中文摘要：

包气带是泄漏油品进入地下水的通道,存在多种类型的微生物。研究油品泄漏场地包气带土壤中微生物丰度及群落多样性特征,可为加油站场地土壤和地下水的微生物修复提供理论依据。该研究基于土壤DNA提取,16S rDNA实时定量PCR（polymerase chain reaction）和克隆文库的构建,分析了加油站土壤中微生物丰度及群落结构特征。实时定量PCR结果表明,表层土壤微生物丰度高于深层土壤约2个数量级,未污染深层土壤中微生物丰度高于污染的深层土壤约2个数量级。RDP（ribosomal database project）分析结果表明,加油站场地表层土壤微生物种类较丰富,而深层土壤微生物组成较单一,且污染的深层土壤细菌群落多样性明显低于对照场地深层土壤。研究也发现,与汽油降解相关的微生物菌群Beta-proteobacteria是深层污染土壤的主导微生物。

英文摘要：

Migration and diffusion through the vadose zone can be an important source for groudwater contamination of hydrocarbon at gasoline spill sites. Vadose zone is rich in microbes of many types. The study on microbial abundance and community structure in vadose zone soil can provide a theoretical basis on the remediation of soil and groundwater at gas station. Based on the extraction of total soil DNA, microbial community composition and diversity at a petroleum-contaminated site near a gas station was investigated by pyrosequencing of bacterial 16 S r DNA gene fragments（polymerase chain reaction,PCR） and cloning-sequencing procedures. Real-time quantitative PCR results show that the densities of microorganisms in the topsoil are generally about two orders of magnitude higher than the deep soil;the densities of microorganisms in uncontaminated deep soil are also about two orders of magnitude higher than the contaminated deep soil.Based on the RDP（ribosomal database project） results,topsoil shows higher diversity than deep soil,uncontaminated samples show higher diversity than contaminated samples. Beta- proteobacteria is the leading microorganism in the contaminated deep soil,which plays an important role in the degradation of petroleum hydrocarbon.