Barrons AP Environmental Science

14. (B) Nitrosomonas bacteria oxidize ammonia to nitrite: NH 3 → NO 2 –.

Nitrobacter then    oxidize nitrite to  nitrate:    NO 2 –  →   NO 3 – .    Denitrifying

bacteria    anaerobically   reduce  nitrate to  nitrogen    gas:    NO 3 –  →   N 2.