title: Assessing the microbial community and functional genes in a vertical soil profile with long-term arsenic contamination.
abstract: Arsenic (As) contamination in soil and groundwater has become a serious problem to public health. To examine how microbial communities and functional genes respond to long-term arsenic contamination in vertical soil profile, soil samples were collected from the surface to the depth of 4 m (with an interval of 1 m) after 16-year arsenic downward infiltration. Integrating BioLog and functional gene microarray (GeoChip 3.0) technologies, we showed that microbial metabolic potential and diversity substantially decreased, and community structure was markedly distinct along the depth. Variations in microbial community functional genes, including genes responsible for As resistance, carbon and nitrogen cycling, phosphorus utilization and cytochrome c oxidases were detected. In particular, changes in community structures and activities were correlated with the biogeochemical features along the vertical soil profile when using the rbcL and nifH genes as biomarkers, evident for a gradual transition from aerobic to anaerobic lifestyles. The C/N showed marginally significant correlations with arsenic resistance (p = 0.069) and carbon cycling genes (p = 0.073), and significant correlation with nitrogen fixation genes (p = 0.024). The combination of C/N, NO(3) (-) and P showed the highest correlation (r = 0.779, p = 0.062) with the microbial community structure. Contradict to our hypotheses, a long-term arsenic downward infiltration was not the primary factor, while the spatial isolation and nutrient availability were the key forces in shaping the community structure. This study provides new insights about the heterogeneity of microbial community metabolic potential and future biodiversity preservation for arsenic bioremediation management.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Xiong
authors.forename: Zhili
authors.initials: Z
authors.lastname: He
authors.forename: Joy D
authors.initials: JD
authors.lastname: Van Nostrand
authors.forename: Guosheng
authors.initials: G
authors.lastname: Luo
authors.forename: Shuxin
authors.initials: S
authors.lastname: Tu
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
authors.forename: Gejiao
authors.initials: G
authors.lastname: Wang
mesh_terms: D001151:Arsenic / Q000633:toxicity*; D001419:Bacteria / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D057486:Carbon Cycle / Q000187:drug effects / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics; D004734:Energy Metabolism / Q000187:drug effects / Q000235:genetics; D004777:Environment; D005658:Fungi / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics*; D014644:Genetic Variation; D058458:Nitrogen Cycle / Q000187:drug effects / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010758:Phosphorus / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*; D013997:Time Factors
chemical_list: D012989:Soil Pollutants; D010758:Phosphorus; D002244:Carbon; D001151:Arsenic