amazon rainforest

• largest tropical rainforest
• how many plant species

  1 million
• why is amazon so wet

  evaporation over atlantic ocean, wet air blown to amazon - contributes to high rainfall
• why so much precipitation

  warm temps = evaporation
• interception

  dense canopy = high interception, less water than expected flows into rivers - and slower
• water cycle affect on species

  adapted to high humidity and frequent rainfall
• carbon sink - carbon stored in vegetation and soil
• amount of biomass is increasing

  more co2 = increased productivity (more photosyntheis)
• carbon sequestration


  more biomass = more carbon stored
• carbon increase effect on trees

  grow quick, die young (can't rely on sink in future)
• human activities impacting cycles

  deforestation, climate change, farming
• deforestation impact on water cycle - interception

  no tree canopy for interception, more water to ground, saturated soil, increased surface runoff = increased flood risk.
• deforestation impact on water cycle - evapotranspiration

  reduced evapotranspiration, so less water vapour in atmosphere, fewer clouds form, rainfall reduced = drought risk
• deforestation effect on carbon cycle - no roots

  no roots to hold soil together, heavy rain washes away nutrient rich top layer = carbon stored in soil transferred to hydrosphere
• deforestation effect on carbon cycle - absorption

  less leaf litter, so no humus formed, soil can't support much new growth = limited carbon absorbed
• deforestation effect on carbon cycle - clim change

  trees remove co2, no trees = more atmospheric co2 = enhances greenhouse effect
• effect of climate change - drought

  temps increasing and rainfall decreasing = drought = species extinction + forest fires
• amazon droughts when

  2015-16