Metagenomic and geochemical characterization of pockmarked sediments overlaying the Troll petroleum reservoir in the North Sea

454 sequenced metagenomes from sediments sampled 5-20 cm bsf. Five samples were taken from the pockmarked sediments overlaying the Troll petroleum (oil and gas) reservoir in the northern North Sea. sediment samples from four pockmark samples and one sample from the Troll plain were sequenced. Two samples were taken from the outer part of the Oslofjord, Norway. Presence of thermogenic hydrocarbons is this area is unlikely. The aim of the study was to characterize the taxonomic distribution and metabolic potential of the prokaryote communities inhabiting the Troll sediments, both in general and related to possible thermogenic hydrocarbon degradation. Further, we have investigated whether there was an increased potential for methane oxidation or other microbial processes, supporting seepage in pockmark sediments, or if analyses of the microbial communities would agree with the geological analyses indicating no active hydrocarbon seepage from the pockmarks at the present time. The two Oslofjord sediments were used as references regarding thermogenic hydrocarbon influence.