Xie Guijuan, Sun Chuanbo, Gong Yi, Luo Wenlei, Tang Xiangming
College of Biology and Pharmaceutical Engineering, West Anhui University, Lu'an, 237012, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
Microb Ecol. 2024 Jul 24;87(1):96. doi: 10.1007/s00248-024-02410-2.
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.
在营养水平较低的水生生态系统中，有机聚集体（OAs）充当营养热点，与水柱中的微生物物种相比，这里栖息着种类更为多样的微生物。以蓝藻水华加剧和延长为特征的湖泊富营养化，对物质和能量循环过程产生重大影响，可能改变自由生活（FL）细菌和附着于颗粒的（PA）细菌的生态特征。然而，关于观察到的FL和PA细菌多样性、群落组装及稳定性模式在超富营养湖泊中的延伸程度，仍有待深入研究。为填补这一空白，我们调查了超富营养星云湖内的细菌多样性、组成、组装过程及稳定性。我们的结果显示，FL细菌群落的α多样性高于PA细菌群落，且具有明显可辨的分类组成。两个细菌群落均呈现出明显的季节性，受蓝藻水华强度影响。环境因素分别解释了FL细菌和PA细菌变异的71.1%和54.2%。PA细菌群落的组装主要是随机的，而FL细菌的组装则更具确定性。FL网络表现出更高的稳定性、复杂性和负相互作用，表明存在竞争关系，而PA网络则以正相关为主，表明存在互利共生关系。重要的是，这些发现与贫营养、中营养和富营养湖泊中的观察结果不同。总体而言，本研究为细菌组分之间的相互作用提供了有价值的见解，增进了我们对营养状况和蓝藻水华在塑造细菌群落过程中作用的理解。
