Amazon Rainforest

What is the average annual temperature in the Amazon Rainforest?

26–30°C.

What is the annual average rainfall in the Amazon?

About 2500 mm.

What process returns 50% of rainfall to the atmosphere?

Evapotranspiration.

What meteorological system causes high rainfall at the equator?

Convergence of Hadley cells.

What kind of system is the Amazon drainage basin?

Open system.

What are the main water inputs into the Amazon system?

Precipitation and inflows from tributaries.

What are the main outputs of water in the Amazon?

Evapotranspiration, runoff.

What climatic feature contributes to high convection in the Amazon?

High temperatures.

How do trees contribute to rainfall in the Amazon?

Through evapotranspiration and recycling of moisture.

How much carbon is stored in the Amazon rainforest?

100 gigatonnes (Gt).

What percentage of the Amazon’s carbon is stored above ground?

60%.

What percentage of the Amazon’s carbon is in soil and roots?

40%.

How much carbon is absorbed by photosynthesis annually in the Amazon?

2.4 Gt/year.

How much carbon is released through respiration annually?

1.7 Gt/year.

Is the Amazon currently a carbon sink or a source?

A sink (absorbs more than it emits).

What are the main factors influencing carbon sequestration in the Amazon?

Sunlight, warmth, rainfall, humidity.

What is the Amazon’s Net Primary Productivity (NPP) and what is that?

• 2500 g/m²/year.

• The net amount of chemical energy or carbon that plants and producers accumulate in their biomass accounting for respiratory losses

What kind of bedrock is mostly found in the Amazon?

Igneous and metamorphic.

Where in the Amazon is limestone found?

At the foot of the Andes.

Why is nutrient input from rocks low in the Amazon?

Most rocks lack carbon and minerals.

What is leaching, and how does it affect Amazon soils?

Rainwater dissolves minerals, leaving behind iron and aluminium.

What diagram is used to represent nutrient cycling in the Amazon?

Gersmehl diagram.

What trend was observed in a 2015 study of carbon sequestration?

Carbon uptake by Amazon forests declined by one-third since the 1990s.

Why is forest regrowth less effective at carbon sequestration?

It lacks the resilience and biodiversity of untouched primary forest.

What is the main cause of deforestation in the Amazon?

Cattle ranching.

What percentage of Amazon deforestation is due to cattle ranching?

80%.

What is the cattle density per hectare in the Amazon?

1 cow per hectare.

What are the production costs of Amazonian cattle ranching?

US$0.15/kg.

What happens to rainfall after deforestation?

It declines due to loss of evapotranspiration.

What happens to runoff when the canopy is removed?

Runoff increases by 27 times.

What happens to groundwater stores after deforestation?

They are not replenished.

What happens to ground temperatures after canopy loss?

They rise by 5°C.

How does cattle ranching affect soil?

Causes compaction, erosion, and degradation.

How does biomass loss affect the carbon cycle?

Less carbon is sequestered; atmospheric CO₂ increases.

Where is the Belo Monte Dam located?

On the Xingu River.

How much land was submerged by the Belo Monte Dam?

478 km².

How many turbines does the Belo Monte Dam have?

18 turbines.

What is the capacity of the Belo Monte Dam?

11,000 MW.

What happens to vegetation in flooded areas?

It rots, releasing methane and CO₂.

How does the dam affect fish populations?

Disrupts breeding due to loss of flood ponds and fruit access.

What is the impact of infrastructure like roads and power lines?

Fragments the forest and makes it more vulnerable to exploitation.

What is agroforestry?

Growing crops and trees together to benefit ecosystems.

Name three crops used in Amazon agroforestry.

Cocoa, bananas, coffee.

How does agroforestry benefit the carbon cycle?

Increases carbon storage through more vegetation.

How does agroforestry benefit the water cycle?

Maintains canopy cover, reduces erosion, improves infiltration.

What is a limitation of agroforestry?

May not be effective on a large scale or in all regions.

What is the size of Manu National Park?

17,000 km².

Why is Manu National Park effective for conservation?

Remote location, no roads, high biodiversity.

Who manages Manu National Park?

Peruvian environmental authorities under UNESCO designation.

What is the goal of Manu Biosphere Reserve?

Conserve ecosystems and support sustainable livelihoods.

What is the 'Muvuca' strategy?

Reforestation method using 200+ native seeds per square meter.

How many plants per hectare does the Muvuca method yield?

And using the muvuca method should result in a yield of 2,500 plants per hectare, rising to up to 5,000 after 10 years

How many times more efficient is the Muvuca seed strategy and when measured as plant per hectare compared to traditional methods and why?

• Around 15-30 times more efficient

• Around 2500-5000 plants per hectare compared to 160

• This is because it creates a highly dense, competitive environment designed to mimic natural succession, where the strongest saplings survive and form a resilient forest

Where is Instituto Terra located?

Minas Gerais, Brazil.

How many trees have been planted by Instituto Terra?

2.7 million.

What ecological impacts has Instituto Terra achieved?

Restored 8 water springs, 320 animal species returned, rainfall increased.

Where is half of the soil carbon pool held in tropical soils?

In the top 0.3 m – in the leaf litter and humus.

What happens to carbon and nutrients released from rapid decomposition in tropical soils?

They are taken up immediately by plants.

What is the threshold for Amazon dieback?

The threshold for Amazon dieback is 2 degrees Celsius warming and 20% deforested and currently it is 1.5 degrees Celsius warming and 17% deforested

What is Amazon dieback?

This topping point relates to the close coupling between the land ecosystem and the atmosphere, with the rainforest playing an important role in maintaining precipitation (and hence soil moisture) at levels sufficient to support rainforest and when this tips it will change from a rainforest to a savannah

What did COP 30 establish?

10 additional indigenous territories in the Amazon.

What has occured in Brazil with deforestation between 2022-2023 and what has continued after this?

Deforestation was halved from 2022 to 2023 and this decline continued in 2024 and 2025.

How much amazon was lost in 2023?

5,153 square kilometers of rainforest was lost around 722,000 football fields.

How can hydroelectric dams impact stores of carbon through sediment and soil?

Altered river flow reduces sediment transport, which can affect downstream floodplain soils that normally store organic carbon.

Synoptic idea on how hydroelectric dams impact the stores of carbon?

• Modified discharge of the Xingu River alters evapotranspiration and local moisture recycling.

• Reduced regional rainfall can stress surrounding forest, increasing tree mortality and fire risk, releasing further carbon.