Water Cycle Case Studies Flashcards
Amazon
Location of the Amazon
-Located in South America, contains over 300 billion trees. It occupies 68% of Brazil, and smaller parts of Peru, Bolivia, Colombia.
-Covers a total of 8.2 million KM2
-300 billion trees and 15,000 store 1/5th of all the carbon in the planet’s biomass.
The Amazons link to the carbon cycle
-300 billion trees and 150bn tones stored there
- 1/5th of all the carbon in the planet’s biomass.
-Plants conduct photosynthesis, releasing oxygen and locking in carbon. Rainforest is known as ‘the lungs of the earth’.
•Stores 20% of all biomass stored carbon on the planet
•Deforestation leads to soils being unconsolidated and therefore soil erosion. This removes the soil stored Carbon and can wash it into the water systems.
•Age of many plants in the rainforest means they are long-term carbon stores
•Regulates global atmospheric Carbon levels
•11% of forest has been deforested releasing carbon
Amazon links to the water cycle.
•Over 3000mm of rain and temp average of 28 oC causes humid conditions.
•75% of this total rainfall is intercepted by the trees and then to the ground through stem flow.
•25% of all the rain evaporates or is returned to the atmosphere via transpiration of plants
•The other 50% is infiltrated through the soil or flows overland into nearby channels
•Deforestation may cause increases in surface runoff, this may lead to greater levels of flooding.
•Discharges 175 000 cumecs of freshwater into Atlantic each second.
•Moisture released into the atmosphere by evapotranspiration in the Amazon has impacts on rainfall in he USA, Europe and SE Asia.
•50-80% of the water within the Amazon is recycled within the ecosystem rather than flowing straight back out of it. The cycle is fast and complex.
•Amazon river
What are the impacts on water cycle in the Amazon: rainfall
-particles resulting from burning of trees increases the density of airborne aerosols around which water vapor condenses. As a result, smaller droplets occur in the clouds which are too small to precipitate, resulting in less local rainfall.
-Forests emit salts and organic fibres along with water when they transpire. These act as condensation nuclei and assist in cloud and rain production. Their loss inhibits the formation of cloud and therefore rainfall.
-Any moisture that does evaporate from deforested areas forms shallow cumulous clouds which do not produce rain
What are the impacts on water cycle in the Amazon: what happens to evapotranspiration with more deforestation
-As evapotranspiration is reduced the atmosphere becomes less humid.
-Transpiration will rapidly decrease.
-With less trees, most rainfall will go straight to the floor encouraging surface flow as soils become dry and baked as it becomes more exposed to the sun.
-Reduced evapotranspiration from cleared areas mean the air is less moist, resulting in a reduction in cloud cover.
-The removal of trees through slash and burn facilitates sudden evaporation of water that was previously retained in the forest canopy.
Links to environmental change and human activity
•the Amazon rainforest has lost approximately 17% of its primary rainforest in the last 50 years. 80% is due to cattle ranching.
•Parts of the Amazon basin experienced drought in 2005 and 2010. The 2010 event lowered the Río Negro upstream from Manaus, isolating local people who depended on the river for transport. Forest fires often occur as a result of drought, releasing the large stores of carbon in the biomass.
•Deforestation alters transpiration and albedo levels, which will lead to reduced precipitation because there is a lower level of atmospheric humidity. This impact is felt locally and thousands of KMs away.
•Hydroelectric power generation – large hydroelectric dams have been constructed on rivers such as the Rio Tocantins and have flooded large areas of rainforest.
•2080 most species won’t be able to live in Amazon due to increased temperatures
How is the change of carbon cycle impacting the rainforest
-temperature of rainforests increased on average by 0.26 degrees every 10 years since the mid 1970s.
-By 2050, it is estimated that temperatures in the Amazon will increase by 2-3 degrees
-3.6million hectares of forest was lost per year between 2000 and 2010. Although most of this was done deliberately, a significant amount has been as result of climate change.
Vegetation change:
Species are specifically adapted to the conditions of the rainforest therefore their tolerance to temperature, seasonality and other climatic changes are limited.
-A 2009 study concluded that a 2degrees temperature rise above pre-industrial levels would result in 20-40% of the Amazon trees dying within 100 years.
-A 3degree rise would result in 75% of the forest destroyed, mainly through drought.
Impacts on soil
Amazonian soils contain 4-9kg of carbon in the upper 50cm of the soil layer compared to the 1km m2 that is contained in soils of pastureland.
-When forests are cleared and burnt, 30-60% is lost to the atmosphere; unburnt vegetation decays and is lost within 10 years. The soil fungi and bacteria that used to recycle the dead vegetation dies off.
Climate change Impacts on rivers
-Destroy water supply which fulfils the needs of Amazonian people
Warming water temperatures may:
-Kill of dependent species
-Change the biodiversity of the river system by introducing new specifies and killing others
Reduce water-dissolved oxygen concentrations, which could destroy eggs and larvae, which rely on dissolved oxygen for survival.
Mitigation:
National and international agreements the TARAPOTO process:
- Began in 1995
-Forest policy makers from 8 member countries identified 12 criteria to help manage the forest sustainably at management, national and global level - National level priorities included:
•Investment in research, education and technology transfer
•Existence of policies and a legal framework for land-use planning through ecological and economic zoning
-Management level included:
•Proportion of environmental protection areas as against permanent production areas
Mitigation: Amazon Cooperation Treaty Organization (ACTO)
• Aimed at promoting sustainable development
• 8 member countries
• Reverse the loss of forest cover worldwide through sustainable forest management, including protection, restoration, afforestation and reforestation, and increase efforts to prevent forest degradationMonitor and prevent illegal logging
Protected areas at the regional levels through conservation corridors going though more than one country
-Brazil aims to plant 73m trees
-80,000 trees have been planted already
Mitigation: local scale and Paris agreement
The creation of national parks and forest reserves:
-Jau National Park covers an area of over 5.6 million acres
-Para rainforest reserve: expanse of 15 million hectares and links to existing reserves to form a vast conservation corridor in the northern Amazon
Agroforestry:
-The combination of planted trees with annual crops, has many environmental and social advantages over predominant land uses in Amazonia, such as cattle pasture.
-Provided that forest is not cut to make way for the agroforestry, trees in agroforestry systems will hold more carbon than would the vegetation otherwise occupying the site.
Reforestation:
- 73 million, to be exact. And that is precisely the number of trees that a nonprofit group called Conservation International hopes to plant across areas of the Amazon rainforest that have been devastated by deforestation in the past.
2010 Paris agreement:
-aims to reduce temperatures to below industrial levels. Net zero by 2050
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