Fig. 2

Community distribution and alpha diversity. a Bar plots indicate relative abundances of EMIRGE-reconstructed 16S and 18S rRNA gene sequences. Site salinities are shown in the upper left plots, and transect distances are given in the lower plots. Taxa are coloured at the order level. For each plot, samples from the water column (left) and sediment (right) are further categorised into freshwater, brackish or marine, as indicated in the top left plot. b Boxplots illustrate Shannon indices and relative OTU richness in both sediment and water column environments across the salinity gradient for archaeal, bacterial and microeukaryal communities (n = 36). Colours indicate environment type (freshwater, brackish and marine) based on the salinity gradient. Boxes represent the interquartile range (IQR) between the first and third quartiles and the horizontal line inside the box represents the median. Whiskers represent the lowest and highest values within 1.5 times the IQR from the first and third quartiles, respectively. Individual sample values are shown as dots. Asterisks (^∗) indicate a significant difference between all water column and sediment samples (Wilcoxon p < 0.05)