Fig. 1: Overall microbiome compositional structure of B. europaea and the surrounding environment.

Principal Coordinate Analyses (PCoAs) of the Bray-Curtis distances calculated on microbiome profiles at genus taxonomic level, obtained from 16S rRNA gene sequencing (A and B) and phylogenetic assignation of metagenomic reads (C–F), describing different features of the available coral and environmental samples. The first and second principal components (PCo1 and PCo2) are plotted in all graphs and the percentage of variance in the dataset explained by each axis is reported. A PCoA based on 16S rRNA gene data showing the structure of B. europaea associated microbiomes compared to the surrounding environment (permutation test with pseudo-F ratio, p value = 0.001). B PCoA based on 16S rRNA gene data showing B. europaea microbiomes associated to the 3 different coral compartments (permutation test with pseudo-F ratio, p value = 0.001). C PCoA based on metagenomics data showing B. europaea microbiomes associated to the 3 different coral compartments (permutation test with pseudo-F ratio, p value = 0.001). D–F PCoAs based on metagenomics data comparing B. europaea microbiome in different anatomic compartments in samples collected at different acidified conditions. A–C legend: mucus samples, yellow squares; soft tissue samples, green circles; skeleton samples, gray triangles; water samples, light blue diamonds; sediment samples, black reversed triangles. PCoA based on metagenomics data comparing B. europaea mucus (D), soft tissue (E) and skeleton (F) microbiomes in corals collected at different acidified conditions. Samples are depicted as symbols (same as in panels A–C) filled in shades of color from lighter color (Site 1, control site, non-acidified) to darker colors (Site 2, moderate acidification, and Site 3, strong acidification).