不同空间位点沉积物理化性质与微生物多样性垂向分布规律

Vertical Distribution of Physicochemical Characteristics and the Microbial Diversity in Different Spatial Sediments Samples in Lake Taihu

运用化学分析方法和PCR-DGGE技术从沉积物化学及基因角度对太湖不同空间位点沉积柱理化性质（pH、Eh）、营养盐（TN、TP、OM）及微生物多样性的垂向分布及相关性进行研究.结果表明,沉积物Eh在水-土界面处于轻度还原状态,表层下,随沉积深度的增加迅速下降,还原性逐渐增强.沉积物pH在整个剖面上变化幅度不大,在7.2--7.8变动.沉积物中含有丰富的营养盐,总氮和总磷最高含量分别为2.436 mg/g和0.731 mg/g,其剖面分布特征表明,沉积物表层总氮和总磷含量远高于底层,其含量随深度增加而降低.沉积物有机质含量在15 cm以上变化幅度较大,随着沉积深度的增加,有机质含量明显减少.沉积物中微生物群落结构显示了明显的空间分布多样性差异.三位点TN与OM之间均存在显著的相关性,但理化指标与营养盐以及微生物群落多样性指标之间不存在显著的相关性.

The physicochemical characteristics, nutritions and the microbial community diversity of sediment core samples of three different space locations in the Lake Taihu were studied by fumigation-digestion and PCR-DGGE analysis respectively. The results indicated that below the surface of sediments Eh declined rapidly with increase of sediment depth and it was under anaerobic condition except the top layer of sediment. pH value changed silightly in the profile of sediments, which ranged from 7.2 to 7.8. TN and TP concentrations in sediments of Lake Taihu were high,and the maximum concentrations reached 2.436 mg/g and 0.731 mg/g, respectively. Their vertical profiles showed that TN and TP concentrations in surface sediments were much higher than in deeper layers and decreased with the increase of the depth of sediment layers. OM concentrations declined rapidly at the top 15 cm of sediment layers. There were prominent difference spatially in microbial diversity and the comparability and dynamics of community structure between different sediment samples of different space locations and different depth. The little significant correlation at α≤ 0.05 level was observed between the Eh, pH, percentage organic matter, TN concentration and TP concentration and microbial community structure diversity index except of TN concentration and percentage organic matter.