长江中游吞吐调蓄型湖泊细菌群落组成变化的季节同步性规律研究

In lake ecosystems, bacteria not only comprises a large fraction of biomass，but also plays a crucial role in nutrient cycling and energy flow. Knowing the bacterial community composition, diversity and spatiotemporal distribution patterns are of great significance for understanding the lake ecosystems comprehensively. So far, there are few studies concerning seasonality and synchrony in bacterial community composition of different lakes at a regional scale. The relative importance of intrinsic (site-specific) and extrinsic (regional) drivers is a topic of much debate. Poyang Lake and Dongting Lake, which are typical regulating lakes located in middle reaches of Changjiang River, are the first and second largest freshwater lake in China, respectively. The present study aims at exploring the seasonality and synchrony in bacterial community composition and its driving forces of regulating lakes located in middle reaches of Yangtze River by field sampling, 454 sequencing and statistical analysis. It will facilitate a better understanding of the distribution characteristics and formation mechanisms of bacteria communities in lakes.

在湖泊生态系统中，细菌不仅是生物量的重要组成部分，对于物质循环和能量传递过程也起着关键的作用。掌握湖泊细菌群落的组成、多样性以及它们的分布规律对于深入的了解湖泊生态系统具有重要的意义。目前为止，关于区域尺度上不同湖泊细菌群体组成季节变化规律的比较研究十分缺乏，湖泊生态系统的内部因子和区域尺度上的外部因子各自扮演着什么角色存在不少的争议。鄱阳湖和洞庭湖分别是我国第一、第二大淡水湖，也是长江中游典型的吞吐调蓄型湖泊。本项目拟通过野外采样、454测序结合后续统计分析手段首次系统的研究长江中游吞吐调蓄型湖泊的细菌群体组成的季节变化、同步性规律以及环境因子的驱动作用，填补此特殊类型湖泊微生物生态学研究的空白，有利于更好的理解湖泊生态系统细菌群落分布特征和形成机制，对湖泊细菌群体生态学的研究具有重要的意义。

细菌群体在水生生态系统中起着重要的作用。本项目通过野外采样、高通量测序结合后续统计分析手段系统的研究了长江中游吞吐调蓄型湖泊的细菌群体组成的时空变化规律以及环境因子的驱动作用。研究结果表明两湖（鄱阳湖和洞庭湖）和长江的水样中富含变形杆菌门、放线菌门、拟杆菌门和厚壁菌门，变形杆菌是最丰富的门类。冗余分析结果表明水体中的有机碳和溶氧浓度是影响细菌群落组成的关键环境因子。邻近的采样点没有显示出相似的细菌群落组成，说明是环境因素而不是扩散限制影响了细菌的群落组成。本研究有利于更好的理解湖泊生态系统中细菌群落分布特征和形成机制，对湖泊细菌群体生态学的研究具有重要的意义。