arge accumulation of heavy metals in organic layers of forest soils may adversely affect the structure and diversity of microbial communities.

实验内容：

The objective of this study was to assess the influence of different soil chemical properties on structure and diversity of microbial communities in soils polluted with different levels of heavy metals. The soil samples were taken at ten sites located in the vicinity of the cities of Legnica and Olkusz, differently polluted with Cu, Zn and Pb.

The samples were measured for pH and the contents of organic C (Corg), total N (Nt), total S (St) and total Zn, Cu and Pb. The measured gross microbial properties included microbial biomass (Cmic) and soil respiration (RESP).

The structure of soil microbial communities was assessed using phospholipid fatty acid (PLFA) analysis and the structure of soil bacterial communities using pyrosequencing of 16S rRNA genes.

To assess diversity of the bacterial communities the Chao1 index was calculated based on the pyrosequencing data.

结论：

For Cmic and RESP the most important factors were Nt and Corg, respectively. The structure and diversity of soil microbial communities revealed by PLFA profiles and pyrosequencing depended mainly on soil pH. The effect of high heavy metal contents on soil microbial properties was weaker compared with other soil properties.

High

concentrations of heavy metals negatively affected RESP and the Chao1 diversity index. The heavy metal

pollution altered the structure of microbial communities measured with PLFA analysis, but the effect of

heavy metal pollution was not observed for the structure of soil bacteria measured by pyrosequencing. （PLFA比16S更敏感地反映环境对微生物群落结构的影响）

最终结果：

The obtained results indicate that the use of soil microbial properties to study heavy metal effects may be difficult due to confounding influences of other environmental factors.