What component of the nitrogen cycle converts ammonia to nitrites?

Nitrification is the process that specifically converts ammonia into nitrites. This process is carried out by specialized groups of bacteria that oxidize ammonia (NH3) to form nitrite (NO2-). Generally, this two-step process begins with the conversion of ammonia to nitrite by ammonia-oxidizing bacteria (AOB), such as Nitrosomonas. Following this, nitrite is further converted into nitrate (NO3-) by nitrite-oxidizing bacteria.

Nitrification is a crucial step in the nitrogen cycle because it transforms ammonia, which can be toxic at high concentrations, into nitrites and then nitrates, which are more easily utilized by plants as nutrients. This helps maintain ecological balance and promotes healthy plant growth.

The other components mentioned—nitrogen fixation, denitrification, and ammonification—play different roles within the nitrogen cycle. Nitrogen fixation involves converting atmospheric nitrogen (N2) into ammonia, denitrification reduces nitrates back to nitrogen gas, and ammonification refers to the conversion of organic nitrogen from dead organisms back into ammonia. Each process is vital for different aspects of nitrogen cycling, but it is nitrification that specifically addresses the conversion of ammonia to nitrites.