Links between hydrocarbon-degrading microbial communities and soil characteristics on Macquarie Island

Links between hydrocarbon-degrading microbial communities and soil characteristics on Macquarie Island. Several sites associated with the storage and use of petroleum products on sub-Antarctic Macquarie Island have been contaminated with petroleum hydrocarbons. To assist with bioremediation of the sites, the microbial communities in these soils were investigated to determine whether hydrocarbon-degrading micro-organisms were present and to gain insight into which soil characteristics were shaping the communities. The structure of the microbial communities in both hydrocarbon-contaminated and non-contaminated soil was examined using DNA-based methods. The alkB gene was used as a marker for hydrocarbon-degrading bacteria and the 16S rRNA gene was used to examine the structure of the overall bacterial community. Genes for hydrocarbon-degradation were found at both contaminated and non-contaminated sites but the structure of the two communities was only correlated at sites where hydrocarbons were present at measurable levels. The concentration and type of carbon present affected both the whole community and the alkane-degrading community. In addition, the concentration and form of nitrogen was an important influence on the alkane-degrading community. This suggests that careful manipulation of nitrogen sources is required to select the most efficient hydrocarbon-degrading communities for bioremediation to be successful.