Changes in Soil Microbial Community Structure Linked Biogeochemical Components in Subsurface Environments = Changes in Soil Microbial Community Structure Linked Biogeochemical Components in Subsurface Environments

다국어 초록 (Multilingual Abstract)

In order to elucidate the relationship among biogeochemical properties, microbial communities and the potential for affecting the fate of contaminants in subsurface environments, high-resolution site characterization (HRSC) research was performed in a test-bed site (100 m × 60 m) formerly used as a farm land for several decades. Total 72 soil samples were collected from three depths (10-40, 80-110, and 160-190 cm). The results of 16S rRNA gene sequencing showed that 68 different phylum-level lineages were present in soils. Microbial diversity in soils significantly decreased with depth. Chloroflexi and Firmicutes increased with depth, while Proteobacteria, Plantomycetes and Nitrospirae decreased with depth. The shared genera at three depths only accounted for 8% of the bacterial community suggesting that each soil layer contained distinct microbial communities. The results also well correlated with toxic metal concentrations and other physical and chemical properties in soils. Water content, As, Ni, total Cr and Pb, significantly increased with depth, but soil pH, bacterial population, total carbon, nitrate, Cd, Cu, Zn and bioavailable iron (0.5N HCl extractable iron) decreased with depth. In addition, XRF analysis indicated that the concentrations of Ca, K, S, and P were higher at the top soil layer and decreased with depth. The results suggest that the distinct micrbial communities and their associated metabolic activity in three soil layers at the site are tightly linked to the physical and geochemical variables, and subsequently influences on the distribution of metals and nitrate.