Competitive-cooperative microbial dynamics drive water quality regulation in industrial recirculating shrimp aquaculture

Carbon (C) and nitrogen (N) content in recirculating aquaculture systems (RAS) are considered key to maintaining water quality stability, primarily governed by feeding and microbial processes. However, the interaction between dynamic changes in C and N content and microbial community structure remains unclear, which limits technological innovation. This study aims to investigate the relationship between C and N dynamics and microbial community structure in L . vannamei aquaculture. The results demonstrated that microbial community structure was primarily shaped by C and N metabolic taxa. From early (25 d) to mid-culture (50 d), a decrease in N-removing genera ( e . g ., Ferruginibacter and Microbacterium ) correlated with rising NO 3 - -N (20.52 to 47.78 mg L -1 ), while an increase in C-removing genera ( e . g ., Polynucleobacter and Jeongeupia ) paralleled the decline in COD (222.50 to 191.50 mg L -1 ), indicating competitive interaction between functional groups. In the late period (after 50 d), the community stabilized with high structural similarity to earlier period, suggesting functional convergence and coexistence after succession. This study elucidates the dynamic co-occurrence patterns between microbial functional groups throughout shrimp growth, offering novel insights for precise water quality management in recirculating aquaculture systems. • Microbial community structure in RAS was shaped by C- and N-related taxa • The coexistence mode of C- and N-taxa was competition followed by collaboration • Water quality was determined by characteristic taxa with C- or N- removal function