16S rRNA  of soil microbes from beneath managed aquifer recharge tests
Briefly, soil DNA was extracted  with a PowerSoil DNA Isolation Kit (QIAGEN). The Qubit 4 Fluorometer  (Invitrogen) was used to quantify DNA extracts. PCT amplicons (~550 bp) were  generated from PCRs with soil DNA and 16S rRNA gene primers targeting the V4  and V5 variable regions. The PCR amplicon sequencing pipeline used in this  study was adapted from Illumina MiSeq platform protocol for 16S metagenomic  libraries21. The  overall pipeline included steps for the primary PCR using 16S rRNA primers23, PCR clean-up, library  preparation (adding unique sequencing indices [barcodes] to each PCR  amplicon), normalizing DNA concentrations of each library, and library  pooling. The pooled library was sequenced on the Illumina MiSeq (600 cycles  v3 PE300 flow cell kit) at the University of California, Davis Genome Center