典农河冬季水体与沉积物细菌群落结构的差异特征及其影响因素

Structural differences and associated environmental factors of bacterial communities in water and sediment of Diannong River during winter

摘要:

目的 探究冬季河流生态系统中水体与沉积物细菌群落的结构差异及其影响因素。方法 以典农河为研究对象，冬季设置14个采样点，基于16S rRNA基因高通量测序技术系统分析细菌群落组成与多样性、构建共现网络、评估随机过程在群落组装中的作用，并进行环境因子相关性分析。结果 沉积物细菌群落的α多样性指数显著高于水体(P<0.001)，且其群落结构更稳定；β多样性分解表明两者的群落差异主要与物种周转相关；随机过程在两类群落构建中占主导地位；沉积物细菌群落的共现网络结构更复杂、协同性更强，关键物种主要参与碳、硫循环，稀有类群在网络稳定性中发挥重要作用；水体细菌群落主要受溶解氧(dissolved oxygen, DO)、叶绿素a (chlorophyll a, Chl-a)与水温(water temperature, WT)等因子调控，沉积物群落则受pH、有机质(soil organic matter, SOM)与氮素因子影响。结论 本研究系统揭示了冬季典农河水体与沉积物细菌群落在结构组成、共现网络以及相关环境因子方面的差异特征，为深入理解冰冻期河流细菌群落的生态适应性及水体与沉积物细菌群落的差异格局提供了科学依据。

Abstract:

Objective To explore the structural differences and associated environmental factors of bacterial communities in the water and sediment of river ecosystems during winter.Methods Fourteen sampling sites were established for Diannong River in winter. We employed high-throughput 16S rRNA gene sequencing to systematically analyze the bacterial community composition and diversity, constructed co-occurrence networks, and evaluated the roles of random processes in community assembly. Furthermore, we performed correlation analysis with environmental factors.Results The bacterial communities in the sediment had higher alpha diversity indexes than those in the water (P<0.001) and more stable community structures. The beta diversity decomposition showed that the community differences between water and sediment were mainly related to species turnover. Random processes dominated community assembly in both habitats. The co-occurrence network of bacteria in the sediment was more complex with stronger cooperation. Key species were primarily involved in carbon and sulfur cycles, and rare taxa played an important role in network stability. The bacterial communities in water were mainly influenced by environmental factors such as dissolved oxygen, chlorophyll a, and water temperature, while those in the sediment were influenced by pH, organic matter, and nitrogen factors.Conclusion This study systematically reveals the differences in the structure, co-occurrence network, and related environmental factors of bacterial communities in the water and sediment of Diannong River during winter, providing scientific evidence for a deeper understanding of the ecological adaptability of river bacterial communities in the freezing period and the different patterns of bacterial communities between water and sediment.