School of Geography and Environment, Jiangxi Normal University, Nanchang 330022, Jiangxi, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Sino-Danish College of University of Chinese Academy of Sciences, Beijing 101408, China; Sino-Danish Centre for Education and Research, Beijing 101408, China.
School of Geography and Environment, Jiangxi Normal University, Nanchang 330022, Jiangxi, China; Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang 330022, Jiangxi, China.
Sci Total Environ. 2022 Mar 10;811:151350. doi: 10.1016/j.scitotenv.2021.151350. Epub 2021 Oct 30.
Bacterioplankton communities in rivers are strongly influenced by the surrounding landscape, yet the relationships between land use and bacterioplankton communities at multi-spatial scales and the mechanisms that shape bacterioplankton communities remain unclear. Here, we collected surface water samples from 14 tributaries of the Yuan River, a secondary tributary of the Yangtze River, which has been heavily impacted by human activities. We characterized the bacterioplankton communities by high-throughput sequencing techniques, and managed to identify the mechanisms governing bacterioplankton community assembly. The results showed that, in general, both landscape compositions and landscape configurations had significant effects on bacterial communities, and the effects were greater at the buffer scale than at the sub-basin scale. Additionally, there was no distinct distance-decay pattern for the effects of landscape structures on bacterial communities from the near-distance (100 m) to the long-distance (1000 m) buffer zones, with the maximal effects occurring in the 1000 m circular buffer (wet season) and 500 m riparian buffer (dry season) zone, respectively. Land use influenced the bacterioplankton community both directly through exogenous inputs (mass effect) and indirectly by affecting water chemistry (species sorting). Variance partitioning analyses showed that the total explanations of bacterial community variations by water chemistry and the intersections of water chemistry and land use (56.2% in wet season and 50.4% in dry season) were higher than that of land use alone (6.1% in wet season and 25.4% in dry season). These suggest that mass effects and species sorting jointly shaped bacterial community assembly, but that the effects of species sorting outweighed those of mass effects. Nevertheless, more biotic and abiotic factors need to be considered to better understand the microbial assembly mechanisms in anthropogenically influenced riverine ecosystems.
河流中的细菌浮游生物群落受周围景观的强烈影响，但土地利用与多空间尺度细菌浮游生物群落的关系以及塑造细菌浮游生物群落的机制仍不清楚。在这里，我们从长江二级支流沅江的 14 条支流收集了地表水样本，这些支流受到了人类活动的严重影响。我们通过高通量测序技术对细菌浮游生物群落进行了特征描述，并设法确定了控制细菌浮游生物群落组装的机制。结果表明，一般来说，景观组成和景观配置对细菌群落都有显著影响，而且在缓冲区尺度上的影响大于在子流域尺度上的影响。此外，景观结构对细菌群落的影响在近距（100m）到远距离（1000m）缓冲区之间没有明显的距离衰减模式，最大影响分别发生在 1000m 圆形缓冲区（湿季）和 500m 河岸缓冲区（干季）。土地利用通过外源输入（质量效应）和通过影响水化学（物种分选）间接影响细菌浮游生物群落，直接影响细菌浮游生物群落。方差分解分析表明，水化学和水化学与土地利用的交点对细菌群落变异的总解释（湿季为 56.2%，干季为 50.4%）高于土地利用的单独解释（湿季为 6.1%，干季为 25.4%）。这表明质量效应和物种分选共同塑造了细菌群落的组装，但物种分选的影响大于质量效应的影响。然而，需要考虑更多的生物和非生物因素，以更好地理解人为影响的河流生态系统中的微生物组装机制。
