The Nitrogen Cycle

Atmospheric abiotic nitrogen(N₂) → ammonia(NH₃)(see: Nitrogen Fixation) → nitrates(NO₃(Nitrification) → plants(Assimilation In the nitrogen cycle) → animals(consumption) → ammonia(Decomposition In the Nitrogen Cycle) → Returning nitrogen to the atmosphere — Denitrification

• Nitrogen is an important for our DNA and proteins
• Nitrogen is a gas
• The atmosphere is made of 78% nitrogen(The atmosphere) but cannot be directly absorbed from the atmosphere for use by most organisms
  • Atmospheric Nitrogen(N₂) must first be converted to nitrates(NO₃)

• Bacteria in soil or roots(and lightning)(see: The lithosphere) can change nitrogen in the air (N₂) into ammonia. The ammonia must be converted into nitrates through nitrification.
  • Some bacteria convert nitrogen gas to ammonia (NH₃)
  • Lighting also performs nitrogen fixation. It produces ammonia
    • This process is called nitrogen fixation
    • These bacteria are called 'nitrogen fixing bacteria'

• Nitrifying bacteria convert ammonia(NH₃) into nitrates(NO₃)

• Nitrates(NO₃) can be absorbed by plants to make proteins and DNA. Plants will then pass it on to animals when consumed. (consumption)
• Plants take in nitrogen-rich compounds by assimilation

• When animals die, they release the nitrogen back into the soil

1. To return to the atmosphere, amonia is converted to nitrates, which is converted back to nitrogen gas by denitrifying bacteria in the soil.
2. This process is called denitrification

• Man made fertilizers convert nitrogen gas directly into ammonia
• This increases the amunt of usable nitrogen in the soil without relying on the natural cycle.
• More ammonia = more nitrates = more DNA.