重金属复合污染下土壤微生物群落功能多样性动力学特征

KINETICAL CHARACTERISTICS FOR FUNCTIONAL DIVERSITY OF MICROBIAL COMMUNITIES IN SOILS POLLUTED WITH MIXED HEAVY METALS

用碳素利用法对浙江省天台铅锌银尾矿区重金属复合污染土壤微生物群落功能多样性动力学特征进行了初步探讨。研究结果表明 ,矿区重金属复合污染降低了供试土壤的微生物群落代谢剖面 ,且群落代谢剖面值与培养时间之间呈非线性关系 ,其变化过程符合微生物种群生长动态模型 (S形 )。随着重金属复合污染程度的加剧 ,土壤微生物群落功能多样性动力学参数K和r值越低 ,参数s值所需的时间则越长。上述动力学参数与群落代谢剖面各自的主成分分析结果显示 ,微生物群落功能多样性的动力学参数K值和s值能够很好地区分矿区土壤重金属污染程度 ,并且其区分效果比微生物群落代谢剖面值好。土壤微生物群落功能多样性动力学特征的变化可以较好地显示矿区重金属复合污染土壤微生物群落对碳源利用模式的差异 ,反映矿区特定生境土壤微生物群落功能多样性的变化 ,在一定程度上揭示重金属胁迫下环境微生物种群作用机理。

A kinetic method is presented for characterizing the physiological state of microorganisms capable of carrying out specific metabolic function in red soils taken from a lead-zinc mining area. The results showed that soil microbial community metabolic profiles were inhibited by mixed heavy metals pollution, exhibiting non-linear correlation with the incubation time, and the shape of the color development curve was generally sigmoidal. Test well OD values over time suggested a kinetic model based on the density-dependent logistic growth equation. The kinetic parameters generated by the model can be used as surrogates for single-time-point data in constructing carbon source utilization patterns. The kinetic parameter K and r values decreased significantly with level of mixed heavy metals pollution. The higher pollution degree, the lower microbial community profiles, the lower microbial metabolic processes and the microbial growth rate. Principal component analysis (PCA) single-time-point microplate data and parameters of the kinetic model showed that parameters K and s could be effectively used to differentiate degrees of heavy metal pollution in the mining zone with efficiency higher than AWCD. Change in dynamic characteristics of the microbial community functional diversity well reflects differences in model of microbial communities utilizing C sources in the soils polluted with mixed heavy metals, and change in soil microbial community functional diversity in particular eco-environment like mining zones, thus revealing to some extent functional mechanism of microbial communities in environment under heavy metal stress.