Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas ( N ₂ ) to the atmosphere?

Step-by-step solution

Denitrification is a chemical process in which nitrates in the soil are reduced to molecular nitrogen ( N ₂ ) which is released into the atmosphere. It is done by denitrifying bacteria like Pseudomonas. Anaerobic oxidation of ammonium ( NH ₄ ) also releases nitrogen in the atmosphere. Related Theory Anammox (anaerobic ammonium oxidation), which is a reaction that oxidizes ammonium to dinitrogen gas using nitrite as the electron acceptor under anoxic conditions, was an important discovery in the nitrogen cycle.