在营养水平低的水生生态系统中,有机聚集体(OAs)充当营养热点,与水柱中的微生物相比,它们拥有各种各样的微生物物种。湖泊富营养化,以加剧和延长的蓝藻水华为标志,显著影响材料和能量循环过程,可能会改变自由生活(FL)和颗粒附着(PA)细菌的生态特征。然而,观察到的FL和PA细菌多样性模式的程度,社区集会,以及对过度富营养化湖泊的稳定性仍未得到充分研究。为了解决这个差距,我们调查了细菌的多样性,composition,装配过程,和过富营养化的星云湖内的稳定性。我们的结果表明,FL细菌群落表现出比PA对应物更高的α-多样性,加上可辨别的分类组成。两种细菌群落都表现出明显的季节性,受蓝藻水华强度的影响。环境因子占FL和PA细菌变异的71.1%和54.2%,分别。PA细菌群落的组装主要是随机的,而FL装配更具确定性。FL网络表现出更大的稳定性,复杂性,和消极的互动,指示竞争关系,虽然PA网络显示出正相关的普遍性,暗示互惠互动。重要的是,这些发现与贫营养的观察结果不同,中营养,和富营养化的湖泊。总的来说,这项研究为细菌组分之间的相互作用提供了有价值的见解,加强我们对营养状况和蓝藻水华形成细菌群落的理解。
In aquatic ecosystems with low nutrient levels, organic aggregates (OAs) act as nutrient hotspots, hosting a diverse range of microbial species compared to those in the water column. Lake eutrophication, marked by intensified and prolonged cyanobacterial blooms, significantly impacts material and energy cycling processes, potentially altering the ecological traits of both free-living (FL) and particle-attached (PA) bacteria. However, the extent to which observed patterns of FL and PA bacterial diversity, community assembly, and stability extend to hypereutrophic lakes remains understudied. To address this gap, we investigated bacterial diversity, composition, assembly processes, and stability within hypereutrophic Lake Xingyun. Our results revealed that FL bacterial communities exhibited higher α-diversity than PA counterparts, coupled with discernible taxonomic compositions. Both bacterial communities showed distinct seasonality, influenced by cyanobacterial bloom intensity. Environmental factors accounted for 71.1% and 54.2% of the variation among FL and PA bacteria, respectively. The assembly of the PA bacterial community was predominantly stochastic, while FL assembly was more deterministic. The FL network demonstrated greater stability, complexity, and negative interactions, indicative of competitive relationships, while the PA network showed a prevalence of positive correlations, suggesting mutualistic interactions. Importantly, these findings differ from observations in oligotrophic, mesotrophic, and eutrophic lakes. Overall, this research provides valuable insights into the interplay among bacterial fractions, enhancing our understanding of nutrient status and cyanobacterial blooms in shaping bacterial communities.