Nitrogen

• Aerobic processes:

  • Nitrogen fixation
  • Ammonification
  • Oxidation
• Anaerobic processes:

  • Denitrification
• Nitrogen fixation

  • Rhizobium perform nitrogen fixation
  • Legumes have root nodules on their roots that contain the rhizobium
  • the rhizobium give the nitrogen to the legumes to form amino acids and proteins
• Bacteria perform ammonification, oxidation and denitrification
• Rhizobium perform nitrogen fixation in root nodules and the soil
• Complete store labels

  A) Atmosphere

  B) Plants

  C) Animals

  D) Dead Organic Matter

  E) Ammonia

  F) Nitrites

  G) Nitrates

  H) Water bodies

  
• Complete process labels

  A) Nitrogen fixation

  B) Eaten

  C) Death

  D) Ammonification

  E) Oxidation

  F) Oxidation

  G) root absorption

  H) denitrification

  I) Ionisation

  J) Nitrogen fixation

  K) leaching

  
• Complete types of nitrogen labels

  A) NOx N2

  B) Amino acids and protein

  C) Amino acids and proteins

  D) amino acids and proteins

  E) NH3

  F) NO2 -

  G) NO3 -

  
• Complete extra info labels

  A) Rhizobium

  B) Legumes

  C) Root nodules containing rhizobium

  D) Bacteria

  E) Bacteria

  F) soluble

  G) dissolved in water

  H) bacteria

  I) Lightning

  
• Human impacts on the nitrogen cycle:

  • Artificial fertiliser use - nitrogen poisoning
  • Eutrophication
  • NOx - combustion engines
  • Agriculture - ploughing
• Human impacts on the nitrogen cycle:

  • Artificial fertiliser and nitrogen compounds in the soil can leach into water bodies - Eutrophication
  • Farmland is fertilised. Fertiliser leaches/percolates into water bodies.
  • Algae uses it first and causes an algal bloom. This covers the surface of the water and uses it all for photosynthesis.
  • Aquatic plants die due to lack of light for photosynthesis
  • bacteria breaks down dead plants, using up oxygen in the water that is not replaced by the plants.
  • Animals cannot aerobically respire so die due to deoxygenation
  • Algae dies and releases toxins
• Human impacts on the nitrogen cycle:

  Agriculture - ploughing - churns up the soil to mix fertile and non-fertile soil. This adds oxygen to the soil:

  • increase aerobic processes
  • increase in nitrates
  • increase of nitrates absorption into plants
  • increase plant growth

  It also decreases anaerobic processes

  • less nitrates are removed from the soil - plant legumes to increase nitrogen fixation - use artificial fertiliser
• Reducing human impacts:

  • Use organic fertiliser and more natural methods to increase nitrogen e.g manure
  • Crop rotation - change the type of crop in fields each year to allow nutrients to replenish naturally
  • Farming location - away from water bodies, do not use artificial fertiliser near water, drip irrigation to reduce runoff, buffer strip of hedges or trees
  • NOx - electric cars and catalytic converters
  • ion exchange - clean water for drinking, stops nitrogen poisoning