Wang Wanping, Wang Rongxin, Li Yuying, Li Yixuan, Zhang Pengcheng, Gao Mingming, Cao Yuxuan, Fohrer Nicola, Zhang Yixin, Li B Larry
International Joint Laboratory of Watershed Ecological Security for Water Source Region of Middle Route Project of South-North Water Diversion in Henan Province, College of South to North Water Diversion / College of Water Resource and Modern Agriculture, Nanyang Normal University, Nanyang, 473061, China.
International Joint Laboratory of Watershed Ecological Security for Water Source Region of Middle Route Project of South-North Water Diversion in Henan Province, College of South to North Water Diversion / College of Water Resource and Modern Agriculture, Nanyang Normal University, Nanyang, 473061, China.
J Environ Manage. 2025 Apr;379:124851. doi: 10.1016/j.jenvman.2025.124851. Epub 2025 Mar 7.
Water depth variation can lead to the vertical structure change of microbial communities in reservoirs, and then affect the relationship between the microbial communities along the depth gradient, profoundly affecting the stability of the aquatic ecosystems. However, the interspecific dynamics of microbial communities across different water layers in deep-water low-nutrient drinking water reservoirs remain not well understood. Thus, we assessed microbial communities' dynamic changes in different water layers in this study. The physical and chemical parameters and different planktonic microbial of the surface, middle, and bottom layers were studied from July 2022 to August 2023 in the Danjiangkou Reservoir, China. Based on high-throughput sequencing technology, model analysis and network analysis, the diversity of microbial communities in different water layers, community construction process and co-occurrence network differences were studied. The results showed that the diversity of bacterial communities in the Danjiangkou reservoir was significantly higher than that of fungi and eukaryotic microorganisms in different water depths. The dominant taxa of the bacterial communities in different water depths were Actinobacteriota, Bacteroidota, Proteobacteria and Cyanobacteria. The dominant phyla were Ascomycota, unclassified_k__Fungi and Chytridiomycota. The relative abundance of vertical dominant species in eukaryotic communities was slightly different, including Cryptophyta, Chlorophyta, Dinophyta and Metazoa. Different microbial communities shared the main dominant species on the vertical stratification. The neutral model showed that random processes significantly affected the assembly process of microbial communities in different water layers, and the mobility of fungal communities was much lower than that of bacteria and eukaryotes. The co-occurrence network analysis showed that the number of nodes and edges of the bacterial community was the highest, indicating that the network scale of the bacterial community was the largest. In addition, the map density and average clustering coefficient of bacterial and eukaryotic communities in surface water were the highest, indicating that the surface microbial species had a high degree of connectivity, can better transfer materials and exchange information, and Sensitive to changes in the external environment. In contrast, in fungal communities, microbial interactions were the most complex at the bottom. The interactions between microbial communities in different water depths were mainly positive, and the negative correlation of microbial communities in the middle and bottom water was greater than that in the surface water, indicating that the competition between species increased with the increase of depth. Correlation analysis showed that the key species of microbial community were significantly correlated with TP, PO-P, NO-N and ORP. In summary, by analyzing water depth changes' impacts on the spatial distribution pattern, community assembly process and symbiotic network stability of microbial communities in the Danjiangkou Reservoir, we found that bacterial communities were more sensitive to water depth than eukaryotes and fungi. This study revealed the response mechanism of microbial communities to water depth in low-nutrient reservoirs, which is helpful to reflect aquatic ecological processes and provide a theoretical basis for the construction of subsequent reservoir ecological models.
水深变化会导致水库中微生物群落的垂直结构发生变化，进而影响沿深度梯度的微生物群落之间的关系，深刻影响水生生态系统的稳定性。然而，深水低营养饮用水水库中不同水层微生物群落的种间动态仍未得到充分了解。因此，在本研究中我们评估了不同水层中微生物群落的动态变化。2022年7月至2023年8月，对中国丹江口水库表层、中层和底层的理化参数及不同浮游微生物进行了研究。基于高通量测序技术、模型分析和网络分析，研究了不同水层微生物群落的多样性、群落构建过程和共现网络差异。结果表明，丹江口水库细菌群落的多样性显著高于不同水深的真菌和真核微生物。不同水深细菌群落的优势类群为放线菌门、拟杆菌门、变形菌门和蓝细菌门。优势菌纲为子囊菌纲、未分类的真菌纲和壶菌纲。真核生物群落中垂直优势物种的相对丰度略有不同，包括隐藻门、绿藻门、甲藻门和后生动物。不同微生物群落在垂直分层上共享主要优势物种。中性模型表明，随机过程显著影响不同水层微生物群落的组装过程，真菌群落的迁移率远低于细菌和真核生物。共现网络分析表明，细菌群落的节点数和边数最高，表明细菌群落的网络规模最大。此外，地表水细菌和真核生物群落的图谱密度和平均聚类系数最高，表明表层微生物物种具有高度的连通性，能够更好地传递物质和交换信息，并且对外部环境变化敏感。相比之下，在真菌群落中，底部微生物相互作用最为复杂。不同水深微生物群落之间的相互作用主要为正相关，中层和底层水微生物群落的负相关大于表层水，表明物种间竞争随深度增加而增加。相关性分析表明，微生物群落的关键物种与总磷、活性磷、硝态氮和氧化还原电位显著相关。综上所述，通过分析水深变化对丹江口水库微生物群落空间分布格局、群落组装过程和共生网络稳定性的影响，我们发现细菌群落比真核生物和真菌对水深更敏感。本研究揭示了低营养水库中微生物群落对水深的响应机制，有助于反映水生生态过程，为后续水库生态模型的构建提供理论依据。
