Niche differentiation of comammox Nitrospira and canonical ammonia oxidizers in soil aggregate fractions following 27-year fertilizations

Abstract

Complete ammonia oxidizers (comammox Nitrospira) were recently discovered to be capable of oxidizing ammonia and nitrite in a single microorganism, which refutes the long-held paradigm that nitrification required two distinct groups of microbes. However, the niche differentiation of comammox Nitrospira and their co-occurrence with ammonia-oxidizing archaea (AOA) and bacteria (AOB) remain elusive in different soil aggregates. Here, we investigated how 27-year application of mineral and/or organic fertilizers affects comammox Nitrospira, AOA and AOB in aggregates from an Ultisol. Aggregate sizes significantly influenced the community structure of AOA and AOB, rather than comammox Nitrospira. H..