Wang Xiaojie, Yin Yue, Yu Zhiqiang, Shen Guofeng, Cheng Hefa, Tao Shu
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China; MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Sci Total Environ. 2023 Mar 10;863:160832. doi: 10.1016/j.scitotenv.2022.160832. Epub 2022 Dec 12.
The diversity and distribution patterns of the abundant and rare microbial sub-communities in hot spring ecosystems and their assembly mechanisms are poorly understood. The present study investigated the diversity and distribution patterns of the total, abundant, conditionally rare, and always rare taxa in the low- and moderate-temperature hot spring sediments on the Tibetan Plateau based on high-throughput 16S rRNA gene sequencing, and explored their major environmental drivers. The diversity of these four bacterial taxa showed no significant change between the low-temperature and moderate-temperature hot spring sediments, whereas the bacterial compositions were obviously different. Stochasticity dominated the bacterial sub-community assemblages, while heterogeneous selection also played an important role in shaping the abundant and conditionally rare taxa between the low-temperature and moderate-temperature hot spring sediments. No significant difference in the topological properties of co-occurrence networks was found between the conditionally rare and abundant taxa, and the connections between the paired operational taxonomic units (OTUs) were almost positive. The diversity of the total, abundant, and conditionally rare taxa was governed by the salinity of hot spring sediments, while that of the always rare taxa was determined by the content of S element. In contrast, temperature had significant direct effect on the composition of the total, abundant, and conditionally rare taxa, but relatively weak influence on that of the always rare taxa. Besides, salinity was another major environmental factor driving the composition of the abundant and rare sub-communities in the hot spring sediments. These results reveal the assembly processes and major environmental drivers that shaped different bacterial sub-communities in the hot spring sediments on the Tibetan Plateau, and indicate the importance of conditionally rare taxa in constructing bacterial communities. These findings enhance the current understanding of the ecological mechanisms maintaining the ecosystem stability and services in extreme environment.
温泉生态系统中丰富和稀有微生物亚群落的多样性、分布模式及其组装机制目前仍知之甚少。本研究基于高通量16S rRNA基因测序，调查了青藏高原低温和中温温泉沉积物中总分类群、丰富分类群、条件稀有分类群和始终稀有分类群的多样性和分布模式，并探讨了它们的主要环境驱动因素。这四类细菌分类群的多样性在低温和中温温泉沉积物之间没有显著变化，而细菌组成明显不同。随机性在细菌亚群落组装中占主导地位，而异质性选择在塑造低温和中温温泉沉积物之间的丰富和条件稀有分类群方面也发挥了重要作用。条件稀有分类群和丰富分类群之间在共现网络的拓扑性质上没有显著差异，并且配对的操作分类单元（OTU）之间的连接几乎都是正的。总分类群、丰富分类群和条件稀有分类群的多样性受温泉沉积物盐度的控制，而始终稀有分类群的多样性则由硫元素含量决定。相比之下，温度对总分类群、丰富分类群和条件稀有分类群的组成有显著直接影响，但对始终稀有分类群的影响相对较弱。此外，盐度是驱动温泉沉积物中丰富和稀有亚群落组成的另一个主要环境因素。这些结果揭示了塑造青藏高原温泉沉积物中不同细菌亚群落的组装过程和主要环境驱动因素，并表明条件稀有分类群在构建细菌群落中的重要性。这些发现加深了我们目前对极端环境中维持生态系统稳定性和服务的生态机制的理解。
