垃圾填埋场细菌种群空间分布及组成多样性研究

Spatial composition and diversity of bacterial community in a municipal solid waste landfill via denaturing gradient gel electro- phoresis (DGGE)

采用PCR -DGGE技术对垃圾填埋场细菌种群垂直分布及组成多样性进行了研究.结果表明:垃圾填埋场细菌种群组成波动较大,某些种群对环境因子的变化十分敏感.在填埋年龄已达3a的取样点,细菌种群的多样性随着垃圾填埋深度的增加而呈现“多—少—多”的变化趋势,各种群间相对密度也呈现由不均一到均一的变化规律,部分层次优势种和非优势种发生较大变化.填埋深度4 0m至6. 2 5m左右的区域是填埋场微生物区系组成发生变化的过渡区,该区域细菌种群的多样性较小,亲缘关系相差比较大的种交叉在一起,具有明显的过渡特征.从时间因素来看,填埋场同层次微生物群落组成随时间延长,种群构成趋于稳定.表层垃圾1～2a内,细菌种群处于交替更叠的阶段,日趋发育成熟8 .2 5m以下层次的细菌种群主要受填埋深度影响。

Microbes are assumed to possess strong decomposing advantages in waste composting process, but little is known about the effect of such practice on bacterial diversity in Municipal Solid Waste Landfill (MSWL), where a specific biota transiting aerobic state to anaerobic one vertically. To understand more details about microbial ecology in MSWL, the composition and diversity of bacterial communities in three sample sites of various landfill age (1～3 year) was analyzed by PCR-DGGE technique. Significant fluctuations of bacterial communities with different landfill time and layers were revealed, and for some species, the population was observed to be influenced by physic-chemical characters of habitat as the corresponding the band intensity in DGGE gel changed. In a three-year old landfill site, the diversity of bacterial species showed a shift tendency of higher-lower-higher level as depth increased vertically. Also, the comparative intensity and heterogeneity of each species demonstrated a variability of symmetry-asymmetry-symmetry process. Some dominant and non-dominant species changed significantly in some layers. The layers between 4.0?m and 6.25?m were the transitional section in which the composition and diversity of bacterial communities changed sensitively. These layers had lower bacterial diversity yet the closest relative species, revealing an apparent transition characteristic. Species composition at the same layers gradually showed higher similarity with time going. As regard to the temporal factor, the bacteria communities in surface layer of one or two years were undergoing the drastic change and gradually became mature. Investigations also indicated that bacterial species in layers under 8.25?m were influenced more by landfill depth than by time.