Philippine E-Journals

Microbial Community Diversities Across Hyporheic Zones of Gravel Bars in a River: Taxonomic and Functional Distributions

Arnelyn D. Doloiras-larano | Maribet Gamboa | Shinji Takahashi | Joeselle M. Serrana | Yasuhiro Takemono | Paul R. Johnston | Michael T. Monaghan | Kozo Watanabe

 

Abstract:

Gravel bars are a geographical component in rivers and known to introduce habitat heterogeneity in river ecosystems. Among the gravel bar characteristics, the hyporheic zone, the area where surface water and groundwater meets, is known to largely affect the microbial communities. Microbial communities in gravel bars are important to the biogeochemical cycle in the riverine ecosystem. In this study, we aimed to investigate the spatial distribution of microbial diversities (α and β diversity) and the biological functions in three different sampling points (downwelling, upwelling, and their intermediate point) within three gravel bars in the Tenryu River, Japan using 16S rRNA amplicon sequencing. The NMDS plots showed differences in bacterial community structures (β-diversity), with a clear separation of three points, but the α-diversity was constant. Among the microbial organisms, the Proteobacteria were found to be the most abundant taxa throughout three points. Functional Annotation of Prokaryotic Taxa (FAPROTAX) was used to identify the potential biological function. We found the chemoheterotrophy was the most abundant function throughout the three points, suggesting the importance of primary energy metabolism for the microbial community. Overall, our study highlights the changes of microbial communities’ composition among gravel bars spatial differences and future studies assessing river management.