CONICET | Buscador de Institutos y Recursos Humanos

Hydrocarbon contamination in Antarctica deserves special attention for the ecological impact and the international conservation policies of the Antarctic Treaty protocol. In chronically contaminated soils the natural microbiota is adapted to the presence of the pollutant. Bioremediation processes may cause changes in those communities that need to be analysed before implementing full-scale processes. An in situ bioremediation assay was performed in mesocosms with diesel-oil polluted soil from Jubany station. Hydrocarbon concentration, viable counts, pH and soil moisture were measured. Significant hydrocarbon degradation occurred in all treated plots. Changes in structure of bacterial communities (T-RFLP analysis of amplified 16S-rDNA) in plots subjected to biostimulation and biostimulation plus bioaugmentation with two consortia were observed when compared with control. There was an increase in the evenness but no major variation in Shannon diversity due to the replacement of the main bacterial population by several different populations, which became abundant in treated soils. No differences were observed between biostimulated and bioaugmented plots; bacterial counts were the same and the T-RFs in consortia were not found in the soil plots profiles, being evidence that the consortia added could not establish. Several hydrocarbon degradation genes were detected by dot-blot analysis in all samples indicating the existence of a pool of catabolic genes in this contaminated soil. Detection of catabolic genes increased during treatment even in control plot and therefore the changes could not be attributed to bioremediation treatment. In conclusion, hydrocarbon bioremediation in treated mesocosms was successful and it resulted in changes in bacterial communities

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