Mechanisms governing the initiation and maintenance of partial nitrification from a microbial ecological perspective

This study reconceptualized partial nitrification from a microbial ecological perspective by elucidating the dynamic competition between AOB and NOB across the initiation， maintenance， and destabilization phases. Continuous selection pressure was proposed as the core determinant of process stability within a community-process coupled framework. The review indicates that the initiation depends on non-steady-state disturbances that amplify AOB growth advantages， whereas the maintenance phase is characterized by a metastable state with dynamic community structure but relatively stable function， where NOB persist at low abundance or under spatial constraint. When cumulative disturbances weaken AOB competitiveness， NOB can rapidly rebound， inducing a critical shift from partial to complete nitrification. Accordingly， operational strategies centered on resource supply， niche constraint， and community feedback are outlined， emphasizing window-period management to enhance system resilience. The alignment of time-resolved community data with key operational parameters is further discussed as a basis for identifying instability thresholds and early-warning signals to support predictive control and risk management in partial nitrification processes.