Microbiome structure and depth distribution in riparian sediments deposited after milldams

River fragmentations likely disrupt and reconstruct microbial community structure and distribution. In this study, we aimed to characterize detailed bacterial and fungal communities in the sediment accumulation upstream the mill dams in the NorthEast US. Amplicon high throughput sequencing was applied to decipher compositions of bacterial and fungal structures across multiple depths and milldame sites. Clear lateral and vertical spatial patterns indicate microbial assemblies are mainly driven by geographic locations and soil depths. Our results suggest that not only sediment accumulation from dams but also local concurrent conditions are important for explaining depth distribution of microbial communities and functions in fragmented rivers.