Bacterial genus-level taxa identified by Similarity Percentage (SIMPER) analysis to explain 90% of the Bray-Curtis dissimilarities between pairs of sampled water masses. Multiple OTUs affiliated with the same taxon were combined for the analysis and visualization. For each taxon, boxplots illustrate the 25–75 percentile values (box), median (bar inside box), standard deviation (whiskers), and outliers (solid circles).