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Earth's Life Support Systems > 2.a. It is possible to identify the physical and human factors that affect the water and carbon cycles in a tropical rainforest. > Flashcards

2.a. It is possible to identify the physical and human factors that affect the water and carbon cycles in a tropical rainforest. Flashcards

1
Q

Where is the Amazon rainforest located?

A

Located in South America.

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2
Q

How much area does the Amazon rainforest occupy?

A

More than 6 million km2.

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3
Q

What percentage of the Amazon rainforest is in Brazil?

A

70% of the rainforest is in Brazil, but extends to six other countries.

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4
Q

Amazonia is dominated by what kind of trees?

(The Rainforest Water Cycle)

A

Tall, evergreen, hardwood trees.

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5
Q

Outline the 3 climatic features within the Amazon rainforest.

(The Rainforest Water Cycle)

A

High average annual temperatures between 25°C and 30°C.

Small seasonal variation in temperature.

High average annual rainfall (>2000 mm) with no dry season.

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6
Q

What causes high average temperatures within the Amazon rainforest?

(The Rainforest Water Cycle)

A

Act as a response to intense insolation throughout the year.

However, significant cloud cover ensures that maximum temperatures do not reach the extremes of sub- tropical desert climates.

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7
Q

Outline seasonal differences in temperature, within the Amazon rainforest.

(The Rainforest Water Cycle)

A

Differences include small and convectional rain falls all year round, though most areas experience at least one drier period.

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8
Q

What percentage of precipitation in Amazonia is recycled by evapotranspiration?

(The Rainforest Water Cycle)

A

Between 50-60%.

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9
Q

Water losses from the Amazon Basin are caused by what? How is this loss of water made positive?

(The Rainforest Water Cycle)

A

Caused by river flow and exports of atmospheric vapour to other regions (evapotranspiration).

This loss is made good by an inward flux of moisture from the Atlantic Ocean.

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10
Q

Outline precipitation in the Amazon rainforest.

(The Rainforest Water Cycle)

A

High average annual rainfall (>2000 mm).

Rainfall fairly evenly distributed throughout the year though short drier season occurs in some places.

High-intensity, convectional rainfall.

Interception by forest trees is high (around 10 per cent of precipitation).

Intercepted rainfall accounts for 20-25 per cent of all evaporation.

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11
Q

Outline evapotranspiration in the Amazon rainforest.

(The Rainforest Water Cycle)

A

High rates of evaporation and transpiration due to high temperatures, abundant moisture and dense vegetation.

Strong evapotranspiration-precipitation feedback loops sustain high rainfall totals.

Around a half of incoming rainfall is returned to the atmosphere by evapotranspiration.

Most evaporation is from intercepted moisture from leaf surfaces.

Moisture lost in transpiration is derived from the soil via tree roots.

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12
Q

Outline run-off in the Amazon rainforest.

(The Rainforest Water Cycle)

A

Rapid run-off related to high rainfall, intensive rainfall events and well-drained soils. Depending on seasonal distribution of rainfall, river discharge may peak in one or two months of the year.

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13
Q

Outline atmosphere in the Amazon rainforest.

(The Rainforest Water Cycle)

A

High temperatures allow the atmosphere to store large amounts of moisture (i.e. absolute humidity is high). Relative humidity is also high.

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14
Q

Outline soil/ groundwater in the Amazon rainforest.

(The Rainforest Water Cycle)

A

Abundant rainfall and deep tropical soils lead to significant water storage in soils and aquifers.

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15
Q

Outline vegetation in the Amazon rainforest.

(The Rainforest Water Cycle)

A

Rainforest trees play a crucial role in the water cycle, absorbing and storing water from the soil and releasing it through transpiration.

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16
Q

What does NPP stand for?

A

Net Primary Productivity.

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17
Q

What is ‘Net Primary Productivity’ (NPP)?

A

The amount of biomass or carbon produced by primary producers per unit area and time

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18
Q

Amazonia’s humid equatorial climate creates ideal conditions for what?

(The Rainforest Carbon Cycle)

A

Plant growth.

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19
Q

In the Amazon rainforest, is NPP high or low? What is the average values for carbon and biomass?

(The Rainforest Carbon Cycle)

A

NPP is high.

Carbon: 2500 grams/m2/year.
Biomass: between 400 and 700 tonnes/ha.

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20
Q

How much carbon does a large Amazon rainforest tree typically store?

(The Rainforest Carbon Cycle)

A

180 tonnes C/ha above ground.

40 tonnes C/ha in their roots.

