Nitrogen Cycle

Nitrogen is one main element for produce of protein and DNA. N2 (Nitrogen gas) makes up about 78% of the atmosphere but most organisms can't use it directly.

1. Nitrogen Fixation: Nitrogen-fixing bacteria convert nitrogen gas (N2) into ammonium (NH4+), a form of Nitrogent that can be absorbed and used by plants.

2. Nitrification: Nitrifying bacteria then convert ammonium into Nitrite (NO2-) and then into Nitrate (NO3-). Nitrate is the main form of Nitrogen used by plants.

3. Denitrification: Denitrifying bacteria converts Nitrate(NO3-) and Nitrite(NO2-) back into Nitrogen gas (N2) or Nitrous oxide (NO2).
   1. This prevents build up of nitrates, which prevents eutrophication (algae bloom) and nitrogen contamination.

4. Ammonification: Microbes (decomposers, bacteria & fungi) break down organic matters and convert nitrogen compounds into Ammonium (NH4+).

5. Assimilation: Plants, animals, and microbes take up Nitrogen compounds from the environment and produce biomasses (e.g. Protein & DNA).