贫营养深水湖泊是独特而敏感的生态系统,养分供应有限。了解这些湖泊中的细菌群落对于评估生态系统健康至关重要。生物地球化学循环,以及对环境变化的反应。在这项研究中,我们调查了抚仙湖自由生活(FL)和颗粒附着(PA)细菌的季节和垂直动态,中国东南部典型的贫营养深层淡水湖。我们的发现揭示了FL和PA细菌群落的不同季节和垂直动态,由相似的理化环境因素驱动。PA细菌表现出较高的α-和β-多样性,并富集了变形杆菌,蓝细菌,Firmicutes,芽孢杆菌,Planctomycetota,和Verrucomicrobiota,而FL细菌富含放线菌和类杆菌。FL细菌显示出与化学异型和有氧缺氧光合作用相关的推定功能的富集,而PA部分富含细胞内寄生虫(主要由Rickettsiales贡献,衣原体,和军团菌)和氮代谢功能。确定性过程主要塑造了FL和PA细菌群落的组装,随机过程在FL分数中发挥更大的作用。网络分析揭示了广泛的物种相互作用,PA网络中正相关边的比例较高,表示互惠或合作的互动。氰,Comamonadaceae,玫瑰单胞菌被确定为PA网络中的梯形分类群,强调有机颗粒微生境中自养和异养细菌之间的潜在合作。总的来说,细菌多样性的差异,社区组成,假定函数,FL和PA组分之间的网络特征突出了它们对这些独特湖泊生态系统中不同生态位的适应。重要了解微生物群落的多样性,他们的组装机制,它们对环境变化的反应是研究水生微生物生态学的基础。贫营养型深水湖泊是脆弱的生态系统,营养资源有限,使它们极易受到环境波动的影响。检查这些湖泊中的不同细菌类型可以为管理各种规模的社区动态和适应策略的复杂机制提供宝贵的见解。在我们对中国富县贫营养深层淡水湖的调查中,我们探索了两种细菌类型的季节和垂直动态:自由生活(FL)和颗粒附着(PA)。我们的发现揭示了多样性的不同模式,composition,这些细菌的功能,都是由环境因素塑造的。了解这些微妙之处提供了对细菌相互作用的见解,从而影响整个生态系统的功能。最终,我们的研究阐明了FL和PA细菌在这些独特的湖泊环境中的适应和作用,大大有助于我们更广泛地理解生态系统的稳定性和健康。
Oligotrophic deep-water lakes are unique and sensitive ecosystems with limited nutrient availability. Understanding bacterial communities within these lakes is crucial for assessing ecosystem health, biogeochemical cycling, and responses to environmental changes. In this study, we investigated the seasonal and vertical dynamics of both free-living (FL) and particle-attached (PA) bacteria in Lake Fuxian, a typical oligotrophic deep freshwater lake in southeast China. Our findings revealed distinct seasonal and vertical dynamics of FL and PA bacterial communities, driven by similar physiochemical environmental factors. PA bacteria exhibited higher α- and β-diversity and were enriched with Proteobacteria, Cyanobacteria, Firmicutes, Patescibacteria, Planctomycetota, and Verrucomicrobiota, while FL bacteria were enriched with Actinobacteria and Bacteroidota. FL bacteria showed enrichment in putative functions related to chemoheterotrophy and aerobic anoxygenic photosynthesis, whereas the PA fraction was enriched with intracellular parasites (mainly contributed by Rickettsiales, Chlamydiales, and Legionellales) and nitrogen metabolism functions. Deterministic processes predominantly shaped the assembly of both FL and PA bacterial communities, with stochastic processes playing a greater role in the FL fraction. Network analysis revealed extensive species interactions, with a higher proportion of positively correlated edges in the PA network, indicating mutualistic or cooperative interactions. Cyanobium, Comamonadaceae, and Roseomonas were identified as keystone taxa in the PA network, underscoring potential cooperation between autotrophic and heterotrophic bacteria in organic particle microhabitats. Overall, the disparities in bacterial diversity, community composition, putative function, and network characteristics between FL and PA fractions highlight their adaptation to distinct ecological niches within these unique lake ecosystems.IMPORTANCEUnderstanding the diversity of microbial communities, their assembly mechanisms, and their responses to environmental changes is fundamental to the study of aquatic microbial ecology. Oligotrophic deep-water lakes are fragile ecosystems with limited nutrient resources, rendering them highly susceptible to environmental fluctuations. Examining different bacterial types within these lakes offers valuable insights into the intricate mechanisms governing community dynamics and adaptation strategies across various scales. In our investigation of oligotrophic deep freshwater Lake Fuxian in China, we explored the seasonal and vertical dynamics of two bacterial types: free-living (FL) and particle-attached (PA). Our findings unveiled distinct patterns in the diversity, composition, and putative functions of these bacteria, all shaped by environmental factors. Understanding these subtleties provides insight into bacterial interactions, thereby influencing the overall ecosystem functioning. Ultimately, our research illuminates the adaptation and roles of FL and PA bacteria within these unique lake environments, contributing significantly to our broader comprehension of ecosystem stability and health.