硫酸盐对淡水养殖池塘表层底泥微生物的影响

Effect of sulfate on surface sediment microorganisms in freshwater aquaculture ponds

摘要:

硫酸盐引起的生态学效应已得到了越来越多的关注，但目前关于硫酸盐对养殖池塘底泥微生物的影响还知之甚少。【目的】探究不同浓度硫酸盐对养殖池塘底泥微生物的影响规律及可能的机制。【方法】本研究利用采集自养殖池塘的底泥和表层水构建了试验系统，研究了加入约0 mg/L （对照组）、30 mg/L （T1处理组）、150 mg/L （T2处理组）、500 mg/L （T3处理组） Na₂SO₄后表层底泥微生物的丰度、多样性、组成和共生网络的变化规律，并分析了环境影响因素。【结果】孵育第30天前，各实验组底泥微生物变化不大；但到第50天时，T2和T3处理组微生物丰度和多样性相比对照组均明显下降。相比其他实验组，T1处理组酸杆菌门（Acidobacteriota）、拟杆菌门（Bacteroidota）相对丰度出现显著升高（P<0.05），T3处理组变形菌门（Proteobacteria）和放线菌门（Actinobacteriota）相对丰度出现显著升高（P<0.05）。与对照组相比，T1处理组增加了较多差异类群（62种），而T3处理组差异类群大量减少（45种）。共生网络图分析显示硫酸盐浓度的增加引起了底泥微生物网络复杂性的增加，说明微生物群落可能通过自身的调节来响应硫酸盐引起的环境改变。冗余分析（redundant analysis，RDA）和相关性分析揭示底泥总有机碳、总氮和氧化还原电位是影响底泥微生物的主要环境因素，提示底泥微生物可能受到硫酸盐和有机质作用的影响。【结论】较长时间的高浓度硫酸盐会对池塘底泥微生物群落造成重要影响，微生物群落自身的转变和硫酸盐引起的有机质分解改变可能是造成微生物群落变化的关键因素。

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.