The oxidation of ammonium ions is part of:
“Nitrification” for the oxidation of ammonium ions is part of. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecosystem processes are constrained by energy conservation and by the cycling of matter. Energy enters mainly through primary production, is lost as metabolic heat at every transfer, and therefore cannot be recycled in the way that carbon, nitrogen, phosphorus, or water can. The remaining alternatives—“Fixation”, “Denitrification”, “Mineralization”—refer to different states, processes, or
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 18
