Mineralization of [14C]phenanthrene to 14CO2 was measured in contaminated soils at temperatures down to 0 °C and sizable naphthalene-, undecane-, biphenyl- and phenanthrene-degrading check details populations were measured by microplate-based most-probable-number analysis. Cloning and 16S rRNA gene sequencing, focused on the dominant phenanthrene-degrading bacteria, revealed strains related to bacteria previously found in cold and contaminated environments. Overall, we provide evidence

for the presence and potential activity of phenanthrene-degrading bacteria in polluted St. Nord soils and this study is the first to indicate an intrinsic bioremediation potential in hydrocarbon-contaminated soils from the Greenland High Arctic. The Arctic warming and the reduction in the polar ice sheet during the last few years (Graversen et al., 2008) will boost human activity in the High Arctic regions of Greenland. This will inevitably lead to increased inputs of anthropogenic compounds and the issue arises as to whether an intrinsic attenuation

potential is present in these areas. Intrinsic remediation of petroleum hydrocarbons under cold conditions have been indicated before (Bradley & Chapelle, 1995; Aislabie et al., 1998; Rike et al., 2005) and contaminated alpine, Antarctic and Arctic soils may harbour hydrocarbon-degrading populations (Margesin & Schinner, http://www.selleckchem.com/products/FK-506-(Tacrolimus).html 2001; Rike et al., 2003; Saul et al., 2005; Aislabie et al., 2006). In some cases, however, the natural attenuation potential present in these cold environments is insufficient to clean up soils within a reasonable time and active bioremediation approaches have been suggested (Filler et al., 2001; Margesin & Schinner, 2001). Studies on contaminant degradation in High Arctic regions have until now addressed areas in Alaska (Bradley & Chapelle, 1995; Filler et al., 2001), Canada (Whyte et al., 2001) and Svalbard (Rike et al., 2003, 2005), but no studies have focused on the Greenland

High Arctic. Previous studies have mainly focused on the fate of easily biodegradable oil fractions, whereas knowledge on the biodegradation Progesterone of polycyclic aromatic hydrocarbons (PAHs) in Arctic regions is lacking. Station Nord (St. Nord) is a military base operated by the Danish army located at 81°36′N and 16°40′W approximately 500 miles from the geographical North Pole. The area is an Arctic desert with an average annual air temperature of −14 °C and <100 mm annual precipitation. The temperature can reach 16 °C during the summer period and down to −50 °C during the winter. St. Nord is a gateway to the national park in the northern part of Greenland as well as the North Pole and the storage and handling of fuels have led to accidental spillage. In addition, St.