Fig 5. Main environmental factors driving variation in community structure for the bacterial and archaeal communities analyzed.

Canonical Correspondence Analysis (CCA) depicting relationships between operational taxonomic units (OTUs) and environmental explanatory variables (habitat of origin, site location and depth) for the bacterial and archaeal communities. OTU identification not available for Archaea. Bacterial OTUs shown were discriminated by SIMPER analysis as each of them explains more than 2% of the community similarity within each sampling grouping. Note that reference level of each explanatory variable (i.e., Seawater, Buoy One and 5m depth) is represented by the intersection point of the two axes. Percentages represent amount of whole variation accounted for by each axis.