• They are called biogeochemical cycles (Nitrogen, phosphorus and carbon cycle)

Nitrogen cycle

• Plants obtain nitrogen in the form of nitrates.
• Animals obtain it through the food chain.

Nitrogen Fixation

• Nitrogen fixation is the conversion of nitrogen gas to nitrate compounds.
• Bacteria help in the nitrogen fixation process.
  • They stay in the roots of some legumes.

Denitrification

• Nitrate compounds are converted back into nitrogen gas.
• Denitrifying bacteria are active in areas that have a deficit of oxygen.

Human Impact

• Human impacts have dramatically changed the nitrogen cycle.
• The amount of nitrogen gas has almost doubled.
• Air pollution and fertilizers.

From Class

Process of transfer of nitrogen

• There 78% of nitrogen in the atmosphere
• It’s essentially for organisms
  • Preparation of Fats and Proteins in organisms
  • Example: Chlorophyll in plant is made from protein, its there in DNA and RNA (basis of life).
• Atmosphere - Soil - Plants - Animals