ELSS AMAZON RAINFOREST STUDY

• what is the climate in the tropical rainforest?

  no distinct seasons; annual temperature range is low; incoming solar radiation is relatively concentrated and temperatures are high; intense heat = convectional rainfall; presence of clouds mean temperatures do not reach extremes associated with desserts and diurnal (daily) temperature range is small
• what is the annual temperature range in Manus, Brazil?

  high of 28 degrees; low of 27 degrees; range of 1 degree
• what is the input flow of the tropical rainforest?

  precipitation - high annual rainfall (>2000mm) distributed evenly annually; around 50% of rainfall is evapotranspired
• what is the main output flow of the tropical rainforest?

  evapotranspiration - rapid due to high temperatures, abundant moisture and dense vegetation; feedback loops helps to maintain precipitation levels; most evaporation is intercepted rainfall; moisture lost in transpiration originates from soil
• what is the other output flow of the tropical rainforest?

  run-off - rapid run-off from high rainfall totals and intense rainfall events - seasonal distributions of rainfall may be reflected
• what is the 3 stores of the tropical rainforest?

  atmosphere - absolute humidity is high which allows high moisture stores + relative humidity is also high; vegetation - trees absorb water from the soil, stores it and then releases to atmosphere during transpiration; soil and rock - significant amounts of water stored in soils and aquifers
• how does temperature affect the water cycle in the tropical rainforest?

  high temperatures generate high rates of evapotranspiration; convection results in high humidity which causes cumulonimbus clouds and intense precipitation; evaporation, transpiration and precipitation continue to cycle water between the land, vegetation and atmosphere
• how does the geology affect that water cycle of the tropical rainforest?

  impermeable crystalline rocks in Brazilian shield have minimum water storage capacity so run-off is rapid; regions with permeable and porous rocks and sandstone store water and slow run-off
• what is the impact of relief on the water cycle in the tropical rainforest?

  andes create steep catchments of rapid run-off; extensive lowlands and gentle relief are associated with throughflow and overland flow to rivers and streams; flooding of extensive floodplains occurs every year, storing water for several months and slowing its movements to rivers
• what are the rates of deforestation?

  average 17,500 km2 per year from 1997-2013; 20% pimary forest destroyed or degraded; rates of deforestation in the brazilian amazon decreased after 2004 but is starting to increase again since 2018
• what is the deforestation and flooding - Madeira river basin?

  2000-2012: 30,000 km2 of Bolivian Raines was cleared for subsistence farming and cattle ranching; april 2014: madeira river reached record levels (19.68m above normal); 60 people died; 68,000 families were evacuated; outbreaks of cholera
• how does deforestation affect the water cycle?

  deforestation reduced water storage in vegetation, soils and rocks; reduced evapotranspiration means less precipitation; converting rainforest to grassland increases run off by factor of 27 and soil erosion by 10.8; as run off increases so does the flood risk; estimates suggest that rainfall through the amazons by decline by 20% as forest dries out and and grasslands replace trees
• how does deforestation affect the carbon cycle?

  heat is catalyst for reactions and water is plentiful = high photosynthesis which combined with high biomass (400-700 tonnes per hectare) = high rates of net primary productivity (rate at which plants accumulate energy in form of organic matter); large forest trees store 180 tonnes of carbon per hectare above ground and 64 tonnes in roots
• what is Gersmeh


  it is a diagram that shows the differences in nutrient flow and storage between different types of ecosystems

  
• how does the climate (temperature and precipitation) effect the carbon cycle in the tropical rainforest?

  high temperatures and precipitation and intense sunlight stimulate photosynthesis; amazonia accounts for 15-25% of all NPP in terrestial ecosystems; el nino results in droughts, forest fires and reduced NPP
• how does the vegetation effect the carbon cycle in the tropical rainforest?

  trees dominate biomass and are main carbon stores; 100 billion tonnes of carbon is stored in Amazon rainforest; forest absorbs 2.4 billion tonnes of CO2 annually and releases 1.7 billion tonnes due to decomposition; 60% of rainforest carbon is storied in above ground biomass
• how does the soil effect the carbon cycle in the tropical rainforest?

  leaf litter and other organic matter accumulates temporarily within rainforest soils; high temperatures and humid conditions promote rapid decomposition by bacteria and fungi; decomposition releases nutrients to soil for immediate up take by plants and emits CO2 which is returned to atmosphere
• how does the geology effect the carbon cycle in the tropical rainforest?

  carbonates are absent from the indigenous and metamorphic rocks that dominate amazon basin; west of basin limestone outcrops store and release CO2 in slow carbon cycle
• what are the human factors affecting the carbon cycle in the tropical rainforest?

  deforestation exhausts the carbon biomass stores; there is 16.2 tonnes per hectare of carbon in grasslands and 2.7 tonnes in soya cultivation; deforestation also reduced input of organic matter to the soil; soil support fewer decomposers which reduces the flow of carbon from the soil to the atmosphere; without tree cover soils are quickly eroded by run-off
• what is the strategies of managing the rainforest?

  brazil committed to restoring 120,000 km2 of rainforest by 2030; indigenous people lived sustainably in rainforest through hunting and shifting cultivation; protection through legislation is used such as the 1998 law which created amazon regional protected areas; reforesting; improving agriculture to allow permanent cultivation; dark soils; joining UNREDD; planting seedlings in local nurseries; role of indigenous people
• what was the impact of reforestation in sustaining the tropical rainforest?

  sponsored by local authorities and NGOs; parica project in Bondonia which is west amazon aimed to develop 1000 km2 of commercial timber plantation on government owned land and 20 million fast growing hardwood seedlings on 4000 small holdings will mature over 25 years