title: pH is the primary determinant of the bacterial community structure in agricultural soils impacted by polycyclic aromatic hydrocarbon pollution.
abstract: Acidification and pollution are two major threats to agricultural ecosystems; however, microbial community responses to co-existed soil acidification and pollution remain less explored. In this study, arable soils of broad pH (4.26-8.43) and polycyclic aromatic hydrocarbon (PAH) gradients (0.18-20.68 mg kg-1) were collected from vegetable farmlands. Bacterial community characteristics including abundance, diversity and composition were revealed by quantitative PCR and high-throughput sequencing. The bacterial 16S rRNA gene copies significantly correlated with soil carbon and nitrogen contents, suggesting the control of nutrients accessibility on bacterial abundance. The bacterial diversity was strongly related to soil pH, with higher diversity in neutral samples and lower in acidic samples. Soil pH was also identified by an ordination analysis as important factor shaping bacterial community composition. The relative abundances of some dominant phyla varied along the pH gradient, and the enrichment of a few phylotypes suggested their adaptation to low pH condition. In contrast, at the current pollution level, PAH showed marginal effects on soil bacterial community. Overall, these findings suggest pH was the primary determinant of bacterial community in these arable soils, indicative of a more substantial influence of acidification than PAH pollution on bacteria driven ecological processes.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.|Joint Open Laboratory of Soil and the Environment, Hong Kong Baptist University &Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.|Joint Open Laboratory of Soil and the Environment, Hong Kong Baptist University &Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.|Joint Open Laboratory of Soil and the Environment, Hong Kong Baptist University &Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Qinghe
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Zhenfa
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.|Joint Open Laboratory of Soil and the Environment, Hong Kong Baptist University &Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Xiangui
authors.initials: X
authors.lastname: Lin