Amazon Case Study Water and Carbon Flashcards
(41 cards)
how much area does the Amazon rainforest cover?
6 million km2
what type of trees are in the Amazon rainforest?
tall, evergreen, hardwood
what are the average annual temperatures?
between 25-30 degrees C
high
is there much seasonal variation in temperature?
no
what is the annual average rainfall like?
high
>2000mm per year
how much precipitation is recycled by evapotranspiration in the Amazon?
50-60%
what are the characteristics of precipitation in the Amazon?
high average rainfall, <2000mm
evenly distributed throughout the year
high intensity convectional rainfall
forest tress intercept 10%
intercepted rainfall accounts for 20-25% of all evaporation
what are the characteristics of evapotranspiration in the Amazon?
high rates of evaporation and transpiration due to high temperatures, abundant moisture and dense vegetation
strong evapotranspiration-precipitation feedback loops sustain high rainfall totals
50% of incoming rainfall is returned to the atmosphere by evapotranspiration
most evaporation is intercepted moisture from leaf surfaces
most moisture lost in transpiration is derived from the soil via tree roots
what are the characteristics of run-off in the Amazon?
rapid run-off is related to high rainfall, intensive rainfall events and well-drained soils
river discharge may peak in one or two months of the year
what are the characteristics of atmosphere in the Amazon?
high temperatures allow the atmosphere to store large amounts of water
absolute humidity is high
relative humidity is high
what are the characteristics of soil/groundwater in the Amazon?
abundant rainfall and deep tropical soils leads to significant water storage in soils and aquifers
what are the characteristics of vegetation in the Amazon?
rainforest trees absorb and store water from the soil and release it through transpiration.
how many tonnes of carbon is absorbed by the Amazon Rainforest?
2.4 billion/year
how many tonnes of biomass is in the Amazon?
400-700 tonnes / hectare
why are exchanges of carbon between the atmosphere, soil and biosphere so quick in the Amazon?
warm humid conditions means that there is a quick rate of decomposition of dead organic matter and quick release of CO2
meanwhile, rates of carbon fixation through photosynthesis
the Amazon has the highest NNP and biomass of all terrestial ecosystems.
what is NPP?
net primary productivity
how does geology effect the flood hydrograph?
impermeable catchments have minimal water storage capacity, resulting in rapid run off
permeable and porous rocks such as limestone and sandstone store rainwater and run off.
how does relief effect the flood hydrograph?
Most of the Amazon Basin is on extensive lowlands
in areas of gentle relief water moves across the surface, overland flow
or horizontally through the soil, throughflow
widespread inundation across extensive floodplains occurs annually, storing water for several months and slowing its movement into rivers
how does temperature effect the flood hydrograph?
high temps all year generate high levels of evapotranspiration
convection is strong, leading to high atmospheric humidity, development of thunderstorm clouds and intense precipitation
water is continuously cycled between the land surface, forest and the atmosphere by evaporation, transpiration and precipitation
how much carbon is stored in the amazon rainforest?
100 billion tonnes
how much carbon does the Amazon release by decomposition?
1.7 million tonnes/year
what percentage of the Amazons carbon is stored above ground, and where?
60%
tree stems, branches and leaves
how does temperature effect the stores and flows of carbon?
stimulate primary production
NPP averages about 2500 grams/m2/year
Amazon alone accounts for 15-25% of all NPP in terrestrial ecosystems
how do humid conditions effect the stores and flows of carbon?
promotes rapid decomposition of leaf litter and other dead organic organisms that accumulates on the forest floor
emits CO2