Response of bacterial soil communities to a small oil-spill at the Argentine base Jubany on King George Island (Antarctic)
In October 2009 an oil pipeline running from the fuel depot of Jubany base to the residential and laboratory buildings broke and caused an oil contamination of the ice and snow-covered surrounding. Four months later soil samples were taken in close and greater vicinity to the spill site as well as in the Potter Cove, however, due to snow and melt water runoff through the affected area sampling was limited. One year later snow did not cover the area. Sampling was repeated approximately at the same places and some additional sites. At the spill site the soil even in greater depth was still impregnated by diesel oil whereas at the other sampling points neither smell nor visual appearance of oil residues were noticeable. Correspondingly, the TC% values of the soil samples were very low except for those from the spill site. Measurements of the hydrocarbon content, however, will show how much oil was left. In order to find out if and how the spill affected the cold environment we studied 76 samples for changes in the bacterial community on the basis of the 16S rRNA gene by means of DGGE. Most of the samples showed a high bacterial diversity in 2010 as well as in 2011 with only marginal changes in the taxonomic structure during this period. In contrast, the diversity of the samples near the diesel spill site became clearly reduced. Some strong bands in the DGGE-gels indicated an enrichment of specific bacteria types. Clone libraries revealed that Actinobacteria together with a Betaproteobacterium prevailed in these communities and constituted obviously a natural autochthonous potential for crude oil bioremediation.