The Salish Sea, a cherished and biodiverse marine environment, is at risk for a major oil spill. Commercial marine traffic has been increasing, expanding the risk of a major oil spill from oil transport, as well as from bunker fuels from other vessels. Transport of diluted bitumen (dilbit), a type of heavy oil that can sink to the seafloor, presents unique challenges for protection of benthic habitats, those habitats that are restricted to the seafloor. 

A research report and maps published in the journal Continental Shelf Research and StoryMap describe this effort at identifying and mapping potential impacts of spilled dilbit in the central Salish Sea. Based on analysis of the geomorphology, sediment transport and deposition, and tidal influences, the work suggests how the sunken oil might behave in various locations — such as where the oil might become embedded into rocky crevasses, or be dispersed by strong currents, or accumulate and settle into sediments, or be trapped in bays. The maps also identify important benthic habitats that might lie in the path of spilled and sunken oil.