2.A - the carbon and water cycle in the Amazon basin Flashcards

Question

where is moisture loss from?

Answer 1

moisture loss in transpiration from the soil via the roots

Answer 2

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

Answer 3

- impermeable catchments, e.g. large parts of the Amazon basin are an ancient shiled area, comprising impermeable crystalline rocks that have minimal water storage capacity - permeable and porous rocks such as limestone and sandstone store water

Answer 4

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

Answer 5

- high temps throughout the year generate high rates of evapotranspiration. - convection is strong, leading to high atmospheric humidity, the development of thunderstorm clouds and intense precipitation

Answer 6

- impermeable rocks have minimal water storage capacity, resulting in **rapid run off** - permeable and porous rocks store rainwater and **slow run off**

Answer 7

- most of the Amazon basin comprises extensive lowland - 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 w/ **rapid runoff**

Answer 8

GEOLOGY - if the rock type is impermeable, it is always going to lead to surface run off and increased flood risk

Answer 9

- shows pattern of precipitation and how flow of river responds to rainfall (the input)

Answer 10

- naturally, in the Amazon (primary rainforest), flood risk is low and has a very large lag time - however, in deforested areas, there is high flood risk due to thin soils and impermeable rocks. - it reduces lag time, much steeper rising limb and higher peak discharge

Answer 11

- there has to be at least 2000mm of rain annually - but mostly 3000-4000mm

Answer 12

- leaves in the canopy interrupt the rain by intercepting and slowing flow of water to the ground - the water continues its journey downwards by throughfall and stem flow

Answer 13

- the high levels of rainfall affect the soil by dissolving/leaching the nutrients - this means that the layer of organic/carbon content is quite thin - leaching leaves behind insoluble compounds = soil is reddish brown

Answer 14

- leaching leaves behind insoluble compounds = soil is reddish brown

Answer 15

- removing the canopy, less rain is intercepted - this means it falls on the forest floor, washing away the organic layer and increasing surface run off

Answer 16

- as roads are built more bare soil is revealed, meaning that ↑ run off and soil erosion even more - this causes water channels to get silted up, which can increase risk of flooding

Answer 17

- palm oil relies on there being no other plants, exposing more bare soil, increasing the amount of surface run off and leaching. however, it affects rainfall patterns - in a primary forest, some of the water is evapotranspired, which forms water vapour, clouds and rain. - reducing the primary forest means there’s less canopy cover, meaning the amount of evapotranspiration is reduced, therefore there are less clouds and therefore less rainfall. - this reduction in rainfall will reduce the rate of forest growth, thus acting as a positive feedback loop

Answer 18

- 1/5 of the primary forest has been degraded or destroyed since 1970

Answer 19

- devastating floods occured on the Madeira River, the largest tributary of the Amazon river

Answer 20

- both heavy rainfall and deforestation have been recognised as contributing causes - however, there is also speculation that the Santo Antonio and Jirau Dams were also responsible - the 2 new dams located in the Brazilian state of Rondonia could have caused the extensive flooding see in parts of Bolivia and more recently Rondonia in Brazil - critics fear that the dams now prevent the natural flow of rivers and retain floodwaters for a longer time and in larger volumes

Answer 21

- at Porto Velho the river reached record levels of **19m** above normal - vast expanses of flood plain were inundated - **60** people died - **68,000** families were evacuated and there were outbreaks of cholera and leptospirosis

Answer 22

- converting rainforest to grassland ↑ run off by a factor of 27 - (**50%** of all rain falling on grassland goes directly into rivers)

Answer 23

- tends to be high w/ frequent and intense rainstorms - hot temps at the equator facilitate high rates of evapotranspiration from oceans, which is blown on land, condenses and cools, leading to convectional rainfall events

Answer 24

- a portion of the rainfall is intercepted by trees and flora, as raindrops falling towards the ground are caught on their leaves - much of this intercepted water is evaporated directly back into the atmosphere meaning it never reaches the underlying land

Answer 25

- infiltration should occur quickly because the trees provide leaf litter which maintains soil humus - the soil humus allows water to soak into it so it promotes infiltration

Answer 26

- much of water in soil is taken up by vegetation - this water is moved up through the vegetation by the xylem vessels and is lost back to the atmosphere as water vapour through the stomata via the process of transpiration

Answer 27

- water that was evaporated from leaves following interception, transpired by vegetation or evaporated directly from the soil reenters the atmosphere as water vapour - helps to maintain humid conditions in tropical forests and when the moisture in the air condenses it will fall again as rain and is recycled.

