Effects of Cadmium and Mercury alone and in Combination on the Soil Microbial Community Structural Diversity

摘要

To assess effects of cadmium (Cd) and mercury (Hg) alone and in combination on soil microbial community structural diversity, an incubation experiment was conducted, employing two soils, namely, the marine sediment silty loam soil and the yellowish red soil, in which five levels of Cd, Hg or Cd and Hg in combination were added. After incubated 56 days, phospholipid fatty acids (PLFAs) were tested. The results showed that the composition of the microbial communities changed significantly after different levels of metals application. The principal component analysis (PCA) of PLFAs indicated the structure of the microbial community was also significantly influenced by the pollution of metals, with the increases in PLFAs biomarkers for fungi and actinomycetes, and the increases in the ratio of Gram-positive to Gram-negative bacteria. By comparing the effects of Cd, Hg alone and in combination, the results revealed that the combined pollution of Cd and Hg had higher toxicity to soil microbial community structural diversity than that of Cd or Hg applied alone.