title: MICROBIAL DIVERSITY OF ARABIAN SEA (SURFACE)
design: DNA was extracted from marine water samples using DNA extraction method for bacterioplankton according to Bostrm et.al (2004) with minor modifications. The extracted DNA was quantified using NanoDrop (Thermo Scientific, USA). A region of the 16S rRNA gene covering the hyper variable V3-V4 was amplified by PCR using bacterial-specific 341F-(5' CCTACGGGAGGCAGCAG 3) and 806R-(5' GACTACHVGGGTATCTAATCC 3). The PCR products were sent to Scigenom Pvt Ltd Kerala, India. The amplicon sequencing libraries were all prepared and sequenced at Scigenom Pvt Ltd. Briefly, Amplicons of the correct size were purified using PureLink Quick Gel Extraction and PCR Purification Combo Kit (Invitrogen) following manufacturers instructions. A second PCR was performed with primers that has Illumina indexed bar code sequences. The size selection was performed with Pure link Gel extraction kit (Invitrogen). Purified products were quantified using a Qubit (Invitrogen) The library preparation was done using NEBNextUltra for DNA Library Prep Kit for Illumina. Sequencing was done in MiSeq  Illumina, 2 x 250bp cycles. Sequence data was processed using QIIME.