Which bacteria are primarily involved in the nitrification process?

The nitrification process is a critical part of the nitrogen cycle, where ammonia is converted into nitrate, making it available for plant uptake. This process occurs in two main steps, each facilitated by specific types of bacteria.

In the first step, ammonia (NH₃) is oxidized to nitrite (NO₂⁻) by ammonia-oxidizing bacteria, with Nitrosomonas being one of the key genera involved. In the second step, nitrite is further oxidized to nitrate (NO₃⁻) by nitrite-oxidizing bacteria, primarily represented by Nitrobacter. These two groups of bacteria, Nitrosomonas and Nitrobacter, work together in a sequence to effectively convert ammonia into nitrate, which is vital for the ecological assimilation of nitrogen by plants and other organisms.

Other options in the question refer to different bacteria that play roles in other processes. For example, Desulfovibrio is involved in sulfate reduction, while Pseudomonas and Aerobacter are more generalist bacteria that can participate in various metabolic processes but are not specifically tied to nitrification. Therefore, Nitrosomonas and Nitrobacter are the primary bacteria involved in the nitrification process, leading to their designation as the