Cates61
16S rRNA genes of extracted DNA were amplified using polymerase chain reaction (PCR) to yield three replicate reactions per sample. Variable region V4 of the 16S rRNA gene was targeted using forward primer 515F and reverse primer 806R with modification by Walters et al. (2016), which increased degeneracy of bases that have caused detection bias among some bacterial clades. Primers also had barcodes and Illumina sequencing adapters added, following Kozich et al. (2013).