Bingxian Xu, Yujiao Shi, Wenbao Li, Hengshuai Gao
State Key Laboratory of Water Engineering Ecology and Environment in Arid Area, Inner Mongolia Agricultural University, Hohhot, China.
Inner Mongolia Wild Scientific Observatory on the Ecological Environment of the Dali-nor Lake, Chifeng, China.
Front Microbiol. 2025 Jul 23;16:1623773. doi: 10.3389/fmicb.2025.1623773. eCollection 2025.
Bacteria serve as vital indicators of the lake ecosystem health. Although substantial progress has been made in investigating the structural features of lake bacterial communities, limited attention has been paid to the dynamic assembly processes and driving factors affecting bacterial communities in ice and water environments during the freeze-up period. In this study, we investigated aggregation and compositional changes in bacterial communities in the internal ice-covered state of Lake Hulun. We examined the effects of cryoconcentration under low-temperature conditions on community assembly and systematically analyzed the physicochemical parameters as well as α- and β-diversity of bacterial communities in bottom ice (BI) and surface water (SW) media. Bacterial diversity was significantly higher in SW than in BI. Among the dominant taxa, eight phyla were shared between both environments. Firmicutes and Patescibacteria were dominant in the BI, whereas Gemmatimonadota and Bdellovibrionota were dominant in the SW. Nutrient transport driven by cryoconcentration emerged as a key factor influencing bacterial community assembly. Specifically, total nitrogen and salinity regulated the balance between stochastic and deterministic processes in BI and SW, respectively. Overall, the distinct environmental conditions of BI and SW weakened the diffusion capacity of bacterial communities, resulting in diffusion-limited and drift-dominated assembly processes. These findings offer new insights into the mechanisms underlying bacterial interactions and community assembly in ice-covered lake habitats and provide a scientific foundation for the management and preservation of lake ecosystems under ice-covered conditions.
细菌是湖泊生态系统健康的重要指标。尽管在研究湖泊细菌群落的结构特征方面取得了重大进展，但在冰封期，对于影响冰和水环境中细菌群落的动态组装过程及驱动因素的关注却十分有限。在本研究中，我们调查了呼伦湖内部冰封状态下细菌群落的聚集和组成变化。我们研究了低温条件下的冷冻浓缩对群落组装的影响，并系统分析了底冰（BI）和地表水（SW）介质中细菌群落的理化参数以及α-和β-多样性。SW中的细菌多样性显著高于BI。在优势类群中，两个环境共有8个门。厚壁菌门和Patescibacteria在BI中占主导地位，而芽单胞菌门和蛭弧菌门在SW中占主导地位。由冷冻浓缩驱动的营养物质运输成为影响细菌群落组装的关键因素。具体而言，总氮和盐度分别调节了BI和SW中随机过程和确定性过程之间的平衡。总体而言，BI和SW截然不同的环境条件削弱了细菌群落的扩散能力，导致了扩散受限和以漂变为主的组装过程。这些发现为冰封湖泊栖息地中细菌相互作用和群落组装的潜在机制提供了新的见解，并为冰封条件下湖泊生态系统的管理和保护提供了科学依据。
