Nitrifying bacteria are a group of microorganisms that play a crucial role in the nitrogen cycle. They convert ammonia, which can be toxic to aquatic life, into nitrites and then into nitrates. This process is essential for maintaining healthy ecosystems, particularly in soil and water environments. These bacteria are typically found in soil, freshwater, and marine environments. The two main types of nitrifying bacteria are Nitrosomonas, which oxidize ammonia to nitrite, and Nitrobacter, which convert nitrite to nitrate. This transformation helps plants absorb nitrogen, an essential nutrient for growth.