Fig. 4

Beta diversity across the study area. Principal coordinates analysis (PCoA) of a swab bacterial communities and b corrected skin bacterial communities. The first and second PCoA axes correspond to the y and x axes of each plot, respectively. The percent variance explained by each axis is denoted as the axis label. The four most important ASVs and their effect sizes are indicated by biplot arrows. Subplots c to j demonstrate the correlation of the first (c, f) and second (g, j) PCoA axis values with the temperature (c, g), conductivity (d, h), pH (e, i) and dissolved oxygen (f, j). Circle and square markers denote the northern and southern basins respectively. Blue, grey and orange markers denote water, swab and corrected skin communities, respectively