Distinct Assembly Mechanisms Underlie Similar Biogeographic Patterns of Rare and Abundant Bacterioplankton in Cascade Reservoirs of a Large River
Distinct Assembly Mechanisms Underlie Similar Biogeographic Patterns of Rare and Abundant Bacterioplankton in Cascade Reservoirs of a Large River
复制标题
大河梯级水库中稀有和丰富的浮游细菌具有相似的生物地理模式，其组装机制不同
DOI：
10.3389/fmicb.2020.00158
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发表时间：
2020-02-07
影响因子：
5.2
通讯作者：
Sun, Shenghao
中科院分区：
文献类型：
--
作者：
Chen, Juan;Wang, Peifang;Sun, Shenghao
浮游细菌群落一般由少数高度丰富的物种和大量在水生生态系统的生物地球化学循环中起关键作用的稀有物种组成。然而，人们对这些群落的生物地理集合知之甚少，特别是在遭受梯级大坝治理的大河流中。本文采用16S rRNA基因扩增片段测序的方法，研究了中国金沙江梯级水库浮游细菌群落的生物地理格局和稀有浮游细菌群落的组装机制。结果表明，由于大坝的修建，浮游细菌的物种减少，对稀有类群的损失比对丰富类群的损失更大。丰度类群和稀有类群的分布具有相似的时空格局，冬季和夏季以及上下游水库之间的分布差异显著。空间(与扩散相关的过程)和环境(选择过程)似乎共同控制着丰富和稀有类群的组装和生物地理，尽管这两个因素只解释了稀有类群的一小部分变异。更重要的是，环境因子对丰富子群落的群落变异的解释大于对稀有子群落的解释。共生网络分析表明，与稀有物种相比，相互作用更密切的物种更多地处于网络的中心位置。然而，有一半的Keystone物种是稀有物种，可能在维持网络稳定方面发挥重要作用。总体而言，这些发现表明，在一条大河的梯级水库中，稀有和丰富的细菌的相似生物地理基础上有不同的组装机制。
Bacterioplankton communities commonly consist of few highly abundant species and a large number of rare species that play key roles in biogeochemical cycles of aquatic ecosystems. However, little is known about the biogeographic assemblies of these communities, especially in large rivers suffering from cascade dam regulation. Here, we used a 16S rRNA gene amplicon sequencing approach to investigate the biogeographic patterns and underlying assembly mechanisms of abundant and rare bacterioplankton taxa in cascade reservoirs of the Jinsha River in China. The results revealed species loss of bacterioplankton due to dam construction, which was more significant for rare taxa than for abundant ones. The distributions of abundant and rare taxa exhibited similar spatial and temporal patterns, which were significantly distinct between winter and summer and between upstream and downstream reservoirs. Both spatial (dispersal-related process) and environmental (selection process) factors seemed to together govern the assembly and biogeography of abundant and rare taxa, although both factors explained only a small fraction of variation in the rare taxa. More importantly, environmental factors explained more community variation in abundant sub-community than that in rare sub-community. Co-occurrence network analysis revealed that abundant species with closer interactions were more often located in a central position of the network compared with rare species. Nevertheless, half of the keystone species were rare species and may play important roles in maintaining the network stability. Overall, these findings indicate that distinct assembly mechanisms underlie the similar biogeography of rare and abundant bacteria in cascade reservoirs of a large river.