Biotic and abiotic properties mediating sediment microbial diversity and function in a river-lake continuum

Area of Science:

• Environmental microbiology
• Aquatic ecology
• Ecosystem science

Background:

• River-lake systems are crucial for water management and hydrological connectivity influences sediment microbial communities.
• Environmental factors (pH, nutrients) and biotic components (invertebrates) profoundly impact microbial life.
• Identifying key drivers is essential for understanding microbial adaptation in extreme aquatic environments.

Purpose of the Study:

• To analyze differences in sediment bacterial and fungal community structures and diversity between Dongting Lake and its tributary rivers.
• To identify key abiotic and biotic factors influencing these microbial communities.
• To elucidate the mechanisms driving microbial community variations in a river-connected lake ecosystem.

Main Methods:

• Comparative analysis of sediment bacterial and fungal communities in Dongting Lake and tributary rivers.
• Random forest analysis to determine the importance of environmental variables.
• Beta diversity decomposition and PICRUSt analysis to assess community structure and function.

Main Results:

• Significant differences in sediment microbial community structures and diversity were observed between the lake and river habitats.
• pH and Mollusca were identified as the most critical abiotic and biotic factors, respectively, shaping community composition.
• Species replacement was the primary driver of beta diversity, with unique operational taxonomic units (OTUs) influenced by both biotic and abiotic factors.

Conclusions:

• Physicochemical characteristics and macrozoobenthos play a significant role in driving spatial variations of sediment microbial communities.
• Unique microbial taxa and their associated functions contribute to habitat adaptation and ecosystem processes in river-lake systems.
• This study enhances the understanding of ecological dynamics within river-connected lake ecosystems.