Effect of Changing Conditions on the Composition of the Bacterial Community of Mine Waters

The leaching of hydrometallurgical metals from the ores of sulfide deposits is associated with the formation of acid mine drainage (AMD), which, in turn, provokes the acidification of mining areas. Mine drainage (MD) is a special ecological niche with natural selection formed by the low pH of the environment and the toxicity of the leached metals. Microbial communities of the MD are a good model for changes in bacterial composition under changing conditions. We have investigated the changes in the microbiota composition of MD samples taken from the Shanuch sulfide copper-nickel deposit (Kamchatka, Russia). Changes in the bacterial composition of the community are artificially provoked by transferring the initial microbiota (inoculum) to six media of different chemical compositions. The selected media provide various scenarios for possible changes in the microbiota under simulated changes in the chemical composition. Molecular analysis shows that the original MD community includes representatives of 13 genera in which strict acidophilic bacteria represent <20% of the clones. Organic additives in media provoke the dominance of heterotrophic bacteria only in one case. In general, model experiments reveal significant changes in the composition of autotrophic bacteria leaching metal, both at the species level and at the level of strains: the diversity of bacteria decreases and the analysis reveals fewer strains.

Automated summary

The study investigated changes in the microbial community composition of mine drainage samples from the Shanuch sulfide copper-nickel deposit, with changes in bacterial composition artificially induced by altering chemical compositions. The experiments revealed significant changes in autotrophic bacteria leaching metal at both the species level and strain level under simulated changes in chemical composition.