👉 A denitrifier is a biological process that converts atmospheric nitrogen (N2) into nitrate (NO3-) and other compounds. This conversion of N2 to N3 is essential for the growth, survival, and reproduction of plants and bacteria in the atmosphere. Denitrifiers are found in many environments including forests, grasslands, deserts, and even in underground cave systems. They play a crucial role in maintaining the nitrogen cycle and promoting plant growth.