Marine oil pollution can result in the persistent presence of weathered oil. Currently, removal of weathered oil is reliant on chemical dispersants and physical removal, causing further disruption. In contrast few studies have examined the potential of an environmentally sustainable method using a hydrocarbon degrading microbial community attached to a carrier. Here, we used a tank mesocosm system (501) to follow the degradation of weathered oil (10 gl(-1)) using a bacterial consortium mobilised onto different carrier materials (alginate or shell grit). GCMS analysis demonstrated that the extent of hydrocarbon degradation was dependent upon the carrier material. Augmentation of shell grit with nutrients and exogenous hydrocarbon degraders resulted in 75 +/- 14% removal of >C-32 hydrocarbons after 12 weeks compared to 20 +/- 14% for the alginate carrier. This study demonstrated the effectiveness of a biostimulated and bioaugmented carrier material to degrade marine weathered oil. (C) 2013 Elsevier Ltd. All rights reserved.