Fig. 2

Changes in bacterial alpha diversity, beta diversity and bacterial taxonomy along the 1.5 years of activity. A Richness and Simpson indices and B Principal Coordinates Analysis, using Bray–Curtis distance, at species level for the 210 industry samples (n = 55 for T1, n = 70 for T2, n = 85 for T3). The centroid of each ellipse represents the group mean, and the shape is defined by the covariance within each group. Adonis test values are indicated in Table S1. Distance to the centroid values were employed to evaluate the homogeneity of variances within each group. Only significant p values (p < 0.05) obtained from the Wilcoxon signed-rank test analysis are indicated. C Barplot representing the relative abundance of the 16 most relevant bacterial genera (average total abundance > 1% or at least one sample with abundance > 15%). Other bacterial genera are grouped into “Other”. A sample is represented by each bar, and samples are grouped by Surface and Time groups, indicated at the top and bottom of the plot, respectively