Abstract: The health status of shrimp (Litopenaeus vannamei) is highly correlated with the bacterioplankton communities in aquaculture water. Here, the dynamics of bacterioplankton diversity, composition and the association within key taxa were investigated by 16S rRNA highthroughput sequencing. The results showed that before the disease outbreak, the Shannon index of bacterioplankton in diseasedtrend ponds was significantly lower than that of the healthy ponds with a constant reduction. Accompanied by disease outbreaks, the bacterioplankton of diseased ponds was distinct from that of the healthy ponds, with community characterized by lower temporal stability. Before the disease onset, the average relative abundance of Chloroflexi, Saccharibacteria, and δproteobacteria in the diseased ponds were significantly higher than that in healthy ponds, while the change of Bacteroidetes was opposite. In addition, some diseaseindicated OTUs in the diseased ponds were affiliated with Vibriaceae and Flavobacteriaceae. OTU1 which belonged to Rhodobacteraceae was healthy indicator in healthy ponds before the disease outbreak. Results from the network analysis showed that most of the OTUs interacting with OTU1 belonged to the Flavobacteriaceae, which might play an important role in the bacterioplankton communities. Overall, the incidence of shrimp might be highly associated with a variety of bacterioplankton communities, and the opportunistic pathogens could rapidly multiply, leading to the incidence of shrimp when the “ecological niche opportunity” occurred. Preservation and restoration of bacterial community equilibrium would be an effective strategy for shrimp disease prevention.

Key words: soil, light fraction, heavy fraction, respiration, temperature sensitivity.