Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China.
Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China.
Sci Total Environ. 2019 Sep 10;682:324-332. doi: 10.1016/j.scitotenv.2019.05.172. Epub 2019 May 16.
Anthropogenic activities can cause serious negative effects on ecosystems. Despite the ecological significance of bacterial communities, the integrated biogeography of planktonic and sedimentary bacterial communities in response to anthropogenic activities is not adequately understood. Here, we examined environmental parameters and the composition of planktonic and sedimentary bacteria in the Yulin River, a tributary of Three Gorges Reservoir, in response to changes in land use and dam construction. The results revealed that human-induced land use changes enhanced the nutrient concentrations in surface water and dam construction reduced the content of carbon and nitrogen in immediately downstream sediments. Intensified human-dominated land use showed a slight impact on sedimentary bacterial communities but largely reduced the diversity of planktonic bacterial communities. Moreover, human-induced land use changes increased the abundance of genes associated with denitrification, nitrification, and anammox in planktonic bacterial communities by 19.04%, 32.40% and 30.45%, respectively. In dam construction regions, the diversity and nutrient-related metabolic activity of sedimentary bacterial communities immediately downstream of the dam were decreased, whereas these changes were not observed in planktonic bacterial communities. Additionally, bacterial community composition was significantly related to nutrient concentrations variability and followed a distance-decay pattern. Furthermore, environmental effects explained more of the variation in planktonic bacterial community composition as compared with spatial effects did, whereas, sedimentary bacterial communities were more closely related to spatial effects. Our results demonstrated the distinct responses of planktonic and sedimentary bacterial communities to anthropogenic activities, and offered new insight for understanding their potential ecological influence on rivers.
人为活动会对生态系统造成严重的负面影响。尽管细菌群落具有重要的生态意义，但对于浮游生物和底栖细菌群落对人为活动的综合生物地理学响应还了解不足。在这里，我们研究了受土地利用变化和大坝建设影响的三峡水库支流榆林河的浮游生物和底栖细菌的环境参数和组成。结果表明，人为引起的土地利用变化增加了地表水的养分浓度，而大坝建设减少了下游沉积物中碳和氮的含量。强化的以人为主导的土地利用对底栖细菌群落的影响较小，但大大降低了浮游细菌群落的多样性。此外，人为引起的土地利用变化使浮游细菌群落中与反硝化、硝化和厌氧氨氧化相关的基因丰度分别增加了 19.04%、32.40%和 30.45%。在大坝建设区，大坝下游沉积物中细菌群落的多样性和与养分相关的代谢活性下降，而浮游细菌群落中则没有观察到这些变化。此外，细菌群落组成与养分浓度变化显著相关，并遵循距离衰减模式。此外，与空间效应相比，环境效应能更好地解释浮游细菌群落组成的变化，而底栖细菌群落则与空间效应更为密切相关。我们的研究结果表明浮游生物和底栖细菌群落对人为活动有明显的响应，为了解它们对河流的潜在生态影响提供了新的认识。
