Abstract
To investigate the structure and successional dynamics of microbial communities in shrimp culture ponds in coastal saline–alkali regions of Hebei, China, we compared the water microbiota of Litopenaeus vannamei monoculture ponds and L. vannamei–Macrobrachium rosenbergii polyculture ponds in the early, mid, and late culture stages. The results revealed clear temporal succession patterns in both the diversity and composition of microeukaryotic and bacterial communities. Distinct differences were also observed between the two culture models. Compared with monoculture, polyculture ponds showed 2.23–34.76% lower abundances of parasitic microeukaryotes, such as Rozellomycota and Perkinsida. In contrast, the abundances of carbon- and nitrogen-cycling bacterial groups (e.g., LD29, CL500-29_marine_group) and Chlorophyta were 0.24–50.94% higher in the polyculture system. Co-occurrence network analysis showed that polyculture enhanced competitive interactions and increased the network structural complexity within bacterial and cross-domain microbial networks. These findings help elucidate the mechanisms underlying efficient shrimp production in saline–alkali ponds and support the optimization of aquaculture models.