Answer 28

- atmospheric aridity leads to a decrease in rainfall as there is less water vapour in the air to condense into raindrops. - less water will infiltrate into soil = less moisture available for plants to take up through their roots - this can lead to water stress and vegetation die back - can be spatially variable

Answer 29

- natural recycling of water = disrupted - when rain falls in areas where forest vegetation has been removed or replaced w/ crops, much less of the water is intercepted as there are fewer leaves, with a smaller combined SA to catch the raindrops = more reaches ground

Answer 30

- infiltration in deforested areas will be reduced because soil and hummus become diminished - the thin soils are washed away once they have lost the protection of the canopy

Answer 31

- rates of evapotranspiration from crops will be much lower than forests - crops = less dense, fewer plants to transpire and roots are shallower so theyre unable to access water deeper in soil - therefore instead of reentering the atmosphere, water will move towards the river

Answer 32

- the ↓ in water being evaporated from leaves after interception, coupled with a decrease in transpiration, means that there is much less water vapour being returned to the atmosphere after a rainfall event = ↓ in humidity - air masses moving inland become arid as they pass over unvegetated areas

Answer 33

- decomposition is an active process in tropical climates - decomposers such as fungi and bacteria thrive in the warm and wet conditions - this process releases carbon dioxide back to the atmosphere

Answer 34

- ideal for plant growth - promotes the process of photosynthesis, which absorbs huge quantities of CO2 from the atmosphere

Answer 35

- wood is 50% carbon, so rainforest plants and trees are a huge carbon store - they are important "carbon sinks" in mitigating the effects of global warming

Answer 36

- forest trees dominate the biomass of the amazon and are the PRINCIPAL CARBON STORE - large forest trees typically store around **180 tonnes/ha** - absorbing around **2.4 billion tonnes** of CO2 a yr and releasing **1.7 billion tonnes** through decompostion, the rainforest is a carbon sink of global importance - **60%** of rainforest carbon is stored in the above ground biomass of tree stems, branches and leaves

Answer 37

- photosynthesis connects the rainforest to the atmosphere carbon stores - high temps, high rainfall and intense sunlight stimulate primary production - Amazonia alone accounts for 15-25% of all NPP in terrestrial ecosystems

Answer 38

- when trees are felled and left, they decompose - leaf litter and other organic matter accumulates temporarily at the soil surface and within rainforests - high temps and humid conditions promotes decomposition of organic litter by bacteria, fungi and other soil organisms - decomposition releases nutrients to the soil for immediate take up by root systems, and emits CO2 which is returned to the atmosphere

Answer 39

- the geology of the Amazon basin is dominated by ancient igneous and metamorphic rocks - carbonates are largely absent from the mineral composition of these rocks - however, in the western parts of the basin, close to the Andes, outcrops of limestone occur. - in the context of the slow carbon cycle they are significant regional carbon stores

Answer 40

80% of deforestation in Amazon is cut down for grazing

Answer 41

NPP is high avg. 2500 grams/m2/yr

Answer 42

largest terrestrian sinks of CO2

Answer 43

not affected by human activity

Answer 44

up to 3000

Answer 45

- only cutting down the largest tree - 50%

Answer 46

- a carbon SOURCE, not sink - dead trees and stumps are broken down by decomposers, releasing the carbon

Answer 47

- one that regrows after initial deforestation - they expected to find that these will act as carbon sinks as plants/trees are growing - the impacts of logging don’t disappear that quickly

Answer 48

palm oil, thousands of hectares

Answer 49

- in palm oil plantations, there is only about **30 tonnes** of carbon per hectare - **10%** of primary rainforest - palm oil plantations fix less than 50% the carbon of a primary TRF (less dense canopy)

Answer 50

- by 2025, there will be an additional **9 mill hectares** of palm oil plantations, and for every hectare that is converted, **100 tonnes** of carbon is released

Answer 51

- the above ground carbon biomass in the rainforest is approx. 180 tonnes/ha (can be up to 400)

