Molecular Ecology Research Of Acidophilic Microorganisms In An Acid Mine Drainage Aera

Acid mine drainage(AMD)is generated when waste sulfide ores come into contact with oxygenated water,and the oxidation process can be greatly enhanced by microbial activity because many acidophilic microorganisms can accelerate dissolution of sulfide minerals through oxidation of ferrous iron and/or reduced forms of sulfur.To control generation of AMD as well as bioremediate the contamination,the structure and evolution of acidophile community related to generation of AMD should be comprehended,and the function of important acidophiles in the geochemical cycle of Fe and S should also be clarified.Samples were collected from an AMD lake and surrounding area at Xiang Mountain,Anhui Province.The structure and succession of acidophile community,as well as the role which important acidophiles play in the acid ecosystem were studied using the combination of clone library and high-throughput sequencing technology.The main results are as follows:1.The AMD lake was very acidic,pH of which was always below 3.2,and contained high concentrations of metals,SO42-and nutrients such as N,P.Sample AMD-12-5 was newly generated and pH was 2.5,concentrations of Fe and SO42-of which were as high as 2 and 10 times of those in the AMD lake.2.The results of clone library showed Proteobacteria was the major phylum in the acidophile community in summer and Ferrovum myxofaciens was the main Fe-oxidized bacteria in the ecosystem.Eukaryotic community consists of Chlorella protothecoides var.acidicola and Oxytricha spp.The flourish of algae brought the ecosystem primary productivity.3.The abandoned ore samples were collected in waste dump around the AMD lake were strongly acidic and pH of every sample was below 3.0.Acidobacteria accounted for high percentages in all four samples and they play a great role in the matter cycle and energy flow in the waste ore ecosystem.The organic matter content as well as pH had positive correlation to the biodiversity.On the contrary,relationship between sulfate as well as P and biodiversity was negative.4.The results of high-throughput sequencing showed that the Shannon index of acidophlies of AMD lake in autumn was higher than that in winter while biodiversity of the more acidic sample AMD-12-5 was lower than that of AMD lake.Similar to summer,Proteobacteria was still the most abundant phylum in autumn and winter community.On the contrary,Bacteroidetes was the major phylum in the sample AMD-12-5?5.In autumn and winter,Ferrovum myxofaciens was also the main Fe-oxidizer in the AMD lake.Chitinophaga spp.was the most abundant bacteria in the AMD-12-5.To our knowledge,this is the first occasion the bacteria of the genus were found the dominant components in an acidic habitat.6.Chlorella protothecoides var.acidicola and Ochromonas spp.were main eukaryotic microbes in AMD lake in antumn while Oxytricha spp.and Chlamydomonas acidophila were dominant in winter.7.The typical acidophliles community that generated AMD in waste ores in the area consists of Sulfobacillus spp.,Leptospirillum ferriphilum,Ferroplasma acidiphilum and Acidiferrobacter thiooxydans.8.The ammonia oxidation in the area was probably driven by ammonia-oxidizing archaea,and new genus of ammonia-oxidizing archaea existed in the waste ore samples.