Fig. 6
The alpha diversity of the bacterial and fungi in the SRS and ORR Hg contaminated sites based on the shotgun sequencing grouped by the level of contamination and the sampling season. For bacteria at the phylum level (a), the order of diversity with respect to the level of contamination was R > M > L > H. These abbreviations pertain to levels of mercury contamination- R (Ref), M (middle), L (low) and H (high), respectively. The highly contaminated sites were less diverse due to Hg toxicity. For the seasonal consideration, the average median diversity index of the S samples was higher than that of the W samples. However, the average maximum diversity indices of the two groups were not significantly different. At the genus level (b), the “low” mercury contaminated samples had the highest bacterial diversity index, but the average maximum diversity indices of the samples were not substantially different from each other. For the fungi at phylum level (c), the average median diversity indices of the samples based on the contamination levels were almost the same except the “high” sample which was substantially lower. The average maximum diversity indices based on the sampling season indicates that the W samples were more diverse than the S samples. At the genus level (d), the average median diversity indices based on the level of contamination were almost equal, but the average maximum diversity of the “low” sample was higher than the rest. Based on the sampling season, the W samples were more diverse than the S samples.
