Relationships between Microbial Compositions and Hydrochemical Factors in Nitrate Contaminated Groun dwater of Hun River Alluvial Proluvial Fan, China

Abstract

The objective of this study was to explore the mic robial community diversities and the relationships between microbial community compositi ons and hydrochemical factors in nitrate contaminated groundwater of Hun River alluv ial plain. The method of polymerase chain reaction (PCR)-denaturing, gradient gel elect rophoresis (DGGE) gene fingerprints combined with canonical correspondence analysis （ （（ （ CCA ） ）） ） were applied. The Operational Taxonomic Units (OTUs) of all the sampl ing sites had a certain degree of heteroplasmy and 75% OTUs presented in less than ha lf of the sampling sites. The un- weighted pair group mean average (UPGMA) cluster an alysis showed that the microbial community similarity of all the sampling sites were not relatively high (0.6-0.8). The distribution of microbial community positively corr elated with nitrate. The dominant bacteria of the nitrate contaminated groundwater ma inly included Hyphomicrobium denitrifican sp. , Halanaerobium praevalens sp. , Desulfotomaculum reducens sp. , Nitrosospira multiformis sp., among which the Nitrosospira multiformis sp. and Sulfurovum sp. existed in all the sampling sites. CCA results indicated that Mn 2+ and NO 3 - were the most relevant hydrochemical factors to regulate the microbial composition in nitrate contaminated groundwater of this area, and next wer e Fe 2+ and SO 4 2- . The results could provide references for the bioremediation of the ni trate contaminated groundwater of Hun River alluvial plain Keywords: Bacteria, Bioremediation, PCR-denaturing.