纳木措湖沿岸表层水细菌群落特征及影响因素

Characteristics and effective factors of bacterial community in surface water along the coast of Namtso lake

为了探究夏季纳木措湖沿岸表层水体细菌群落特征,为以后纳木措湖细菌的研究打下基础,围绕纳木措湖一周选取采样点19个。现场采集水样,进行理化因子测定,运用高通量测序技术获取上述样点的16S rDNA数据,根据多样性指数和丰富度指数计算比较各样点的细菌群落多样性和丰富度,根据各样点细菌群落在门和属水平的分布来研究纳木措各样点细菌分布差异,基于Spearman相关性系数来衡量理化因子与α-多样性指数的相关性,采用冗余分析(redundancy analysis,RDA)探究理化因子与细菌群落分布之间的关系。在纳木措水体中共获得细菌4137个OTU(operational taxonomic units),属于87门204纲498目645科1185属。门水平优势菌群为变形菌门(Proteobacteria,39.61%)、拟杆菌门(Bacteroidetes,13.41%)和厚壁菌门(Firmicutes,12.61%),其中,变形菌门以γ-变形菌为优势菌群,其次为β-变形菌和α-变形菌。属水平有71.67%的未知细菌菌属。纳木措Shannon多样性指数显示,纳木措细菌种类比较丰富。Spearman相关性系数显示,水体细菌α-多样性指数与环境因子之间没有相关性。RDA分析表明,影响纳木措水体细菌群落结构的主要理化因子为温度(P=0.002,F=5.7)。纳木措沿岸表层水体细菌群落分布差异较为明显,细菌群落比较丰富,有许多未知菌种需进一步鉴定,有广阔的研究前景。

To explore the characteristics of bacterial community in the coastal surface water of Namtso in summer,and lay a foundation for the study of Namtso bacteria in the future,a total of 19 sampling sites were selected around Namco lake.Water samples were collected and physicochemical parameters were determined.16S rDNA data of the sites were obtained by high-throughput sequencing technology.The differences of bacterial distribution in various Namtso sites were studied according to the bacterial community distribution at phylum and genus levels.The correlation between physicochemical parameters andα-diversity index was measured based on Spearman correlation coefficient,and the relationship between physicochemical parameters and bacterial community distribution was investigated by redundancy analysis(RDA).A total of 4137 OTUs(operational taxonomic units)were obtained from Namtso,belonging to 87 phyla,204classes,498 orders,645 families and 1185 genera.Proteobacteria(39.61%),Bacteroidetes(13.41%)and Firmicutes(12.61%)were the dominant groups at phylum level.Gama-proteobacteria was the dominant group of Proteobacteria,followed by Beta-proteobacteria and Alpha-proteobacteria.There were 71.67%unknown species at the genus level.Shannon diversity index shows that Namtso has rich bacterial species.Spearman correlation coefficient shows that there was no correlation betweenα-diversity index and environmental factors.RDA analysis shows that temperature(P=0.002,F=5.7)is the main physicochemical factor affecting bacterial community structure in Namtso waters.There are obvious differences in the distribution of bacterial communities in the surface waters along the Namtso coast,and the bacterial communities are relatively rich.There are still many unknown bacterial species that need to be further identified and have broad research prospects.