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21
Q

What is the average carbon capacity for soil stores?

(The Rainforest Carbon Cycle)

A

Between 90 and 200 tonnes/ha.

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22
Q

The Amazon rainforest is a major global reservoir of stored carbon. How much does it store each year?

(The Rainforest Carbon Cycle)

A

2.4 billion tonnes a year.

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23
Q

Compared to other forest ecosystems, are carbon exchanges in the Amazon slow?

(The Rainforest Carbon Cycle)

A

No, in comparison they are quicker - with exchanges of carbon between the atmosphere, biosphere and soil all being rapid.

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24
Q

Why are carbon exchanges in the Amazon rainforest much greater than in other forest ecosystems?

(The Rainforest Carbon Cycle)

A

Warm, humid conditions ensure speedy decomposition of dead organic matter and the quick release of CO2.

Rates of carbon fixation through photosynthesis are high.

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25
Q

Does Amazonia’s leached and acidic soils have plentiful carbon and nutrient stores? What does this show?

(The Rainforest Carbon Cycle)

A

No, the stores are limited.

This shows that poor soils support a biome with the highest NPP and biomass of all terrestrial ecosystems, emphasising the speed with which organic matter is broken down, mineralised and recycled.

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26
Q

What 3 factors affect flows and stores of water in the Amazon rainforest and other environments?

(Physical factors and stores and flows of water)

A

Geology, relief, and temperature.

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27
Q

Outline geology’s effect on the flood hydrograph.

(Physical factors and stores and flows of water)

A

Impermeable catchments (e.g. large parts of the Amazon Basin are an ancient shield area comprising impermeable, crystalline rocks) have minimal water storage capacity resulting in rapid run-off.

Permeable and porous rocks such as limestone and sandstone store rainwater and slow run-off.

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28
Q

Outline relief’s effect on the flood hydrograph.

(Physical factors and stores and flows of water)

A

Most of the Amazon Basin comprises extensive lowlands.

In areas of gentle relief, water moves across the surface (overland flow) or horizontally through the soil (throughflow) to streams and rivers.

In the west the Andes create steep catchments with rapid run-off.

Widespread inundation across extensive floodplains (e.g. the Pantanal) occurs annually, storing water for several months and slowing its movement into rivers.

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29
Q

Outline temperature’s effect on the flood hydrograph.

(Physical factors and stores and flows of water)

A

High temperatures annually generate high rates of evapotranspiration.

Convection is strong, leading to high atmospheric humidity, the development of thunderstorm clouds and intense precipitation.

Water is cycled continually between the land surface, forest trees and the atmosphere by evaporation, transpiration and precipitation.

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30
Q

What dominates the biomass of the Amazon basin?

(Physical factors affecting stores and flows of carbon)

A

Forest trees.

These are the principal carbon store.

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31
Q

In total, how many tonnes of carbon is locked up in the Amazon rainforest?

(Physical factors affecting stores and flows of carbon)

A

Approximately 100 billion tonnes.

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32
Q

How much CO2 does the Amazon rainforest absorb each year? How much is released through decomposition?

(Physical factors affecting stores and flows of carbon)

A

2.4 billion tonnes of CO2 a year

1.7 billion tonnes through decomposition.

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33
Q

What percentage of rainforest carbon is stored in the above ground biomass of tree stems, branches, and leaves? What about the remainder?

(Physical factors affecting stores and flows of carbon)

A

60%.

The remainder is below ground, mainly as roots and soil organic matter.

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34
Q

What process connects the rainforest to the atmosphere carbon stores?

(Physical factors affecting stores and flows of carbon)

A

Photosynthesis.

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35
Q

What three things stimulate primary photosynthesis production?

(Physical factors affecting stores and flows of carbon)

A

High temperatures, high rainfall, and intense sunlight.

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36
Q

How much does Amazonia account for (alone) of all NPP in terrestrial ecosystems?

(Physical factors affecting stores and flows of carbon)

A

15-25%.

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37
Q

Leaf litter and other dead organic matter accumulates temporarily at the soil surface and within rainforest soils. What promotes the rapid decomposition of of organic litter? What carries out the decomposition?

(Physical factors affecting stores and flows of carbon)

A

Leaf litter and other dead organic matter accumulates temporarily at the soil surface and within rainforest soils.

High temperatures and humid conditions promote rapid decomposition of organic litter.

This is carried out by bacteria, fungi, and other soil organisms.

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38
Q

What are the products of decomposition within the Amazon rainforest?

