Biodiversity Research On Acidophilic Microorganisms In An Acid Mine Drainage Aera

In thegeneration of acid mine drainage (AMD), acidophilic iron-andsulfur-oxidizing microorganisms have a pivotal role. AMD with low pH (below3)contains high concentrations of Fe, Al, Cu and SO42-, which could not be directlyrecycled, and cause a serious threat to water，farmland etc.In order to understand thecharacteristics ofacidophilic community structure, we collected samples from an acidmine drainage area in Anhui province, China,in October2010and September2012,respectively. In this research, we used molecular technique to study and discuss thediversity of microorganisms, then analyzed the relationship between the communitystructure and environmental factors in acidic mine drainage. The main results were asfollows:The pH of acid mine drainage and solid samples were below3.0, and containedhigh concentrations of Fe, Al, Zn, Mn, Cu. The main form of Fe was Fe3+.The biodiversity of bacteria and fungus in the soil samples was more than theacid mine drainage samles.Besides, many sequences in libraries were closely relatedto many isolated strains, which were tolerant to low pH and heavy metals.In thebacterial clone librariesof soil samples,the bare abandoned rock samples (PD and1M)contained more autotrophic acidophilic microorganisms. The main reason might bethat the environment of PD and1M was worse, which was not suitable forheterotrophic microorganism. In the eukaryotic clone libraries,the biodiversity of thevegetation covered samples LW and XC was much more than the bare abandonedrock samples PD and1M.In the bacterial clone librariesof the water samples, theabundance of heterotrophic microorganism and photosynthetic algae was higher in, asa result of the low concentration of Fe2+.In the eukaryotic clone libraries, onlycontained Ochromonas sp. and Chlorella protothecoides var.acidicola, which were ina balance between predator and prey.Moreover, we got some new findingsin the study. Many sequences in librarieswere closely related to some isolated strains, which were not tolerant to low pH andheavy metals,but had a high abundance, such as Scytinostroma sp., Loramycesmacrospores,Acidisphaera sp..These microorganisms might formsymbioticrelationship with other microorganisms, which were tolerant to low pH and heavymetals, in this way, reducing the toxicity of environment. However, the real survivalmechanism need further study.Another one was that ammonia-oxidizing archaea haddistant relative with studied AOA. It could be speculated thatnew ammonia oxidizingarchaea existed in this environment.Principal component analysis and detrended correspondence analysis suggestedthat the similar geochemical conditionsin same batch samples generated the similarmicrobial community structure. The environmental factor had effect on thecommunity composition.