Shotogun metagenome of the eastern Indian Ocean
The seawater for metagenomic analysis (6-7 L, 10 m layer) was sequentially filtered through a 3.0-m-pore-size Nuclepore filter (47-mm-diameter, Whatman, Clifton, NJ,USA) and a 0.22-m-pore-size Sterivex filter unit (Millipore, Bedford, MA, USA). The filters were subsequently stored at -80 C until further processing in the lab. Samples of the Sterivex cartridge filters were used for the analysis of this study. DNA extraction was carried out with the use of MagAttract PowerWater DNA/RNA Kit (QIAGEN) according to the manufacturers instructions. Extracted DNA was fragmented (400bp) using the Covaris ME220 (Covaris LLC., MA, USA), and the MGIEasy Universal DNA Library Prep Set was used to prepare sequencing libraries. Shotgun sequencing of metagenome samples was performed using the DNBSEQ-G400 platform (2200bp) (MGI Tech Co., Ltd., Shenzhen, China).