(Physical factors affecting stores and flows of carbon)

A

Releases nutrients to the soil for immediate take-up by tree root systems.

Emits CO2 which is returned to the atmosphere.

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39
Q

Outline the geology of the Amazon Basin.

(Physical factors affecting stores and flows of carbon)

A

Dominated by ancient igneous and metamorphic rocks.

Carbonates are largely absent from the mineral composition of these rocks.

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40
Q

State 3 reasons for why deforestation is carried out.

(Human factors affecting stores and flows of water)

A

Crop farming.

Cattle farming.

Road construction.

Settlement.

Mining.

Logging.

Fuel.

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41
Q

What is the average rate of deforestation each year in the Amazon?

(Human factors affecting stores and flows of water)

A

17,500km²/year.

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42
Q

Since 1970, how much of primary Amazon rainforest has been destroyed or degraded?

(Human factors affecting stores and flows of water)

A

1/5.

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43
Q

In what year did deforestation rates fall? Why did they go back up?

(Human factors affecting stores and flows of water)

A

Began to fall from 2009.

They have risen in recent years after the appointment of now former Brazilian president Bolsonaro.

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44
Q

How was deforestation in the Upper Madeira drainage basin affected the water cycle?

(Human factors affecting stores and flows of water)

A

Reduced water storage in forest trees, soils, permeable rock and the atmosphere.

Fewer trees also means less evapotranspiration and less precipitation.​

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45
Q

Between 2000 and 2012, how much of the Bolivian rainforest was cleared for subsistence farming and cattle ranching.

(Human factors affecting stores and flows of water)

A

30,000km².

46
Q

Between 2000 and 2012, 30,000km² of Bolivian rainforest was cleared for subsistence farming and cattle ranching. What did this result in?

(Human factors affecting stores and flows of water)

A

A reduction in water storage and increased surface run-off.

47
Q

Turning rainforest into grassland increases run-off by what factor? What has this led to?

(Deforestation changes the climate at local and regional scales)
(Human factors affecting stores and flows of water)

A

A factor of 27.

This has led to 1/2 of all rainfall going directly to rivers.

48
Q

Future projections suggest a regional rainfall decline of what percentage? What else is projected?

(Deforestation changes the climate at local and regional scales)
(Human factors affecting stores and flows of water)

A

20%.

Forests hundreds of km away will be affected too.​

49
Q

The Amazon water cycle is driven by what? What do they sustain and contribute to?

(Human factors affecting stores and flows of water)

A

The water cycle is driven by forest trees.

These sustain high atmospheric humidity, which contributes to cloud formation and heavy convectional rainfall.

50
Q

Deforestation breaks the water cycle and leads to permanent changes in local and regional climates. What are some of the changes?

(Human factors affecting stores and flows of water)

A

Soil erosion.

Reduction in infiltration capacity.​

51
Q

Increased run-off due to deforestation also significantly increases what?

(Human factors affecting stores and flows of water)

A

The risk of flooding.

52
Q

What happened to the Madeira River in 2014?

(Human factors affecting stores and flows of water)

A

The Madeira River flooded, reaching record level heights of 19.68m above normal at Porto Velho.

Vast areas of the floodplain were inundated.

53
Q

What is the Madeira River?

(Human factors affecting stores and flows of water)

A

The Amazon’s largest tributary.

54
Q

How many people died as a result of inundated floodplains near the Madeira River (2014)?

(Human factors affecting stores and flows of water)

A

60.

55
Q

How many families were evacuated as a result of inundated floodplains near the Madeira River (2014)?

(Human factors affecting stores and flows of water)

A

68,000.

56
Q

What was a secondary effect of the Madeira River floods (2014)?

(Human factors affecting stores and flows of water)

A

There were outbreaks of cholera because of the floods.

57
Q

What was the main driver of most flooding events in 2014?

(Human factors affecting stores and flows of water)

A

Even though torrential rains cause flooding in the Amazon, the main driver of most flooding events is deforestation.​

58
Q

In undisturbed primary rainforest what percentage of all carbon in the ecosystem is stored by trees?

(Human factors affecting stores and flows of carbon)

A

60%.

59
Q

What is the above ground carbon biomass in the Amazon rainforest?

(Human factors affecting stores and flows of carbon)

A

Around 180 tonnes/ha.

60
Q

What is the below ground carbon biomass in the Amazon rainforest?

(Human factors affecting stores and flows of carbon)

A

Around 40 tonnes/ha.

61
Q

What structures in the Amazon’s below ground carbon biomass, store carbon?

