人工强制混合充氧对分层型水库细菌群落演替的影响

为深度解析人工强制混合充氧过程中细菌群落的演替,以西安金盆水库为研究对象,对2018年8月~2019年4月水库主库区垂向细菌种群结构进行连续监测.结果表明,受人工强制混合充氧作用影响,水库水体中的优势菌群蓝细菌门（Cyanobacteria）的丰度由11.7%~19.2%降至6.3%~8.9%.其中,表层、中层和底层水体蓝细菌的丰度分别由18.3%、11.7%、19.2%降至8.9%、6.3%、7.9%.人工强制混合作用使垂向水体细菌的种群结构差异降低,样本之间的离散度逐渐减小,其中优势菌群放线菌门（Actinobacteria）和变形菌门（Proteobacteria）在水体垂向的丰度分别由"中 > 底 > 表"和"表 > 底 > 中",逐渐变为表、中、底层趋于均一.人工强制充氧作用使底部水体溶解氧（DO）含量逐渐升高,好氧型细菌的丰度得到明显的增加,其中Polynucleobacter的丰度从0.06%增加到1.06%,甲基孢囊菌属（Methylocystis）的丰度由0.18%增至2.20%,甲基杆菌属（Methylobacter）的丰度由0.02%增加到1.96%.通过冗余分析可知,影响细菌群落组成的主要因素为水体热分层稳定性、水温、DO、总磷（TP）和总氮（TN）.

The effect of artificial forced mixingand oxygenating on the bacterial community succession in the stratified reservoir

To explore the influence of artificial forced mixing and oxygenating on the bacterial community structure, we analyzed the bacterial community structure in Xi'an Jinpen reservoir from August 2018 to April 2019. The results showed that Cyanobacteria、Actinobacteria and Proteobacteria were the dominating bacteriaes in the whole water. The abundance of Cyanobacteria decreased from 11.7%~19.2% to 6.3%~8.9% due to the artificial forced mixing and oxygenating. The abundance of Cyanobacteria decreased from 18.3%、11.7%、19.2% to 8.9%、6.3%、7.9% in surface、middle and bottom water. The difference of the bacteria structure and the dispersion between samples were reduced because of the artificial forced mixing effect. Theabundances of Actinobacteria and Proteobacteria gradually change from "middle > bottom > surface" and "surface > bottom > middle" to be consistent in the surface、middle and bottom water. Thecontent of dissolved oxygen and the abundance of aerobic bacteria were increased due to the artificial forced oxygenation effect at the bottom. The abundances of Polynucleobacter、Methylocystis、Methylobacter increased from 0.06%、0.18%、0.02% to 1.06%、2.20%、1.96%. According to the redundancy analysis, the mainfactors that affected bacterial community composition were the thermal stratification stability,water temperature, DO, TP and TN.