Increased oil spill preparedness for Scottish deep waters – the role of sediments in a deep water oil spill

Supervisors: Prof Ursula Witte (University of Aberdeen), Dr. Alejandro Gallego (Marine Scotland Science) and Professor Jim Anderson (University of Aberdeen)

Oil releases can produce significant environmental consequences, and with exploration ongoing in progressively deeper waters, a greater need arises to understand the consequences of releases in deep water environments in order to improve monitoring and optimize response measures after a spill. A large proportion of Scottish waters are deeper than 200 m, and hydrocarbon (HC) extraction now occurs down to 1100 m in the Faroe Shetland Channel (FSC), but there is currently little baseline information for deep water ecosystems, and no systematic monitoring plan. During the Deepwater Horizon oil spill, naturally occurring HC degrading bacteria (HDB) played an important role in reducing the overall environmental impact of the spill. Nevertheless, and despite comparably sluggish circulation, an area of almost 150 km2 of seafloor was significantly impacted by oil. In contrast to the warm Gulf of Mexico with its natural HC seeps, HC degradation rates in subzero deep FSC waters can be expected to be significantly lower, and its coarse sediments are likely to efficiently filter and accumulate HCs dispersed or dissolved in bottom-near waters where they can persist for decades, entering the food web and triggering prolonged ecotoxicological effects.
This project will assess the entrainment, mobility, degradation and persistence of HCs in FSC sediments. Experiments will be designed in close collaboration with SINTEF to facilitate comparison of results with those of OSCAR (one of the most advanced commercially available oilspill modelling packages), and eventual model improvements.