Response of sediment bacterial communities to the drainage of wastewater from aquaculture ponds in different seasons

Bacterial communities play an important role in diffuse sediment pollution in aquaculture farms. Previous studies have revealed the short-term influence of wastewater drainage on the bacterial communities but the seasonal response of the sediment bacterial communities to wastewater drainage from aquaculture farms remains unclear. This study used the 16S rRNA approach to explore the profiles of bacterial communities over four seasons in a typical crab aquaculture farm that included a pond and an outlet ditch. Nineteen sediment samples and an equal number of water samples were collected and analysed during spring, summer, autumn, and winter during 2018-19. Our results showed that Proteobacteria, Chloroflexi, and Bacteroides were the predominant phyla in aquaculture pond sediment with the relative abundance of 28.95%, 17.32%, and 15.31%, respectively. The relative abundance of Proteobacteria and Bacteroides was higher in autumn and winter, and the relative abundance of Chloroflexi was highest in spring. The Shannon diversity index value ranged from 6.17 to 9.30 and showed significant positive correlation (P 0.01) with the concentrations of TN, NH