6.5.4 - Recycling within ecosystems ( NITROGEN CYCLE )

• what are the 4 reactions in the nitrogen cycle?

  1. Nitrification
  2. Ammonification
  3. Denitrification
  4. Nitrogen Fixation
• what happens in nitrification?

  conversion of Ammonium ions (NH4+) to Nitrites (No2-)to Nitrates (No3-)

  • Nitrosomonas oxidises ammonium ions to nitrites
  • nitrobacteria oxidises nitrites to nitratesw
  • this is an oxidation process
• what happens in ammonification?

  conversion of proteins --> ammonium ions

  due to decomposer bacteria
• what happens in denitrification?

  conversion of nitrates (NO3- ) into nitrogen (N2)

  by denitrifying bacteria (Pseudomonas)
• What happens in nitrogen fixation?

  conversion of nitrogen into nitrates/ ammonium ions

  
  

  energy release during lighting makes nitrates

  harbour process makes ammonium ions ( iron catalyst increases temp and pressure)

  nitrogen fixing bacteria (Azotobacterial/ Rhizobium) makes ammonium ions by nitrogen reductase. Anaerobic conditions provided by leghaemoglobin