Nitrification

Definition

Nitrification is the microbial process of converting ammonia (NH3) into nitrite (NO2-) and then into nitrate (NO3-). This process is essential for the nitrogen cycle in ecosystems.

5 Must Know Facts For Your Next Test

1. Nitrification involves two main steps: ammonia oxidation to nitrite by ammonia-oxidizing bacteria (AOB) and nitrite oxidation to nitrate by nitrite-oxidizing bacteria (NOB).
2. The primary genera of AOB include Nitrosomonas and Nitrosococcus, while common NOB genera include Nitrobacter and Nitrospira.
3. Nitrification is an aerobic process, requiring oxygen for the oxidation reactions.
4. It plays a crucial role in soil fertility, as nitrate is a more accessible form of nitrogen for plant uptake than ammonia.
5. In aquatic environments, nitrification can contribute to eutrophication if excess nutrients lead to algal blooms.

Review Questions

• What are the two main steps involved in nitrification?
• Name two genera each of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).
• Why is nitrification important for soil fertility?

Related terms

Ammonification: The process of converting organic nitrogen into ammonia.

Denitrification:

The microbial reduction of nitrate or nitrite to gaseous forms of nitrogen, such as N2 or N2O.

Nitrogen Fixation:

The conversion of atmospheric nitrogen (N2) into a biologically usable form like ammonia.