Figure 4

Taxonomic analysis of the microbiomes in the hemp retting (‘HR’) vs no hemp retting (‘nHR’) groups. (a) Taxonomical classification of the bacterial communities from Lake Slone. Relative abundances are presented at the phylum level. Samples from the periods of hemp retting (‘HR’) are coded in green, samples from the no hemp retting (‘nHR’) group are in purple. (b) Principal Component Analysis plot of the taxonomical structures of all samples in two groups—‘HR’ (green) vs ‘nHR’ (purple); (c) Hierarchical clustering (unweighted pair group method with arithmetic mean, UPGMA) based on taxonomy Bray–Curtis dissimilarity matrix (MEGAN). Samples from the two groups are colour coded—the ‘HR’ group in green and ‘nHR’ in purple. Heat map of the normalised values of the selected environmental factors showing the highest correlation to the taxonomic composition of the microbial communities, calculated by Mantel test (bioenv and mantel functions in vegan package), values of r-statistic indicated on the right, p < 0.01; (d) Extended error bar plot showing significant differences (p < 0.05) in the taxa abundances at the phylum level for ‘HR’ (green) vs ‘nHR’ (purple) groups, calculated with two-sided Welch’s t test (STAMP).