Dynamics of Bacterial Communities and Their Relationship with Nutrients in a Full-Scale Shrimp Recirculating Aquaculture System in Brackish Water.

Microbial communities in RASs play a critical role in maintaining water quality and supporting shrimp growth, development, and health. However, their dynamics, particularly in commercial systems, remain poorly understood. This study aimed to improve the understanding of bacterial community dynamics during shrimp culture in RASs. High-throughput amplicon sequencing of the 16S rRNA, PERMANOVA, PCoA, and other statistical analyses were used to investigate the bacterial dynamics. The entire succession process was categorized into three distinct phases, the initial, middle, and final phases, during the shrimp rearing in RASs to elucidate the spatial-temporal dynamics of the bacterial communities. Alpha diversity indicates the evenness of the bacterial community increased in the initial phase, while richness peaked in the middle phase. Notable taxonomic and functional groups within the bacterial community contributed to significant variations in the relative abundance of community composition across these phases. The dominant bacterial phyla in both water and biofilm included Proteobacteria, Actinobacteriota, Bacteroidota, and Patescibacteria. The dominant orders in both environments were Corynebacteriales, Burkholderiales, Rhodobacterales, Flavobacteriales, Saccharimonadales, and Micrococcales. Key bacterial taxa such as