Answer 52

- in the primary rainforest (unaffected), the biomass of trees represents about 60% of all carbon in the ecosystem - most of the remaining carbon is found in the soil as roots and dead organic material - crops and pasture contain only a small amount of carbon compared to forest trees - e.g. the biomass of grasslands in areas of former rainforest is **16.2 tonnes/ha** and for soya cultivation it is just **2.7 tonnes/ha**

Answer 53

- soils, depleted of carbon and exposed to strong sunlight, support fewer decomposer organisms, thus decrease the flow of carbon from the soil to the atmosphere - in rainforests, the principal store of plant nutrients such as calcium, potassium and magnesium is forest trees - rainforest soils contain only a small reservoir of essential nutrients and the forest is only sustained by a rapid nutrient cycle - deforestation destroys the main nutrient store - the forest trees - and removes the most nutrients from the ecosystem - nutrients no longer taken up by root systems of trees are washed out of soils by rainwater; and soils, without the protective cover of trees, are quickly eroded by run-off

Answer 54

- cattle ranching accounts for 80% of current deforestation throughout the Amazon - alone, the deforestation caused by cattle ranching is responsible for the release of **340 million tons** of carbon to the atmosphere every year, equivalent to 3.4% of current global emissions. - soy developers then capitalise on the cattle ranchers and take over the land, pushing cattle ranching (and deforestation) towards new pioneer areas (feedback loop)

Answer 55

- water vapour is also considered a greenhouse gas - deforestation has decreased global vapour flows from land by 4%. - even this slight change can disrupt natural weather patterns and change current climate

Answer 56

- bulldozers - later the timber will be burned which releases stored carbon.

Answer 57

- increased precipitation = ideal growing conditions = increased photosynthesis and carbon storage

Answer 58

- vegetation is a store of water = as it grows it stores more - account for the exchange of carbon between soils/plants/atmosphere through photosynthesis (only occurs in the day)/transpiration/respiration (releases carbon more due to day and night - intercept water to decrease run off

Answer 59

- alters levels of photosynthesis and less nutrients in soil = decreased chance of regrowing - less decomposers - ↓ carbon stores = ↓ water stores - ↓ evaporation = ↓ precipitation = ↓ run off and ↑ erosion of soils by water = ↓ fertility of soils and also ↓ photosynthesis = ↓ carbon stored

Answer 60

- shifting cultivation is a traditional method of cultivation in tropical rainforests which involves the rotation of land rather than just the rotation of crops - it involves producing just enough food for survival and then moving onto new land

Answer 61

- small areas of forest are cleared to provide land for farming - the soil in this area stays fertile for around 10 yrs before farmers have to move again - this means a new area of forest needs to be cleared where soil is more fertile - after another several years, farmers will move again and this process keeps repeating - by the time theyre moving back to the first plot of land it will be fertile again and after 10 yrs they can move again

Answer 62

- forest is cleared for crops until the soil is exhausted of nutrients or the site is overtaken by weeds and then moving on to clear more forest - it therefore increases deforestation rates as new areas of land are cleared after several years while the previous plot is recovering - however as a replacement for mass clearing of trees, it is better

Answer 63

- it is more sustainable for the environment than other forms of deforestation as areas have time to regrow - the soil regains its fertility when farmers move on to new land - it is the traditional method that has been used by indigenous people for thousands of years - it is better for the environment as plants can regrow whilst farmers are elsewhere

Answer 64

- trees are cut down to make space for farming - could be multiple areas of land cut down at at time - it is more efficient for farmers to clear larger areas at a time - not utilised as much because people want economic growtha and dont care much about the environment - not great for economic progess - takes more time and planning

Answer 65

- shifting cultivation as an alternative method of deforestation creates less drastic change to the carbon cycle - amount of photosynthesis occurring in rainforest decreases less than the usual deforestation technique used - less carbon stores removed at one time - less carbon released into the atmosphere (only doing a small amount at a time)

Answer 66

- like the impact on carbon stores, shifting cultivaion has a less significant impact on the water cycle - when trees are removed, the amount of precipitation decreases and the surface run off increases - however this is *less significant* due to the fact only a few acres are cut down at a time the area can still remain quite sheltered

Answer 67

**POSITIVES** - it provides an alternative method of living in the rainforest - mitigates problem instead of adapting (prevent problem from occuring in the first place - provides land for farming/living - income and growth - only affects a small area initially

Answer 68

- doesnt replant any trees - soil becomes infertile for periods of time - loss of habitat - doesnt solve problem of deforestation

Answer 69

- shifting cultivation is effective as a small scale management strategy for living more sustainably in the rainforest - however it is less suitable for commercial farmers as only small areas are cleared at a time.

