The 3 steps of the nitrogen cycle in order starting with nitrogen gas in the atmosphere are
1. Nitrogen Fixation: This process involves converting atmospheric nitrogen gas (N2) into a form that can be used by plants and other organisms. This can be achieved through two main methods: biological nitrogen fixation, carried out by nitrogen-fixing bacteria that can convert N2 into ammonia (NH3) or ammonium ions (NH4+), and industrial nitrogen fixation, which involves the production of fertilizers and other nitrogen-containing chemicals.
2. Nitrification: After nitrogen fixation, ammonia or ammonium ions are converted into nitrite ions (NO2-) by nitrifying bacteria. This process, known as nitrification, occurs in two steps: ammonia is first oxidized into nitrite by ammonia-oxidizing bacteria, and then nitrite is further oxidized into nitrate (NO3-) by nitrite-oxidizing bacteria. Nitrate is the main form of nitrogen that can be readily taken up by plants.
3. Denitrification: Denitrification is the final step in the nitrogen cycle, where nitrate is converted back into atmospheric nitrogen gas. This process is carried out by denitrifying bacteria in oxygen-deficient environments, such as waterlogged soils or sediments. Denitrification releases nitrogen gas (N2) into the atmosphere, completing the nitrogen cycle.