| 长江流域河流和湖库的浮游细菌群落差异 |
| 摘要点击 1812 全文点击 553 投稿时间：2021-06-22 修订日期：2021-08-02 |
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| 中文关键词 长江流域 浮游细菌 宏条形码 单分子实时测序 16S rRNA |
| 英文关键词 Yangtze River basin bacterioplankton metabarcoding single molecule real-time sequencing 16S rRNA |
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| 中文摘要 |
| 在长江流域自江源区至入海口的干流重点区域、八大一级支流和多个重点湖库设置了177个样点开展浮游细菌调查，采用基于细菌16S rRNA基因的单分子实时测序技术研究浮游细菌群落的空间分布差异，期望在更广的调查范围和更高的物种注释精度上阐明长江流域浮游细菌群落结构的分布特征.首先分析了各采样点浮游细菌的α多样性状况，发现长江流域河流区域具有更高的物种丰富度，在多样性上与湖库区域差异显著.在此基础上开展了长江流域各采样点的β多样性分析，发现长江流域河流区域和湖库区域的浮游细菌群落组成差异显著，其中温度是河流浮游细菌群落分布的最大影响因素，湖库的pH是浮游细菌群落分布的最大影响因素.为探究河流区域和湖库区域浮游细菌群落结构差异在生态环境上的影响，在物种差异、功能差异和群落结构差异上开展了进一步研究.结果表明，对于河流区域而言，长江干流自西向东营养盐水平逐渐升高导致了部分物种相对丰度的逐渐增加；而湖库较河流有更高的蓝藻水华暴发风险，其中条件致病菌不动杆菌属在丹江口水库（南水北调水源区）具有较高相对丰度，存在着一定的生态风险，需要加强关注.物种组成上，河流区域和湖库区域绝大多数的物种（84%的OTU）为共有物种，同时两个区域均含有一些相对丰度较高但无法培养的细菌，因此仍需对长江流域作进一步的调查研究.综上所述，长江流域河流区域和湖库区域的浮游细菌存在着多样性、群落组成和富集物种的差异，这使得影响长江流域河流和湖库浮游细菌群落的最关键水质指标是不同的，同时也造成了二者在生态功能上的显著差异. |
| 英文摘要 |
| To explore the bacterioplankton community structure in the Yangtze River basin, water samples were collected from 177 sampling sites, including the source to the estuary along the mainstream of the Yangtze River, eight primary tributaries, and several lakes and reservoirs. The 16S rRNA genes were used to explore the bacterioplankton communities based on single molecule real-time sequencing, with the aim to study the diversity and community characteristics in a border sampling area and higher species annotation accuracy. Based on α-diversity analysis, the river area had higher species richness than that of the lake/reservoir area, resulting in these two areas having different bacterioplankton community diversities. Based on the β diversity analysis, the bacterioplankton showed different community compositions between the river and lake/reservoir areas; temperature was the key environmental factor for the river area, and pH was the key environmental factor for the lake/reservoir area. In order to study the influence of different bacterioplankton communities, this study further investigated the species, function, and community differences between the river and lake/reservoir areas. The results were as follows:for the river area, the eutrophication level gradually increased from west to east along the mainstream of the Yangtze River, resulting in a gradually increased relative abundance of specific species. The lake/reservoir area had a higher risk of cyanobacteria bloom, and the opportunistic pathogen had a high relative abundance in the Danjiangkou Reservoir, indicating a higher ecological risk. For species composition, the river and lake/reservoir areas shared most OTUs (84%); however, some uncultured bacteria showed a high relative abundance in the Yangtze River, meaning the bacterioplankton of the Yangtze River basin still requires further study. In general, the river and lake/reservoir shared most species; however, the different bacterioplankton diversity, community composition, and enriched species made the river and lake/reservoir have different key environmental factors, and they also showed differences in ecological functions. |
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