Effect of sulfate on surface sediment microorganisms in freshwater aquaculture ponds

Abstract:

The ecological effect of sulfate has attracted increasing attention, while little is known about the impact of sulfate on sediment microorganisms in aquaculture ponds. [Objective] To explore the influence rule and possible mechanism of different concentrations of sulfate on sediment microorganisms in aquaculture ponds. [Methods] The experimental systems were constructed with the sediment and surface water collected from an aquaculture pond. After the addition of 0 mg/L (control group), 30 mg/L (T1 group), 150 mg/L (T2 group), and 500 mg/L (T3 group) Na₂SO₄, the changes of the abundance, diversity, composition, and co-occurrence network of microbial community in the surface sediment were determined, and the environmental factors influencing the sediment microorganisms were analyzed. [Results] The sediment microbial communities showed little differences among groups within 30 days of incubation. On day 50, the microbial abundance and diversity in T2 and T3 groups decreased significantly compared with that of the control group. Compared with that in other groups, the relative abundance of Acidobacteriota and Bacteroidota in T1 group and that of Proteobacteria and Actinobacteriota in T3 group increased significantly (P<0.05). Compared with those in the control group, differential taxa increased in T1 group (62 taxa) and decreased in T3 group (45 taxa). The complexity of the microbial co-occurrence network was increased by high-concentration sulfate, which suggested that the microbial community might respond to the environmental changes caused by sulfate via self-regulation. The redundant analysis and correlation analysis revealed that the total organic carbon, total nitrogen, and oxidation-reduction potential of the sediment were the main environmental factors influencing the sediment microorganisms, suggesting that the sediment microorganisms might be affected by the interaction between sulfate and organic matter. [Conclusion] The long-time exposure to high concentrations of sulfate significantly affects the sediment microbial communities in aquaculture ponds, in which the transitions of microbial communities and changes in organic matter decomposition caused by sulfate may play a role.