bolivian rainforest was cleared between 2000 and 2012?
30,000 km2
Why was Bolivian and Peruvian rainforest cleared between 2000 and 2012?
- Subsistence farming 2. Cattle ranching
What effect did the conversion of rainforest to subsistence farming and cattle ranching have on the Madeira drainage basin?
- Reduced interception 2. Reduced storage capacity of rainfall 3. Dramatically increased the rates of run-off
By what factor does run off increase by when converting rainforest to grassland?
27
How much rainfall falling on grassland goes into rivers?
half
What were the physical factors that contributed to the Medeira river floods in 2014?
- Extreme rainfall - between December 2013 - March 2014 rainfall was around 100% above normal. This led to river discharge being 74% higher than normal (58,000m3/second!) at Porto Velho. 2. Studies suggest that the extreme rainfall was caused by warm conditions in the western Pacific-Indian Ocean and with an exceptionally warm Subtropical South Atlantic
By what percentage is regional rainfall in Amazonia due to reduce by as a result of future projections of deforestation in Amazonia?
20
Which store does deforestation reduce in the carbon cycle?
carbon biomass store
What is the biomass of grasslands in areas of former rainforest?
16.2 tonnes/ha
What is the biomass in areas of soya cultivation?
2.7 tonnes/ha
By how much is Brazil committed to restoring to the rainforest by 2030?
120,000km2
What is eroded without the protection of forest trees?
soils
What type of methods did indigenous people in the Amazon rainforest survive as for thousands of years?
- Hunter-gatherers and 2. Shifting cultivators
How big is the area covered by the Amazon Regional Protected Areas?
twenty times the size of Belgium
What percent of Brazilian Amazon was national park, wildlife reserves or indigenous reserves by 2015?
44
What kind of assistance is given to smallholders for land preparation, planting and the maintenance of plots by the Parica project in Rondonia?
financial
What did the Surui project join in 2009?
UN’s Reducing Emissions from Deforestation and Degradation (REDD) scheme
Who does the REDD scheme give payments to and for what?
tribes for protecting rainforest and abandoning logging
Which agricultural technique maintains soil fertility in the Amazon rainforest?
diversification
What is an example of diversification in agricultural technique in the Amazon Rainforest?
- rotational cropping 2. combining livestock with crops
What is the expected level of increase in ranching productivity if diversification strategies are used?
fivefold
What are human-engineered dark soils made from?
charcoal, waste, human manure
What do dark soils attract that retains long-term fertility?
micro-organisms
What kind of assistance is given to smallholders for land preparation, planting and the maintenance of plots in the Amazon rainforest?
financial
