河套平原灌溉间隙期乌梁素海水体细菌群落结构特征

Characteristics of Bacterial Community Structure in Wuliangsu Lake During an Irrigation Interval in Hetao Plain

为研究河套平原末端乌梁素海在灌溉间隙期水体中细菌群落组成和相应的功能,于2020年9月开展湖上取样工作并对pH、TN、TP、DIP、DTP、NH_(4)^(+)-N、Chla、EC和SAL等指标进行分析.利用16S rRNA高通量测序方法对乌梁素海表层水15个样本中附着细菌和浮游细菌分别进行测定.结果表明:(1)附着细菌丰富度和群落多样性大于浮游细菌,而在均匀度上两者中位数相同;(2)前五大优势细菌门类中Proteobacteria和Actinobacteriota各取样点浮游细菌均明显高于附着细菌,Bacteroidota中附着细菌和浮游细菌各取样点丰度高低交错,相反,Verrucomicrobiota和Cyanobacteria中各取样点附着细菌的含量均高于浮游细菌;(3)冗余分析显示,pH对优势附着细菌的影响最为显著,优势浮游细菌中电导率和盐度的影响最为显著;(4)PICRUSt2功能预测分析表明,附着细菌和浮游细菌代谢功能最强,表现出丰富的代谢功能.其中共有29个氮相关的有效KO和88个磷相关的有效KO,以固氮功能和无机磷溶解功能最强,且浮游细菌在两种功能中发挥着更大的作用.

In order to study the bacterial community composition and corresponding function in Wuliangsu Lake at the end of the Hetao Plain during the irrigation gap period,lake samples were collected in September 2020,and the pH,TN,TP,DIP,DTP,NH_(4)^(+)-N,Chla,EC,SAL,and other indicators were analyzed.The 16 S rRNA high-throughput sequencing method was used to explore the attached bacteria and bacterioplankton in 15 samples of the surface water in Wuliangsu Lake.The experimental results showed that:(1)the alpha diversity Chao and Shannon indices of attached bacteria were greater than that of bacterioplankton,but the median of Shannoneven index was the same.(2)In each sampling point,the bacterioplankton of Proteobacteria and Actinobacteria in the top five dominant bacteria phyla were higher than that of attached bacteria,and the abundance of attached bacteria and bacterioplankton of Bacteroidota were staggered.On the contrary,the contents of attached bacteria of Verrucomicrobiota and Cyanobacteria were all higher than that of bacterioplankton.(3)Redundant analysis showed that pH had the most significant effect on dominant attached bacteria,and the effect of conductivity and salinity in dominant bacterioplankton was the most significant.(4)PICRUSt2 function prediction analysis showed that attached bacteria and planktonic bacteria had the strongest metabolic functions,showing abundant metabolic functions.There were 29 nitrogen-related effective KOs and 88 phosphorus-related effective KOs,with the greatest nitrogen-fixing function and strong inorganic phosphorus-dissolving function,and bacterioplankton played a greater role in the two functions.