DNA-Seq of river water
The suspended bacterial community was concentrated on 142-mm diameter, 0.22-μm pore size polycarbonate filters (MilliporeSigma, Burlington, MA, USA) via vacuum filtration, DNA extraction performed using the ZymoBIOMICS-96 MagBead DNA Kit (Zymo Research, Irvine, CA, USA).Metagenomic sequencing was performed using the ZymoBIOMICS Shotgun Metagenomic Sequencing Service for Microbiome Analysis (Zymo Research, Irvine, CA, USA). Library preparation, where fragments were tagged with 8 bp internal dual-index barcode sequences with Nextera adapters (Illumina, San Diego, CA, USA), was completed by using Nextera DNA Flex Library Prep Kit (Illumina, San Diego, CA, USA) following manufacturer protocol. Library concentrations were quantified with TapeStation (Agilent Technologies, Santa Clara, CA, USA) to normalize abundances in the multiplexed pool for sequencing and quantified again using qPCR. The final library was sequenced using the NovaSeq (Illumina, San Diego, CA, USA) platform.