title: Responses of soil microbial activity to cadmium pollution and elevated CO2.
abstract: To address the combined effects of cadmium (Cd) and elevated CO2 on soil microbial communities, DGGE (denaturing gradient gel electrophoresis) profiles, respiration, carbon (C) and nitrogen (N) concentrations, loessial soils were exposed to four levels of Cd, i.e., 0 (Cd0), 1.5 (Cd1.5), 3.0 (Cd3.0) and 6.0 (Cd6.0) mg Cd kg(-1) soil, and two levels of CO2, i.e., 360 (aCO2) and 480 (eCO2) ppm. Compared to Cd0, Cd1.5 increased fungal abundance but decreased bacterial abundance under both CO2 levels, whilst Cd3.0 and Cd6.0 decreased both fungal and bacterial abundance. Profiles of DGGE revealed alteration of soil microbial communities under eCO2. Soil respiration decreased with Cd concentrations and was greater under eCO2 than under aCO2. Soil total C and N were greater under higher Cd. These results suggest eCO2 could stimulate, while Cd pollution could restrain microbial reproduction and C decomposition with the restraint effect alleviated by eCO2.
authors.affiliation: SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China.
authors.forename: Yi Ping
authors.initials: YP
authors.lastname: Chen
authors.affiliation: 1] SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China [2] University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Environmental Science, Xi'an University of Architecture and Technology, Xi'an 710062, China.
authors.forename: Yong Jun
authors.initials: YJ
authors.lastname: Liu
authors.affiliation: SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China.
authors.forename: Feng An
authors.initials: FA
authors.lastname: Jia
authors.affiliation: Elizabeth Macarthur Agricultural Institute, Department of Primary Industries, Menangle, NSW 2568, Australia.
authors.forename: Xin Hua
authors.initials: XH
authors.lastname: He
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry*; D004787:Environmental Pollution; D064307:Microbiota; D009584:Nitrogen / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D012987:Soil; D002104:Cadmium; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen