The Nitrogen Cycle

1. Denitrification

1.1. Denitrifying bacteria

1.1.1. Release into atmosphere

2. Importance of nitrogen

2.1. Amino acids

2.1.1. Proteins

2.2. Nucleic acids (DNA, RNA)

2.3. Limiting macronutrient for plants

3. Biological fixation

3.1. Animal waste

3.1.1. Ammonification by detritivores

3.2. Nitrogen fixing bacteria in legume roots or in soil

3.2.1. Nitrogren fixation into ammonium

3.2.1.1. Nitrification into nitrates by bacteria

4. Industrial fixation

4.1. Exhaust gasses

4.2. Fossil fuel emission

4.3. Fertilizers

5. Atmospheric fixation

5.1. Nitrogen reservoir in atmosphere

5.2. Lightning breaks nitrogen molecules allowing them to form nitrous oxides with oxygen