On-board sequencing of the microbial community of the South Pacific Gyre

Fluorescence in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes was used to investigate the phylogenetic composition of the seven most abundant bacterial clades (determined by 16S rRNA tag sequencing) of the South Pacific Gyre (SPG). Seawater samples were collected aboard the RV Sonne SO-245 "UltraPac"cruise from Antofagasta, Chile (17.12.2015) to Wellington, New Zealand (28.01.2016). A total of 15 stations were sampled at multiple depths from surface (20 m) to ~5000 m. Total cell counts (TCC, by DAPI staining) and FISH were carried out as described in Bennke et al. (2016). DAPI and FISH stained cells were visualised and counted automatically using a fully automated image acquisition and cell enumeration system (Bennke et al., 2016).