Answer 70

- afforestation involves planting trees in areas that havent recently had any tree cover, in order to create a forest - the type of land planted could include areas that have turned into desert through *desertification*, or places that have long been used for agriculture, or industrial areas - acts as a method to reduce atmospheric CO2 - the forests created through afforestation also provide a habitat to local wildlife, create wind breaks and support soil hea;th - **it reverses deforestation rates** and is the only strategy to do so

Answer 71

- more flows of photosynthesis - improves topsoil, nitrogen is fixed at higher rates, which has also been shown to neutralize soil pH (reducing acidity in acid soils and alkaliity in alkaline soils) - improvement in soil fertility and promoting ecosystem productivity - allows for more recycling of water via transpiration and evaporation from leaves - reduces run off

Answer 72

- more carbon is able to be stored so it ultimately **mitigates climate change** - afforestation can reverse biodiverstity losses and provide carbon sinks, which are natural environments that are able to absorb carbon dioxide from the atmosphere - increases carbon storage in soils and trees overall - interception decreases levels of surface run-off - increases soil fertility and amount of photosynthesis so theres less soil erosion and more nutrients for decomposition

Answer 73

- communities and governments choose to invest in afforestation projects, for example: - The Peugot-ONF Forest Carbon Sink project in Mato Grosso state of the Brazilian Amazon, has achieved significant ecological restoration and carbon sequestration results - the reforestation of the 2000 hectares of degraded cattle pasture has reached a level of biodiversoty similar to native forest and introduced a wide range of Amazonian species - a total of 394,400 metric tonnes of CO2 has already been sequestered by the project - the eqivalent of 85,000 cars taken off the road for a year.

Answer 74

- afforestation depends on the quality of the soil - if a hard, impenetrable surface to the soil has formed, it needs to be broken up and the soil aerated - trees also have to suit the local environment. the most significant risk is the use of non-local tree species - these trees may be fast growers that will draw down carbon, but may use more water than the area has available - you have to consider prevailing winds and the direction of sunlight in different seasons - it takes around 120 yrs for topsoil biomass and composition of species to recover. - not as good for wildlife as primary forests

Answer 75

- improves soil health and quality - reverse land degredation - halts land desertification - provides clean water through an intensified water cycle - improve water levels of the groundwater, thus reducing flooding - creates income generation

Answer 76

- overall, an effective way of controlling deforestation rates and reducing greenhouse gas emissions in the SHORT TERM - however, trees take time to grow and reach optimal photosynthesis levels - additionally, it heavily relies on funding (NGOs, Govts, global firms) - it is hard to implement on a large scale with only some areas being replanted - in the long run it would have been more beneficial to have stricter and upheld rules on deforestation - although afforestation is considered to be one of the most "natural" and simple ways to reduce carbon dioxide emissions - cost

Answer 77

there are 2 main diversification of agriculture methods used: 1. Dark soils 2. agroforestry

Answer 78

- the idea explores the use of human engineered soils - these so called dark soil are made from inputs of charcoal, waste and human manure - scientists are currently investigating these new soils, if they can be successfully recreated they would allow intensive and permanent cultivatrion which would drastically reduce deforestation and carbon emissions

Answer 79

- the charcoal in the new soils attracts micro-organisms and fungo and allows the soil to retain its fertility long term - this means that one area can be used to grow crops for multiple seasons and therefore limits the amount of open land farmers need to grow crops and decreases deforestation.

