Bacterial diversity and community composition in lake water and sediment of Lake Daihai

Abstract

采用高通量测序技术，研究了内蒙古岱海流域入湖河流、湖水及沉积物细菌多样性及群落组成.结果显示，细菌多样性从高到低依次为：沉积物>河流>湖泊.聚类分析表明入湖河流、湖水和沉积物细菌群落可分为明显不同的3支，说明这3种生境中细菌群落结构有较大差异.物种注释结果表明，河流中优势细菌菌群为髌骨细菌（Patescibacteria）、变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）和放线菌门（Actinobacteria）；湖水中优势细菌菌群为放线菌门（Actinobacteria）；而沉积物中优势细菌菌群为变形菌门和绿弯菌门（Chloroflexi）.典范对应分析及Monte Carlo检验表明，电导率和悬浮物含量对水体中（河流与湖泊）细菌群落影响显著，二者共解释了细菌群落变化的86.5%；而冗余分析及Monte Carlo检验表明，泥深、磁化率和总有机碳对沉积物中细菌群落影响显著，三者共解释了细菌群落变化的47.9%.近30年来，岱海地区气候变化和人类活动导致湖水咸化，沉积物碳氮指标显著增长.岱海水体及沉积物细菌多样性及群落组成的差异及其主要驱动因子，反映了细菌对这种气候变化和人类活动共同作用的响应.;Bacterial diversity and community composition was investigated in the Lake Daihai Basin, Inner Mongolia using high-throughput sequencing technology. The results showed that bacterial diversity was highest in sediments, followed by river and lake water. Cluster analysis showed that bacterial community compositions in the inflowing river, lake water and sediments were separated into three distinct groups, indicating great differences in bacterial community compositions among the three habitats. Taxonomic annotation showed that the dominant bacterial flora in the river was Patescibacteria, Proteobacteria, Bacteroidetes and Actinobacteria. Actinobacteria was the most dominant bacteria phylum in the lake water, while the dominant bacterial flora in sediments were Proteobacteria and Chloroflexi. Canonical correspondence analysis and Monte Carlo permutation test revealed that the variations of bacterial community compositions in the river and lake were significantly explained by conductivity and suspended solids, which explained 86.5% of the variation. Redundant analysis and Monte Carlo permutation test revealed that the variations of bacterial community compositions in sediment were significantly explained by depth, magnetic susceptibility and total organic carbon, which explained 47.9% of the variation in total. During the past 30 years, Lake Daihai has experienced salinization in lake water and a remarkable increase of carbon and nitrogen in the sediment due to climate change and anthropogenic activities. The variations of bacterial diversity and community composition in the water and sediments, as well as their main driving environmental factors, highlight the responses of bacteria to the combined effects of climate change and anthropogenic activities on Lake Daihai.