太湖不同湖区冬季沉积物细菌群落多样性

为了探究太湖不同营养水平湖区冬季沉积物细菌群落多样性，利用高通量测序对太湖水草区、湖心区和河口区共9个采样点表层沉积物细菌的16S rRNA基因进行序列测定.结果发现：不同湖区的物种丰富度和均匀度为水草区 > 湖心区 > 河口区；不同湖区优势细菌群落组成存在差异.其中，硝化螺旋菌门（Nitrospirae）和酸杆菌门（Acidobacteria）2类门水平优势细菌以及厌氧绳菌纲（Anaerolineae）和硝化螺菌纲（Nitrospira）2类纲水平优势细菌在不同湖区之间差异显著.冬季太湖沉积物细菌优势类群为绿弯菌门（Chloroflexi）、变形菌门（Proteobacteria）、蓝藻门（Cyanobacteria）和硝化螺旋菌门（Nitrospirae）；在属分类水平上，主要优势类群为unidentified_Chloroplast和微囊藻属（Microcystis）.Cyanobacteria和Microcystis在所有采样点均有检出，平均丰度均以湖心区最高.对沉积物细菌群落与环境因子的关系进行冗余分析，结果表明：营养盐水平、水温和pH值均能影响沉积物细菌群落结构，NO₃^--N和水温是Microcystis的主要影响因子.

The diversity of bacterial communities in the sediment of different lake zones of Lake Taihu in winter

To explore the diversity of bacterial communities in the sediment of different lake zones with varied nutrition levels in Lake Taihu in winter, the 16S rRNA gene of surficial sedimentary bacteria of 9sampling sites, including the estuary area, the lake center and the macrophyte-dominated area, was sequenced using high-throughput sequencing approach. The results showed that the species richness and evenness was the highest in the macrophyte-dominated area, moderated in the lake center, while lowest in the estuary area. The composition of bacterial communities varied among lake zones:the phyla of Nitrospirae and Acidobacteria, and the classes of Anaerolineae and Nitrospira, specifically showed significant difference among lake zones with different nutrition levels. At the phyla level, Proteobacteria, Chloroflexi, Cyanobacteria and Nitrospirae were dominant. unidentified_Chloroplast and Microcystis were dominant bacteria at the genus level in the surficial sediments of Lake Taihu in winter. Cyanobacteria and Microcystis were detected ubiquitously at all sampling sites with the highest average abundance appearing in the center of Lake. The redundancy analysis (RDA) for the relationship between bacterial communities and environmental factors revealed that the nutrition level, water temperature and pH could affect the bacterial community structure in sediment. The level of nitrate nitrogen (NO₃^--N) and water temperature were the major environmental factors affecting the genus of Microcystis.