16S of seawater (environmental control): 100 mg/L
Microbial communities in seawater were collected by passing 1L of seawater through 0.2 µm Sterivex filters and DNA was extracted from the filters. Extracted DNA was shipped to the Australian Centre for Ecogenomics (St. Lucia, QLD, Australia) for sequencing of the 16S rRNA gene using standard procedures. Briefly, the V4 region of the 16S rRNA gene was amplified using the primer 515f – 806r and sequenced using the HiSeq2500 platform with the V2 chemistry (2 x 250 bp) (Illumina).