The amount of culturable bacteria detected in our study is similar to previous reports from the polar sites mentioned above.
Our plate counts were, however, AZD8055 research buy performed with frozen samples transported from Greenland to our laboratory in Denmark and we cannot exclude that this has affected the analysis negatively in comparison with plate counts based on fresh samples. Phylogenetic analysis of the most diluted MPN wells with polluted top soil and growing phenanthrene degraders showed the presence of strains related to Sphingomonas spp. and Pseudomonas spp. (Table 3). A community predominantly composed of Pseudomonas strains was apparent in wells with diluted polluted subsurface soil. Although it is not possible to conclusively link these clones to phenanthrene degradation, it seems likely that they played a role in the phenanthrene-based growth
detected in these MPN wells either by directly degrading phenanthrene or by indirectly feeding on exudates from the active degraders. Most 16S rRNA gene sequences from the wells had 98–100% sequence homology to bacteria isolated from either a cold and/or a contaminated find more environment. Interestingly, clones 13.1 and 13.4 from well 13 inoculated with diluted subsurface soil (Table 4) had the highest homology to Variovorax sp. 44/31 isolated from a hydrocarbon-contaminated Antarctic soil (Saul et al., 2005). This indicates that this strain, or a group of closely related cold-adapted hydrocarbon-degrading Variovorax spp., is widely distributed and proliferates in both Arctic and Antarctic areas affected by fuel spillage. A similar dominance of members of the genera Pseudomonas, Sphingomonas has been presented by Saul et al. (2005) in a study of hydrocarbon-contaminated Antarctic soils and by Eriksson et al. (2003) in a study of fuel-contaminated Canadian High Arctic soils. These genera
are known key players in other cold and temperate soils polluted with hydrocarbons and PAHs (Whyte et al., 2002; Eriksson L-gulonolactone oxidase et al., 2003; Aislabie et al., 2006; Labbéet al., 2007), which suggests a global distribution and potential proliferation in hydrocarbon-exposed soils. This study is the first to show an intrinsic bioremediation potential in hydrocarbon-contaminated Greenlandic High Arctic soils. We found evidence for the presence and potential activity of indigenous populations degrading at least some oil components in the polluted soils. These populations appeared to be phylogenetically related to others described from cold and/or contaminated environments. Our results, however, suggest that the very low ambient temperatures prevailing most of the year at St. Nord could be a restriction for the degradative activity even though competent degraders are present. This work was supported by the Carlsberg Foundation (funding for S.