(Human factors affecting stores and flows of carbon)

A

Roots and dead organic material.

62
Q

When an area of the Amazon rainforest is cleared for croplands and pasture, what does the carbon biomass drop to? What happens in the cropland is then used for soya cultivation?

(Human factors affecting stores and flows of carbon)

A

16.2 tonnes/ha.

Reduced to 2.7 tonnes/ha for soya cultivation, significantly reducing the stored carbon.​

63
Q

There is also a significant reduction in the inputs of organic material to the soil when forestry is cleared for pasture. What effect does this have?

(Human factors affecting stores and flows of carbon)

A

Area supports fewer decomposers, reducing the flow of carbon from the soil to the atmosphere.

64
Q

What are the principle store of nutrients? Give 3 examples of nutrients stored.

(Human factors affecting stores and flows of carbon)

A

Forest trees.

Calcium, potassium, and magnesium.

65
Q

What is leaching?

(Human factors affecting stores and flows of carbon)

A

When nutrients not taken up by tree roots are quickly washed away by rainwater.

66
Q

If leaching occurs, what may happen to soils? Why?

(Human factors affecting stores and flows of carbon)

A

Soils may be quickly eroded, as they are unprotected by vegetation.

67
Q

Do soils contain many primary nutrients (calcium, potassium, and magnesium)? What restricts soils obtaining them?

(Human factors affecting stores and flows of carbon)

A

Soils contain very little of these essential nutrients, most coming from forest trees.

Deforestation therefore destroys the main nutrient store.

68
Q

The degrading or outright destruction of large areas of Amazon rainforest is an issue of international as well as national concern. Why?

(Strategies to manage tropical rainforests)

A

Deforestation has implications for global climate change.

69
Q

Much much of the Amazon rainforest is Brazil committed to restoring by 2030?

(Strategies to manage tropical rainforests)

A

120,000 km2.

70
Q

How have indigenous people managed to live sustainably in the Amazon rainforest?

(Strategies to manage tropical rainforests)

A

Maintaining the water balance.

Maintaining the carbon cycle.

Maintaining the forest’s biodiversity.

71
Q

How long have indigenous people lived within the Amazon rainforest?

(Strategies to manage tropical rainforests)

A

Thousands of years.

72
Q

How did indigenous Amazonians survive?

(Strategies to manage tropical rainforests)

A

Hunter-gatherers and shifting cultivators.

73
Q

Compare modern day Amazon rainforest use to indigenous use.

(Strategies to manage tropical rainforests)

A

Modern day: Exploitative commercial farming, logging and mining of the past 50 years.

Indigenous people: Pursue a way of life perfectly adapted to the limited resources and fragility of the rainforest.

74
Q

What are the three categories that are being used to sustainably manage the Amazon rainforest?

(Strategies to manage tropical rainforests)

A

Protection through legislation of large expanses of primary forest so far unaffected by commercial developments. (Protection through legislation)

Projects to reforest areas degraded or destroyed by subsistence farming, cattle ranching, logging and mining.
(Reforesting)

Improving agricultural techniques to make permanent cultivation possible.
(Agricultural improvement)

75
Q

Since 1998, what has the Brazilian government done to protect rainforests? Scale?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

Established many forest conservation areas.

These Amazon Regional Protected Areas now cover an area twenty times the size of Belgium.

76
Q

By 2015, what percentage of the Brazilian Amazon comprised national parks, wildlife reserves and indigenous reserves where farming is banned?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

44%.

77
Q

Who was the first indigenous group in Amazonia to join the UN’s REDD scheme? When?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

The Suruí, 2009.

78
Q

What does the REDD scheme stand for?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

The UN’s Reducing Emissions from Deforestation and Degradation scheme.

79
Q

What is the REDD scheme? What does it do?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

Provides payment to the tribe for protecting the rainforest and abandoning logging.

It is a market-based approach involving granting of carbon credits to the Suruí.

80
Q

What are carbon credits?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

Credits that can be purchased by international companies which have exceeded their annual carbon emissions quotas.

81
Q

Who are Natura? In 2013, how many tonnes of carbon credits did Natura buy from the Suruí? How much is this in US currency?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

A large cosmetics TNC.

120,000 tonnes of carbon credits from the Suruí.

This is around US$6.12 million.

82
Q

When was the first carbon credit sale by indigenous people in Amazonia? Who participated?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

2013.

Natura and the Suruí.

83
Q

What type of approach is legislation protection?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

A national approach.

84
Q

What type of approach is the REDD scheme?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

A global legislation approach, (as it’s part of the UN).

