Dynamic Change of Sedimental Microbial Community During Black Bloom-an In Situ Enclosure Simulation Study

Black bloom is a worldwide environmental problem. Sediment microbes play important roles in the process of black bloom. The dynamic change of sedimental microbial community and their potential link between taste and odor compounds during black bloom was investigated in an in situ black bloom enclosure simulation experiment. Through high-throughput sequencing and analysis, pronounced shifts of sedimental microbial community were observed on the 3rd and 7th day in the black bloom group. Microbes in Cyanobacteria, Verrucomicrobia, Planctomycetes, and Actinobacteria were obviously increased, while microbes from the phyla OP8, Chloroflexi, and Acidobacteria were decreased significantly. RDA analysis revealed that the concentrations of chlorophyll a (Chla), total phosphorus (TP), and turbidity (NTU) in the water and the TP, TN concentrations in the sediment were the main environmental factors that affect the microbial community in the sediment. Correlation analysis revealed that microbes Dechloromonas sp. (OTU003567 and OTU000093), Desulfococcus sp. (OTU000911), Chromatiaceae (OTU001222), and Methanosaeta sp. (OTU004809) were positively correlated with the taste and odor substances in the sediment, such as dimethyl sulfide (DMS), β-ionone, β-cyclocitral and geosmin. The sedimental microbial community gradually recovered in the late phase of black bloom, indicating the stability and self-recovery ability of the sedimental microbial community during black bloom. Noteworthily, we observed many possible pathogens increased significantly during the black bloom, which alerts us to keep away from contaminated sediment when black bloom occurred.