Characterization of bacterioplankton communities in the Galapagos Archipelago under contrasting environmental conditions by 16S rRNA amplicon sequencing

We investigated three contrasting oceanographic settings in the Galapagos Archipelago regarding their suitability to represent future ocean conditions in research on organic carbon pools and bacterioplankton communities. Compared to a reference site representative of ambient pH and temperature, we studied a submarine CO2 vent at Roca Redonda (RoR), and an upwelling site at Bolivar Channel (BoC) subjected to a weak El-Nino event at the time of sampling in October 2014. We recorded physico-chemical parameters, and quantified particulate and dissolved organic carbon, transparent exopolymeric particles, and the potential of the water to form larger marine aggregates. Free-living (filtered on 0.2µm) and particle-attached (filtered on 3µm) bacterial communities were assessed via 16S rRNA gene sequencing on Illumina MiSeq (V3V4 hypervariable region).