Bacterial community composition shaped by water chemistry and geographic distance in an anthropogenically disturbed river.
Bacterial community composition shaped by water chemistry and geographic distance in an anthropogenically disturbed river.
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DOI：
10.1016/j.scitotenv.2018.11.234
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
Peng Wang;Jun Zhao;Hanyu Xiao;Wenjing Yang;Xiaofang Yu
中科院分区：
文献类型：
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作者：
Peng Wang;Jun Zhao;Hanyu Xiao;Wenjing Yang;Xiaofang Yu
“核心细菌群落”，即在整个河流连续体中一致发现的细菌物种，以前已经被确定。然而，核心和非核心细菌群落结构的变化，以及这些社区和水化学或地理距离之间的关系还没有得到很好的研究。在这里，我们在中国乐安河的整个过程中取样，并使用Illumina高通量测序探索每个站点的细菌群落组成。在上游和中游，分配给核心群落的序列读段比例约为95%，在下游逐渐降至90%以下。细菌群落的Chao 1丰富度指数和Shannon多样性指数在丰水期均显著高于枯水期，且从上游到下游略有增加。非核心群落在丰水期比枯水期从上游到下游的聚集性更强，而核心群落在枯水期和丰水期的聚集性相似。核心群落中典型淡水细菌的比例显著高于非核心群落。NO3−-N是最能解释细菌群落差异的水化学参数的子集，而“河流长度”是最能解释细菌群落差异的地理距离参数的子集。水化学参数解释了更多的细菌群落的变化比地理距离，特别是在旱季。然而，水化学和细菌之间的相关性主要是由于集体异地输入（质量效应），而不是因为任何营养或毒性的细菌生长竞争（物种分选）的影响。与物种分选相比，质量效应对细菌群落结构的影响更大，这是由于人为来源的细菌的外来输入。
‘Core bacterial communities’, bacterial species that are found consistently throughout a river continuum, have previously been identified. However, variations in core and non-core bacterial community structure, as well as the relationships between these communities and water chemistry or geographic distance have not been well studied. Here, we sampled in the entire course of the Le'an River, China, and explored the bacterial community composition at each site using Illumina high-throughput sequencing. The proportion of sequence reads assigned to the core community was ~95% in the upper and middle reaches, gradually decreasing below 90% in the lower reaches. Both the Chao1 richness index and the Shannon diversity index of the bacterial communities were significantly higher in the wet season than in the dry season, and both indices increased slightly from upstream to downstream. The variation in the non-core community was more aggregated from upstream to downstream in the wet season than in the dry season, while the aggregation of the core community was similar between the dry season and the wet season. The proportion of typical freshwater bacterial was significantly higher in the core community than in the non-core community. NO3−-N was the subset of water chemistry parameters that best explained bacterial community dissimilarities, while ‘river length’ was the subset of geographic distance parameters that best explained bacterial community dissimilarities. Water chemistry parameters explained more of the variations in the bacterial communities than did geographic distance, especially in the dry season. However, the correlation between water chemistry and bacteria was primarily due to collective allochthonous input (mass effects), not because of any nutritious or toxic effects on bacterial growth competition (species sorting). The greater influence of the mass effects, as compared to species sorting, on bacterial community structure was due to the allochthonous input of bacteria from anthropogenic sources.