Nutrient Cycles

Nutrient Cycles

1. Nitrogen Cycle

   • 1. Ammonification
     • is the production of ammonia from organic ammonium containing compounds such as urea which contains excessive amino acids.
   • 2. Nitrification
     • Free- living Nitrifying bacteria oxidise ammonia to nitrite. This is then oxidise to Nitrate ions. This process release energy.
   • 3.Nitrogen Fixation
     • Mutualistic Bacteria
       • lives in the nodules of leguminous plants.
         • Bacteria obtain the carbohydrates from the plants and Plants obtain amino acids from the baceria
     • Nitrogen Fixing bacteria
       • Convert nitrogen gas into ammonia
   • Denitrification
     • Anaerobic dentrifying bacteria convert soil nitrates into Nitrogen gas

2. Carbon cycle

   • Saprobiotic microganisms
     • Extracellular Digestion
       • They secrete enzymes on to the dead organisms and break down into simple molecules, which can then be absorbed
         • CO2 is released into the atmosphere when the microorganisms respire

3. Environmental Consequences of Fertilisers

   • Eutrophication
     • As the nitrate concentration increase, plants and algae grow exponentially and causes algal bloom. It forms a dense surface layer and prevents light reaching to lower depths. Light becomes a limiting factor. So plants and algae dies.

4. Fertilisers

   • Organic Fertilisers
     • Cheap
       • Less Soluble
         • improves soil structure by binding to soil particles together and provides food for soil organisms like earthworms
       • Improves drainage & aeration
   • Inorganic Fertilisers
     • Leaching

5. Greenhouse Gas

   • CO2, Methane, Water vapour
     • Burning combustion release CO2
     • Clearing
       • Less Photosynthetic organism so less CO2 removed

6. Global warming

   • an increase in the earth's average temperature
     • Deforestation increase CO2 conentration