13.5 - Leaching + eutrophication

• 3 issues nitrogen-containing fertilisers can cause ?

  Reduced species diversity, leaching, eutrophication
• Describe what leaching is and how it occurs ?

  • Nutrients are removed from soil
  • Rainwater dissolves soluble nutrients, like nitrate ions, and deep into soil
  • Drain into lakes and rivers
• Why is leaching harmful to the environment and what other issues can it cause ?

  • Can cause harmful ions to get into drinking water
  • Can cause eutrophication
• Describe how eutrophication occurs ?

  • Leaching occurs so there’s an increase in nutrients (eg nitrate ions)
  • Algal bloom occurs as plants grow as nutrients is no longer a limiting factor
  • Bloom prevents sunlight reaching lower depths
  • Light becomes limiting factor so plants at bottom die
  • Less photosynthesis so O2 conc depletes
  • Saprobionts breakdown dead plants so use up more O2 for respiration further depleting it
  • Aerobic organisms can’t survive so die
  • Anaerobic organism thrive and release toxic waste so water becomes putrid
• What is eutrophication mainly caused by ?

  Leaching of artificial fertilisers