Reconstruction of microbial community structures as evidences for soil redox coupled reductive dechlorination of PCP in a mangrove soil·^

摘要

The aim was to investigate the influence of pentachlorophenol (PCP) on the soil microbial communities and the coupled mechanism between PCP reductive dechlorination and soil redox under anaerobic condition. Accordingly, a siurry incubation experiment was carried out in which bacterial and archaeal communities were detected by MiSeq amplicon sequencing. The original microbial community balance was gradually disrupted and new miao-bial structure was reconstructed subsequently through self-regulation and acclimation during PCP transformation, coupling with the changes of soil biogeochemical redox dynamics. The phylum Bacteroidetes predominated during the earlier PCP dechlorination period and then was progressively replaced by Proteobactería and Firmicutes groups when PCP was mostly transformed into 2,3,4,5-TeCP and 3,4,5-TCP. Heatmap and hierarchical cluster analysis revealed the ClostridiumAike, Ceobacter-ike and Deha/ococcoides-like organisms enriched concurrently during PCP reductive dechlorination processesThe relative abundance changes of the redox-active microorganisms, together with their relevance to the corresponding biogeochemical redox processes, showed that PCP dechlorination, Fe(III) and SO~2_4- reduction, as well as methanogenesis were coupled terminal electron accepting processes. The combined analysis of the microbial function, the affinity for substrates (H_2 and acetate) and the sensitivity for PCP toxicity by microorganisms might explain why electron transport chain has changed in soil biogeochemical redox process. Our study offers a comprehensive description of the impact of PCP on the soil microbial community structures, which could be very useful for understanding the regulation of soil nutrient and energy transfer during biogeochemical cycling processes in soils with significant inputs of exogenous pollutants.