Freshwater ecosystems are undergoing extensive human disturbance of dam construction which form large amounts of reservoirs and lead to dramatic changes in hydraulic conditions. Bacterioplankton are key component of aquatic ecosystems. Investigation on their taxonomic compositions and associated functions responded to reservoir operation is essential to understand the ecological consequence of dam construction. In this study, we use the Three Gorges Reservoir as a model system. High-throughput sequencing is used to investigate the bacterioplankton community composition, and the bioinformatic tool of Tax4Fun is applied to predict the potential metabolic functions responded to reservoir impoundment. Results show that the taxonomic communities of bacterioplankton are significantly impacted by impoundment. The dominant group of Actinobacteria which accounts for 17.0%-58.1% of the retrieved sequences significantly increases after impoundment on phylum level. The influences of impoundment appear to be more apparent on order level that the relative abundances of four groups including Frankiales, Sphingomonadales, Sphingobacteriales and SubsectionI of class Cyanobacteria significantly vary after impoundment. In contrast, the predicted functional communities of bacterioplankton remain relatively stable that most of predicted functional categories including methane and nitrogen metabolisms have no significant variation after impoundment. Besides, significant distance decay patterns appear on the taxonomic communities after impoundment rather than the predicted functional communities. The environmental variables show significant impacts on the taxonomic community rather than predicted functional community, whereas the spatial variables have no effect on both taxonomic and predicted functional communities. In general, the taxonomic and predicted functional communities of bacterioplankton exhibit divergent responses to the impoundment in reservoir.

中文翻译：

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浮游生物的分类学和预测功能分布对储层蓄水的不同反应。

淡水生态系统正遭受人类对大坝建设的广泛干扰，形成大量水库并导致水力状况发生急剧变化。浮游细菌是水生生态系统的关键组成部分。研究它们对水库运行的响应的分类学组成和相关功能对于了解大坝建设的生态后果至关重要。在这项研究中，我们使用三峡水库作为模型系统。高通量测序用于研究浮游细菌群落组成，Tax4Fun的生物信息学工具用于预测潜在的代谢功能，以应对水库蓄水。结果表明，蓄水对浮游细菌的分类群落有显着影响。蓄积在门上后，放线菌的优势群占所检索序列的17.0％-58.1％，显着增加。蓄积后，蓄水的影响似乎在阶数上更为明显，包括Frankiales，Sphingomonadales，Sphingobacteriales和蓝藻类I子区域的四个组的相对丰度显着变化。相比之下，浮游细菌的预测功能群落保持相对稳定，因此在封存后，包括甲烷和氮代谢在内的大多数预测功能类别均无显着变化。此外，蓄积后，分类群落上出现明显的距离衰减模式，而不是预测的功能群落。环境变量显示出对分类群落的显着影响，而不是预测的功能群落，而空间变量对分类和预测的功能群落均无影响。通常，浮游生物的分类学和预测功能群落对水库蓄水表现出不同的响应。