AUTHOR=Gu Yabing , Meng Delong , Liu Zhenghua , Zhang Min , Yang Zhaoyue , Yin Huaqun , Liang Yanjie , Xiao Nengwen 

TITLE=Biotic and abiotic properties mediating sediment microbial diversity and function in a river–lake continuum

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1479670

DOI=10.3389/fmicb.2024.1479670

ISSN=1664-302X

ABSTRACT=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 environment. In this study, we analyzed the significant difference on sediment bacterial and fungal community structures and diversity indexes among Dongting Lake and its tributary rivers, which worked as a typical river-connected lake ecosystem. There were significant differences of biotic and abiotic environments in sediment habitats of Dongting Lake and its tributary rivers. Random forest analysis revealed that pH and Mollusca were found to be the most important abiotic and biotic variable 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, and more than half number of OTUs in each section were unique. Especially, the biotic and abiotic factors affected the number and the relative abundance of bacterial and fungal unique OTUs, and resulted in the changes of community composition. Mollusca, pH, TP, NO3-N and NH4-N were negatively related to the relative abundance of Actinobacteria, Acidobacteria, Gemmatimonadetes, Planctomycetes, and Ascomycota, while Annelida and ORP were positively related to the relative abundance of Actinobacteria and Gemmatimonadetes. Additionally, PICRUSt analysis revealed that the functional dissimilarity among lake and rivers were strengthened in unique species compared to all species in bacterial and fungal communities, and the changes of functional types helped to improve habitat environment in 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 river-lake ecosystem.