Effects of Freshwater Acidification on the Gut Microbial Community of .

Freshwater acidification (FA) has become a global environmental problem, posing a potential threat to freshwater ecosystems. The gut microbiota plays a crucial role in the host's response and adaptation to new environments. In this study, we investigated the changes in microbial communities in Red-eared slider () under acidic conditions to reveal the ecological impacts of acidification on freshwater turtles. The results showed that there were significant differences in β-diversity ( = 0.03), while there were no significant differences in the α-diversity of gut microbiota in between the different levels of acidification (pH of 5.5, 6.5, 7.5). Both the Gut Microbiome Health Index (GMHI) and the Microbial Dysbiosis Index (MDI) exhibited significant differences when comparing environments with a pH of 5.5 to those with a pH of 6.5 ( < 0.01). A comparative analysis between pH levels of 5.5 and 6.5 also revealed substantial differences ( < 0.01). Likewise, a comparative analysis between pH levels of 6.5 and 7.5 also revealed substantial differences ( < 0.01). At the phylum level, Firmicutes, Fusobacteria, and Bacteroidota formed a major part of the gut microbial community, Fusobacteria showed significant differences in different acidity environments ( = 0.03). At the genus level, , , unclassified Eubacteriaceae, and __group showed significant differences in different acidity environments. The pH reduced interactivity in the gut microbiota of . In addition, LEfSe analysis and functional prediction revealed that the potentially_pathogenic and stress_tolerant functional characteristics also showed significant differences in different acidity environments. The findings underscore the pivotal role of the gut microbiota in in response to freshwater acidification and provide a foundation for further exploration into the impacts of acidification on freshwater ecosystems.