Yang Yang, Chen Chen, Grossart Hans-Peter, Liu Yingliang
School of life sciences, Guizhou Normal University, Guiyang 550025, China; Guizhou Key Laboratory of Forest Cultivation in Plateau Mountain, Guiyang 550025, China.
School of life sciences, Guizhou Normal University, Guiyang 550025, China.
Ecotoxicol Environ Saf. 2025 Jun 1;297:118262. doi: 10.1016/j.ecoenv.2025.118262. Epub 2025 May 3.
Bacterial communities are composed of a few abundant taxa (AT) and numerous rare taxa (RT). Rivers serve as connectors between water, sediment, and riparian soil, leading to differences in bacterial communities across these habitats. In this study, we sampled 26 sites along the Wujiang River, a major tributary of the Yangtze River in a karst region of China to systematically target the habitat-specific differences in bacterial communities. We hypothesized that (1) community composition and diversity differ among habitats; (2) AT and RT communities exhibit distinct biogeographic patterns; (3) the community assembly processes differ between AT and RT within and across habitat. Results showed significant differences in bacterial community composition between water and sediment, water and soil, but not between sediment and soil. Sediment and soil had higher species richness and diversity than water, with RT mainly contributing to diversity differences. β-diversity was primarily driven by species turnover. A distance-decay relationship appeared only in water communities, indicating stronger spatial structuring, while sediment and soil communities were mainly shaped by environmental factors. Assembly of AT in sediment and soil was governed by undominated processes (ecological drift), whereas dispersal limitation dominated in water. for RT, homogeneous dispersal prevailed in water, while homogeneous selection was predominant in sediment and soil. these findings advance our understanding of abundant and rare bacterial community assembly across riverine habitats and provide new insights into microbial biogeography in plateau karst aquatic ecosystems.
细菌群落由少数丰富类群（AT）和众多稀有类群（RT）组成。河流作为水、沉积物和河岸土壤之间的连接纽带，导致这些栖息地的细菌群落存在差异。在本研究中，我们在中国喀斯特地区长江的一条主要支流乌江沿线的26个地点进行采样，以系统地研究细菌群落的栖息地特异性差异。我们假设：（1）不同栖息地之间的群落组成和多样性存在差异；（2）丰富类群和稀有类群群落呈现出不同的生物地理模式；（3）丰富类群和稀有类群在栖息地内部和之间的群落组装过程存在差异。结果表明，水与沉积物、水与土壤之间的细菌群落组成存在显著差异，但沉积物与土壤之间没有差异。沉积物和土壤的物种丰富度和多样性高于水，稀有类群是多样性差异的主要贡献者。β多样性主要由物种更替驱动。距离衰减关系仅出现在水群落中，表明空间结构更强，而沉积物和土壤群落主要受环境因素影响。沉积物和土壤中丰富类群的组装由非主导过程（生态漂变）控制，而在水中扩散限制起主导作用。对于稀有类群，均匀扩散在水中占主导，而均匀选择在沉积物和土壤中占主导。这些发现增进了我们对河流栖息地中丰富和稀有细菌群落组装的理解，并为高原喀斯特水生生态系统中的微生物生物地理学提供了新的见解。
