Zhou Lei, Chen Weiyuan, Sun Jijia, Liu Li, Huang Xiande
Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China.
Microorganisms. 2020 May 29;8(6):814. doi: 10.3390/microorganisms8060814.
River ecosystems are critical for human and environmental health, with bacterioplankton playing a vital role in biogeochemical cycles. Unveiling the spatial patterns of bacterioplankton communities in relation to environmental factors is important for understanding the processes of microbial variation and functional maintenance. However, our understanding of the correlations among bacterioplankton communities, physicochemical factors, and land use, especially in large rivers affected by intensive anthropogenic activities, remains relatively poor. Here, we investigated the bacterioplankton communities in July 2018 in three main tributaries of the Pearl River, i.e., Beijiang, Xijiang, and Pearl River Delta, based on 16S rRNA high-throughput sequencing. Results showed that the most dominant phyla, Proteobacteria, Actinobacteria, Cyanobacteria, and Planctomycetes accounted for 33.75%, 22.15%, 11.65%, and 10.48% of the total abundance, respectively. The bacterioplankton communities showed remarkable differences among the three tributaries in terms of composition, structure, diversity, and predictive functional profiles. Mantel and partial Mantel tests revealed that the bacterioplankton communities were affected by physicochemical variables ( < 0.01) and land use ( < 0.01). Redundancy analysis identified specific conductivity, dissolved oxygen, agricultural land, ammonium, urban land, and water transparency as the dominant environmental factors influencing the bacterioplankton communities in the Pearl River. Variation partitioning analysis indicated that both physicochemical factors and land use had direct effects on the bacterioplankton community, and that land use may also shape bacterioplankton communities through indirect effects of physicochemical factors on riverine ecosystems. This study provides fundamental information on the diversity, spatial patterns, and influencing factors of bacterioplankton communities in the Pearl River, which should enhance our understanding of how such communities change in response to environmental gradients and anthropogenic activities.
河流生态系统对人类健康和环境健康至关重要，其中浮游细菌在生物地球化学循环中发挥着关键作用。揭示浮游细菌群落与环境因素相关的空间格局，对于理解微生物变异和功能维持过程具有重要意义。然而，我们对浮游细菌群落、理化因素和土地利用之间的相关性的理解仍然相对不足，尤其是在受密集人为活动影响的大型河流中。在此，我们基于16S rRNA高通量测序，于2018年7月对珠江的三条主要支流，即北江、西江和珠江三角洲的浮游细菌群落进行了调查。结果表明，最主要的门类，变形菌门、放线菌门、蓝细菌门和浮霉菌门分别占总丰度的33.75%、22.15%、11.65%和10.48%。浮游细菌群落在三条支流之间的组成、结构、多样性和预测功能概况方面表现出显著差异。Mantel检验和偏Mantel检验表明，浮游细菌群落受理化变量（<0.01）和土地利用（<0.01）的影响。冗余分析确定电导率、溶解氧、农业用地、铵、城市用地和水体透明度是影响珠江浮游细菌群落的主要环境因素。变异分解分析表明，理化因素和土地利用对浮游细菌群落都有直接影响，并且土地利用也可能通过理化因素对河流生态系统的间接影响来塑造浮游细菌群落。本研究提供了珠江浮游细菌群落的多样性、空间格局和影响因素的基础信息，这将增进我们对这些群落如何响应环境梯度和人为活动而变化的理解。
