Fate of a tritiated Ekofisk crude oil in a controlled ecosystem experiment with North Sea plankton

An enclosed planktonic ecosystem was used to assess the environmental fate of a tritium-labeled Ekofisk crude oil. The flexible plastic enclosures were exposed to North Sea spring conditions. A dynamic model was developed, allowing calculation of vertical mass fluxes with depth based on actual concentration profiles and measured sedimentation rates. Adsorption and subsequent sedimentation of plankton and organic detritus may cause a rapid sinking of petroleum hydrocarbons. Microbial mineralization appeared to be negligible on a short-term scale.