Gu Yabing, Meng Delong, Liu Zhenghua, Zhang Min, Yang Zhaoyue, Yin Huaqun, Liang Yanjie, Xiao Nengwen
School of Metallurgy and Environment, Central South University, Changsha, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China.
Front Microbiol. 2024 Oct 21;15:1479670. doi: 10.3389/fmicb.2024.1479670. eCollection 2024.
A river-lake system plays an important role in water management by providing long-term and frequent water diversions. However, hydrological connectivity in the system can have a profound effect on sediment microbial communities through pH, nutrient concentrations, and benthos invertebrates. Consequently, identifying the key environmental factors and their driving mechanisms is vital for microbial adaptation strategies to extreme environments. In this study, we analyzed the significant difference in sediment bacterial and fungal community structures and diversity indices among Dongting Lake and its tributary rivers, which worked as a typical river-connected lake ecosystem. There were significant differences in biotic and abiotic environments in the sediment habitats of Dongting Lake and its tributary rivers. Random forest analysis revealed that pH and were found to be the most important abiotic and biotic variables for predicting both bacterial and fungal community structures, respectively. The beta diversity decomposition analyses showed that the bacterial and fungal community compositional dissimilarities among different sections were dominated by species replacement processes, with more than half of the OTUs in each section being unique. Notably, both biotic and abiotic factors affected the number and the relative abundance of these bacterial and fungal unique OTUs, leading to changes in community composition. , pH, TP, NO-N, and NH-N were negatively related to the relative abundance of , and , while and ORP were positively related to the relative abundance of and . Additionally, PICRUSt analysis revealed that the functional dissimilarity among lakes and rivers was strengthened in unique species compared to all species in bacterial and fungal communities, and the changes of functional types helped to improve the habitat environment in the main Dongting Lake and promote the process of microbial growth. From our results, the role of macrozoobenthos and physicochemical characteristics in driving the sediment microbial community spatial variations became clear, which contributed to further understanding of the river-lake ecosystem.
河湖系统通过提供长期且频繁的调水，在水资源管理中发挥着重要作用。然而，该系统中的水文连通性可通过pH值、养分浓度和底栖无脊椎动物，对沉积物微生物群落产生深远影响。因此，识别关键环境因素及其驱动机制对于微生物适应极端环境的策略至关重要。在本研究中，我们分析了作为典型的河连湖生态系统的洞庭湖及其支流沉积物中细菌和真菌群落结构及多样性指数的显著差异。洞庭湖及其支流沉积物栖息地的生物和非生物环境存在显著差异。随机森林分析表明，pH值和分别被发现是预测细菌和真菌群落结构最重要的非生物和生物变量。β多样性分解分析表明，不同断面间细菌和真菌群落组成的差异主要由物种替代过程主导，每个断面超过一半的操作分类单元（OTU）是独特的。值得注意的是，生物和非生物因素均影响这些细菌和真菌独特OTU的数量和相对丰度，导致群落组成发生变化。 ，pH值、总磷（TP）、硝态氮（NO-N）和氨态氮（NH-N）与 、 的相对丰度呈负相关，而 和氧化还原电位（ORP）与 、 的相对丰度呈正相关。此外，PICRUSt分析表明，与细菌和真菌群落中的所有物种相比，湖泊和河流之间在独特物种中的功能差异得到加强，功能类型的变化有助于改善洞庭湖主体的栖息地环境并促进微生物生长过程。从我们的结果来看，大型底栖动物和理化特征在驱动沉积物微生物群落空间变异中的作用变得清晰，这有助于进一步理解河湖生态系统。
