In situ bioturbation and hydrocarbon fate in an experimental contaminated Mediterranean coastal ecosystem

An in situ experiment was conducted in the French Mediterranean littoral (Gulf of Fos) from July 1992 to January 1993 using cores containing defaunated or natural sediment. Particulate tracers (luminophores) and hydrocarbons (Arabian Light crude oil) were deposited at the sediment surface. After 1, 4 and 6 months, luminophore and hydrocarbon (saturated fraction) distribution patterns in the sedimentary column were studied. After 6 months, in presence of bioturbation, 23.7 % of the luminophores and 14.2 % of the hydrocarbons initialy deposited were buried, down to depths of 10 cm and 6 cm depth respectively. Hydrocarbons were biodegraded both at the surface and within the sediment.