Thirtythree diffuse fluid and water column samples and 23 samples from surfaces of chimneys, rocks and fauna were subjected to a combined analyses of 16S rRNA gene sequences, metagenomes and real-time in situ measured geochemical parameters to study distribution and niche-partitioning of sulfur-oxidizing bacteria (SOB) in deep-sea hydrothermal environments of the Manus Basin, a back-arc fast-spreading center located between New Britain and New Ireland in the Bismarck Sea. High throughput 16S rRNA gene amplicon sequences obtained by Illumina paired-end sequencing using the primer combination Bakt_341F and Bakt_805R for all samples were analyzed as well as full-length 16S rRNA genes using a Pacific Biosciences RSII sequencer. Additionally, 5 metagenomes were sequenced (Illumina HiSeq 2500, paired-end shotgun), assembled, binned, and re-binned, resulting in 11 Sulfurovum-related, 5 Sulfurimonas-related and 12 SUP05-clade bins. These bins were analyzed with respect to genomic variability among hydrothermal vent SOB and especially with respect to the differentiation of their sulfur oxidation genes.Correlating distribution patterns to real-time geochemical data, tentative niches could be assigned to key hydrothermal SOB clades: Sulfurovum Epsilonproteobacteria were mainly found attached to surfaces exposed to diffuse venting, while the SUP05-clade dominated the bacterioplankton in highly diluted mixtures of vent fluids and seawater. The high diversity within Sulfurimonas- and Sulfurovum-related Epsilonproteobacteria observed in this study was proposed to be derived from the high variation of environmental parameters such as oxygen and sulfide concentrations across small spatial and temporal scales.

1 Sample names reflect i) collection sites: CTD - CTD overlaying water column samples; SuSU Knolls field: NSu - North Su; PACMANUS field: Fw - Fenway (PACMANUS), RR - Roman Ruins, SnC - Snowcap, Sol8 - Solwara 8, StM - Satanic Mills and ii) sample type and number: A - fauna surfaces, F - fluids/water, R - rock/chimney; iii) a and b indicate different samples of the same fluid/rock. ND - 'not determined'. 0 - below detection limit.2 Temperature and pH were determined by in-line probes attached to the KIPS-nozzle3 Gas concentrations were measured by in situ mass spectrometry parallel to the filtering of fluids.4 Gibb's free energy calculations available from sulfide oxidation were done with a conservative sulfate concentration estimate of 28 mM (background sea water value).

Supplement to: Meier, Dimitri V; Pjevac, Petra; Bach, Wolfgang; Hourdez, Stéphane; Girguis, Peter R; Vidoudez, Charles; Amann, Rudolf; Meyerdierks, Anke (2017): Niche partitioning of diverse sulfur-oxidizing bacteria at hydrothermal vents. The ISME Journal, 11(7), 1545-1558