Water & Carbon Cycle stores & flows at Amazon Rainforest

Amazon rainforest is dominated by what kind of trees?

Tall, evergreen, hardwood trees

Annual temperature ranges between and __

25–30°C

Seasonal variation in temperature is large / small

Small

Explain why average temperature is high but doesn’t reach the extremes of the sub-tropical desert climates. (2M)

Intense insolation near the equator year-round and significant cloud cover prevents temperature extremes

Average annual rainfall exceeds

2000 mm

Name the type of rainfall found

Convectional rainfall

What percentage of precipitation in Amazonia is recycled into the atmosphere?

50–60%

Name the process which recycles precipitation into the atmosphere from the soil moisture store

Transpiration

Explain why the process above is particularly sizeable given the vegetation structure of the Amazon rainforest (Bonus – 2M)

Continuous evergreen canopy provides a large leaf surface area, increasing transpiration

Interception by forest trees takes up what % of precipitation?

About 10%

Intercepted rainfall accounts for what % of all evaporation?

20–25%

Give 3 reasons for high rates of evaporation & transpiration (3M)

High temperatures, abundant moisture, dense vegetation

Name the feedback loop which sustains high rainfall in the Amazon rainforest

Evapotranspiration–precipitation feedback loop

How much precipitation is returned to the atmosphere by evapotranspiration?

Around half

Where does most of the evaporation come from?

Intercepted moisture from leaf surfaces

High temperature allows the atmosphere to store large amounts of moisture. Name the key term which describes this

Absolute humidity

Tropical soils in the Amazon rainforest are deep / shallow, this leads to a small / large soil moisture store (2M)

Deep soils, large soil moisture store

Outline two ways water is output from the Amazon drainage basin (2M)

River discharge and export of atmospheric water vapour

Outline 1 water input to the atmospheric store above the Amazon drainage basin

Moisture influx from the Atlantic Ocean

What is the net primary productivity at Amazonia? (1M quantity, 1M unit)

~2500 g/m²/year

Name the impermeable catchments in the Amazon Basin, and the type of rock found there (2M, bonus 2M for regions)

Ancient shields (Guyana Shield, Brazilian Shield), crystalline rocks

Name the permeable & porous rocks found in the Amazon Basin (2M). Where are they found? (1M)

Sandstone and limestone, located between the ancient shields

Describe the relief in the Amazon Basin (3M)

Extensive lowland plains, steep Andes relief to the west, large floodplains (e.g. Pantanal)

Explain why speed of decomposition is rapid in the Amazon rainforest (2M)

High rainfall and consistently high temperatures

What is the total amount of CO₂ taken in by the Amazon rainforest from the atmosphere each year?

~2.5 billion tonnes

What is the quantity of carbon stored as biomass in Amazon tropical rainforest (tonnes/ha)?

~400–700 tonnes per hectare

What is the biggest carbon store in the Amazon rainforest?

Biomass

Explain why the size of the carbon store in soil is small. Give two reasons

Rapid decomposition and uptake by vegetation, plus leaching due to heavy rainfall

Explain why nutrient-poor soil is able to support high NPP

Rapid nutrient cycling and high leaf litter input

Identify a temporary carbon store in the Amazon rainforest and the location of limestone outcrops in the Amazon

Dead organic matter (leaf litter) - western part of amazon basin, close to andes

Name the process which releases CO₂ when reacting with limestone

Carbonation