85
Q

How can the carbon credit scheme be viewed as a short-term scheme?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

Paying to not cut down trees, instant economic gain instead of deforestation.

86
Q

How can the carbon credit scheme be viewed as a long-term scheme?

(Protection through legislation)
(Strategies to manage tropical rainforests)

A

If tribes continue to cut down trees, then both trees and tribes will become void.

87
Q

Reforestation projects are sponsored by several organisations. State 3 types.

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Local authorities.

NGOs.

Businesses.

88
Q

Has progress been efficient in reforestation schemes?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Progress has been slow.

89
Q

Give an example of a reforestation scheme.

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Parica project in Rondônia in the western Amazon.

90
Q

What does the Parica project aim to do?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Develop a 1000 km2 commercial timber plantation on government-owned, deforested land.

91
Q

Outline the Parica projects plan.

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Plant 20 million fast-growing, tropical hardwood seedlings on 4000 smallholdings, to mature over a period of 25 years.

92
Q

How does the Parica project help smaller organisations to engage in the reforesting scheme?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Financial assistance is given to smallholders for land preparation, planting and the maintenance of plots.

Tree nurseries provide them with seedlings.

Timber is exported along the Amazon and its tributaries through Manaus or Port Velho.

93
Q

What is a disadvantage of the Parica project?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

It is a monoculture.

It cannot replicate the biodiversity of the primary rainforest.

94
Q

What is a monoculture? Why are they bad?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

The practice of growing one crop species in a field at a time

They rely heavily on chemicals which leads to pollution.
Reduces organic matter in soil.
Reduces soil biodiversity.

95
Q

What are 3 advantages of the Parica project.

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Taps carbon in the trees and soil.

Reduces CO2 emissions from deforestation.

Re-establishes water and carbon cycles.

Reduces run-off and the loss of plant nutrients and carbon from the soil.

It is sustainable.

96
Q

The Parica project takes place in Rondônia. What other scheme is taking place?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

A scheme where indigenous Suruí people participate and aim to protect primary rainforest on tribal lands from further illegal logging, and reforest areas degraded by deforestation in the past 40 years.

97
Q

How do the Suruí contribute to reforesting (through the scheme in Rondônia)?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Plant seedlings bred in local nurseries in deforested areas around their villages.

98
Q

What plant species are planted by the Suruí (through the scheme in Rondônia)? Why?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Native species.

This provides them with timber for construction, food crops and, through logging, a sustainable source of income.

99
Q

For everyone 50 trees cut down in the Amazon, how many are sold (economic viability)?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

1.

100
Q

What are 2 advantages of protection rainforests through reforesting projects?

(Protection through reforesting projects)
(Strategies to manage tropical rainforests)

A

Better than leaving deforested land.

Forest trees are important to water and carbon cycles.

Storing carbon and regulating the water cycle in some areas.

Damage is already done - aims to restore what previously existed.

101
Q

What has been the main cause of deforestation in Amazonia?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

Farming.

102
Q

Deforestation creates land for farming. What was a resultant issue of this? What happened?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

Low fertility of soils meant that permanent cultivation proved unsustainable.

After a few years, many smallholders abandoned their plots which were then converted to low quality grassland.

103
Q

How can soil fertility be maintained?

(Diversification)
(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

Rotational cropping, combining livestock, and arable operations.

104
Q

Integrating crops and livestock could increase ranching productivity by how much? What would it do to deforestation?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

A fivefold increase in ranching productivity

Slow rates of deforestation.

105
Q

What did European explorers observed about the Amazon rainforest in the 16th century?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

It supported high population densities, and many large urban centres.

106
Q

European explorers observed that the Amazon rainforest, as late as the sixteenth century, supported high population densities, and many large urban centres. What does this contradict?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

The view that natural resources for farming in the region are too poor to support settled, permanent cultivation.

107
Q

What is the supposed explanation for how the Amazon rainforest can support such high population densities?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

Human-engineered soils: so-called dark soils.

108
Q

What are dark soils made from?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

Inputs of charcoal, waste, and human manure.

109
Q

How is it that dark soils can retain fertility on long-term?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

The charcoal in these soils attracts micro-organisms and fungi.

110
Q

Scientists are currently investigating dark soils. What would be possible if they can be successfully recreated?

(Protection through improved agricultural techniques)
(Strategies to manage tropical rainforests)

A

They would allow intensive and permanent cultivation which would drastically reduce deforestation and carbon emissions.

Earth's Life Support Systems (9 decks)

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