Comparison of PAH degradation by autochthonous microbial communities in sediments of different Mediterranean port areas

PAHs are a class of organic compounds which by their nature (low volatility, low solubility, recalcitrance to biological degradation), tend to accumulate in marine sediments. This study investigated the natural PAH degradation by the autochthonous microbial communities present in sediments of three different Mediterranean tourist ports: Cagliari (Italy), El Kantaoui (Tunisia) and Heraklion (Greece). Bacterial populations able to degrade petroleum hydrocarbons are present in surface sediments from the port areas. Moreover, a spatial variation is evident among Heraklion port sectors according to their different uses. Microcosms were set up with the aim to evaluate aerobic and anoxic phenanthrene (Phe) degradation. The autochthonous microbial communities were able to almost-fully degrade Phe, in aerobic conditions, in 56 days, while in 120 days, no relevant degradation was found in anoxic conditions, except for Heraklion microcosms.