Answer 80

- agroforestry is the deliberate culture of plant species interacting ecologically or economically with seasonal cultivations and/or animal breeding - originally people's lifestyle in the Ecudorian Amazon was nomadic. their lifestyle depended on hunting and food gathering but they were also practicing *slash-and-burn* agriculture - however in recent years when farmers began to settle they have turned to agroforestry

Answer 81

- agroforestry mimicks nature, using a "polyculture" of trees to regenerate land and restore biodiversity whilst also producing crops. - ultimately, it creates a healthy ecosystem and spares farmers the choice between nature and livelihoods - overall it is a sustainable method of farming which artificially replicates the rainforest and therefore decreases deforestation as it provides a way for farmers to use land without having to clear areas using slash and burn techniques

Answer 82

- using agroforestry instead of slash and burn will mean less areas of open forest and therefore increase interception - this will in turn increase lag time and decrease peak flow, reducing the flood risk in the local area - additionally, agroforestry will lead to increase rainfall being recyled and put back into the atmosphere by transpiration

Answer 83

- dark soils may have a larger moisture storing capacity and therefore also decrease surface runoff

Answer 84

- the use of agroforestry and dark soils means the overall amount of deforestation that has to occur for farmers to make a living out of agriculture decreases - therefore, this decreases the amount of CO2 released into the atmospher when areas of the rainforest are felled to make clearing - additionally the volume of CO2 absorbed by photosynthesis will increase, as will the volume of oxygen produced.

Answer 85

- these could be very successful in the long term as they would severly decrease the volume of trees that could be felled for farming - however, it could be argued that many farmers may just continue to farm using current methods due to the difficulty implementing dark soils and agroforestry - furthermore, agroforestry could be considered less profitable and therefore may not be as effective in attracting people to operate in this way - changing land ownership is a barrier = farmers have to stay on a specific patch of land for it to work

Answer 86

- the UN's "Reducing Emissions from Deforestation and Degredation" (REDD) scheme provides payment to the Surui indigenous group for protecting the rainforest and abandoning loggin - it is a market-based approach involving the granting of carbon credits to the Surui - these credits can be purchased by international companies who have exceeded their annual carbon emission quotas - for example in 2013 Natura, a large TNC, purchased 120,000 tonnes of carbon credits from the Surui - this was the first carbon credit sale by indigenous people in Amazonia

Answer 87

- it dramatically reduced deforestation within the territory during its first five years of operation (2009-2014), but was suspended in 2018 after the discovery of large gold deposits in the territory sparked a surge in deforestation (suggets its long term impermanence) - a large limitation of this scheme is "leakage": a reduction in carbon emissions in one area that results in increased emissions in another - a classic example is where curbing clearfelling in one region of forest drives farmers to clearfell in another

Answer 88

- REDD schemes prevent deforestation in the Amazon, so therefore limit the impacts felt by the water cycle, such as increased run off and flood risk, and decreased interception and transpiration (leading to droughts) - this means the water cycle is ultimately unaffected as the forest is left untouched - therefore, habitats remain stable, and social impacts from extreme weather/natural hazards are prevented - however, the potential impermanence and difficulty of monitoring this strategy may mean that deforestation will occur in these areas in the future, so the water cycle will be affected.

Answer 89

- before being suspended, the project generated 300,000 carbon offsets certified under the Verified Carbon Standard (VCS) - this is equal to removing 64,000 cars from the road for a year - this helps to meet the global imperative to sequester carbon from the atmosphere, where it acts as a greenhouse gas, enhancing the greenhouse ffect and contributing to global climate change - reducing deforestation means primary forest remains: storing 400 tonnes of carbon per hectare - there is less combustion and felling of forest so stored carbon is not released and the trees can continure photosynthesising and contributing to the Amazon's carbon sink

Answer 90

- the surui used proceeds from offset sales to finance 6 sustainable community development initiatives that generate income and support traditional practices, such as the harvesting of medicinal plants. - this enables long term socio-economic development which is not reliant on deforestation in the area by putting even more value on the land: but this is on a local scale - large scale in terms of carbon offsetting; it removes vast amounts of carbon from the atmosphere by sequestration - relatively cost-effective: offsets cost less that $50 per tonne of CO2 (carbon capture costs $250-650)

Answer 91

- carbon calculations may be inaccurate and they have a high degree of uncertainty - difficult to monitor accurately and reliably - you cant tell if it would have been left as primary forest anyway (no extra carbon is being sequestered) - LEAKAGE - deforestation will increase elsewhere - imbalance of the water cycle can cause flooding downstream and felling elsewhere will affect the Amazon's ability to sequester the maximum amount of carbon - permanence: the long term viability of reduced emissions from a REDD project is heavily dependent on the forested area's vulnerability to deforestation and/or degredation