Bacterial community dynamics during multi-year bioremediation of oil-contaminated soil in a boreal climate

Here we describe the dynamics ofbacterial community inresponse to used motor oil contamination and perennial crop cultivation in a boreal region, using 16S rRNA gene sequencing of field soil samples collected at the beginning of the growing season in four years (2009-2012) from each plot. Our objective was to determine whether there were significant changes in the bacterial community i) in oil-contaminated soil in regard to non-contaminated control soil and 2) under different cropping systems (pure fodder galega, pure brome grass, galega-brome grass mixture) in regard to bare fallow control over time. Based on non-parametric multivariate analysis of community data, we observed significant time- and oil-dependent succession in soil bacterial community. Crop cultivation had small impact on bacterial community after crops achieved stable growth.