 The can be assimilated by anabolism while the ammonia and organic by-product released by Nitrospira allow ammonium oxidizers and other microbes to co-exist in the same microenvironment.All members of this genus have the nitrite oxidoreductase genes, and thus are all thought to be nitrite-oxidizers.Ever since nitrifying bacteria were discovered it was accepted that nitrification occurred in two steps, although it would be energetically favourable for one organism to do both steps.