Tropical Rainforest: Amazon CS Flashcards
(35 cards)
Where are Tropical rainforests located globally?
All between the tropic of cancer and tropic of Capricorn
Vast majority found within 10 degrees north and south of the equator
3 background info facts about the Amazon rainforest
Covers 8.2 million km^2
It is the largest single source of fresh water runoff
absorbs around 35% of the world’s CO2 emissions, produces more than 20% of the world’s oxygen
2 evaluations of climate graphs
Monthly data hides variations within the month
Doesn’t take spatial variations into account
What’s the inputs in the Amazon’s water cycle?
Precipitation
Prevailing wind directions
3 facts about The Amazon’s precipitation
10% of rainfall is intercepted
50-60% of precipitation in Amazonia is recycled by evapotranspiration in a strong feedback loop
High rainfall over 2000mm
How does prevailing wind direction impact The Amazon’s water cycle?
The wind direction can influence ocean currents and push the evaporated water vapour towards the Amazon leading to high precipitation
What’s the outputs from the Amazon rainforest’s water cycle?
River discharge into the ocean
Evapotranspiration
2 Facts about the Amazons river discharge
175,000 m3 per second
1/5th of the total discharge into the oceans of all of the world’s rivers
2 Facts about Evapotranspiration in The Amazon rainforest
Most evaporation is from interception moisture on leaf surfaces
2/3 of precipitation that falls goes back up through evapotranspiration
3 Factors behind high rates of Evapotranspiration
High temperatures
Abundant moisture
Dense vegetation
What are the 4 Flows/stores in the Amazon Water cycle?
Run-off - high during high rainfall events
Atmosphere - higher temps mean more storage of water in the air
Soil/groundwater - rainfall means abundant storage in soil and aquifers
Vegetation - Trees play a crucial role absorbing and storing water from the soil and
releasing it through transpiration
What are the 3 physical Factors that affect stores and flows of water in the Amazon?
Geology
Relief
Temperature
How does geology impact the flows and stores of water in the Amazon?
Much of the underlying rock in the Amazon is impermeable igneous and metamorphic rock
This limits water storage and increases rapid run-off
How does Relief impact the flows and stores of water in the Amazon?
Most of the Amazon basin is extensive Lowland
In areas of gentle relief, water moves across the surface (overland flow) or horizontally through the soil (throughflow) to streams and rivers
How does Temperature impact the flows and stores of water in the Amazon?
temperatures between 25-28oC throughout the year generate high rates of evapotranspiration
strong Convection leads to high atmospheric humidity, the development of thunderstorm clouds (cumulonimbus)
and intense precipitation
What are the rates of Deforestation in the Amazon?
Between 1970 – 2013 around 17,500km2/yr.
1/5th of Primary Forest destroyed or degraded
What are 3 effects of deforestation on the Amazon’s water cycle?
Increased run-off - converting rainforest to grassland increases rates of run-off by factor of 27
Decreased storage - 1/2 of rainfall on grassland goes directly to rivers compared to nearly all rainfall remaining in an area of rainforest
Breaking the regional water cycle that keeps atmospheric humidity high which then leads to clouds and rain
How does farming effect the Amazon’s water cycle?
increased need for land means that there is an increase in deforestation
3 ways the Amazon rainforest is a carbon sink
Major store of global carbon, absorbing 2.4 billion tonnes per year
Net primary Productivity (NPP) is high
Carbon exchange between the atmosphere, biosphere and soils is rapid
What are the 3 Physical Factors affecting stores and flows of Carbon in the Amazon?
Temperature
Vegetation
Organic matter in soil
How does Temperature affect stores and flows of Carbon in the Amazon?
Warm temperatures = quick decomposition of dead organic matter AND quick release of CO2
Also enables high levels of primary production
How does Vegetation affect stores and flows of Carbon in the Amazon?
NPP averages around 2,500 grams/m2/yr
Rainforest Trees store around 180 tonnes of carbon/hectare + another 40 tonnes in their roots
In total, trees in the Amazon store around 100billion tonnes of carbon
How does organic matter in soil affect stores and flows of Carbon in the Amazon?
Soils average between 90-200 tonnes of carbon/hectare
Amazonia’s leached and acidic soils contain only limited carbon and nutrient stores
Such poor soils only manage to support the biome due to the speed in which organic matter is broken down and recycled
What are the Human factors affecting stores and flows of Carbon in the Amazon?
Deforestation
