16S rRNA sequencing of estuary biofilm
DNA extraction was performed using the DNeasy PowerSoil Pro Kit. Swab tips were added to individual PowerBead tubes with flame-sterilized forceps. Bacterial community composition in isolated DNA samples was characterized by amplification of the V4 variable region of the 16S rRNA gene by polymerase chain reaction using the forward primer 515 and reverse primer 806 from the Earth Microbiome Project protocol. PCR was performed using Phusion Plus PCR Master Mix (Thermo Scientific F631L). PCR products were purified with AMPure XP Beads (Beckman Coulter A63881), and concentrations were assessed using a Qubit dsDNA HS assay kit (ThermoFisher, Q32854) and a Promega GloMax plate reader. Equimolar 16S rRNA PCR products from all samples were pooled prior to sequencing.