Fig. 2. Chemical and microbial characteristics of the three constructed water environments and zebrafish gut microbiota colonized at 12 dph.

a Chemical factors of water. Mean values were plotted with standard errors, and the variation among environments were tested through an ANOVA with least-significant-difference (LSD) tests. The presence of different letters denoted significant differences among environments, and the same letter indicated no significant difference. Chl-a Chlorophyll a, SOP soluble orthophosphate, TOC total organic carbon. b alpha-diversity of water and gut microbiotas. PD phylogenetic diversity. c Venn diagram of water microbiotas. The Venn diagram represent proportions of shared OTUs (operational taxonomic units) across environments over the total number of OTUs detected in all environments, but it does not provide quantitative data on the OTUs. d detrended correspondence analysis showing the dissimilarity of water and gut microbiotas at 12 dph (days post-hatching).