What are the key processes in the nitrogen cycle?
Identify which compounds are involved in each process.
The key processes in the nitrogen cycle include nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.
1. Nitrogen fixation: This process converts atmospheric nitrogen (N2) into ammonia (NH3) or ammonium (NH4+). This is done by nitrogen-fixing bacteria, which either live freely in the soil or form symbiotic relationships with certain plants.
2. Nitrification: This process involves the conversion of ammonia (NH3) or ammonium (NH4+) into nitrites (NO2-) and then into nitrates (NO3-). It is carried out by nitrifying bacteria.
3. Assimilation: This process involves the incorporation of nitrates (NO3-) or ammonia (NH3) into organic compounds like proteins and nucleic acids by plants and algae. These compounds are then consumed by animals.
4. Ammonification: This process is the conversion of organic nitrogen (from dead plants and animals) into ammonia (NH3) by decomposer bacteria and fungi.
5. Denitrification: This process converts nitrates (NO3-) back to atmospheric nitrogen (N2). Denitrifying bacteria carry out this conversion in environments with low oxygen levels.
Overall, the key compounds involved in these processes are atmospheric nitrogen (N2), ammonia (NH3) or ammonium (NH4+), nitrites (NO2-), nitrates (NO3-), organic nitrogen, and atmospheric nitrogen (N2) again.