Scenario Simulations and Assessment

Once developed, we will use the modeling framework to investigate the interaction of oil with the ocean biogeochemical environment under several different scenarios. These include a hindcast of the Deepwater Horizon oil spill, similar deepwater releases under conditions that favor transport onto adjacent shallow shelves and coastal areas, oil spills occurring directly on the shelf, spills occurring during cold winter conditions, oil spills in the presence of low oxygen environments, and spills occurring during large river discharge and/or storm events.

Simulations of the Deepwater Horizon oil spill will be conducted prescribing physical fields from different time periods. Analyses of these simulations will be performed to address the question of how the impacts of the oil spill would have differed under alternate ocean current and wind (e.g., favoring transport onto the Texas-Louisiana shelf) or seasonal regimes. Simulations will also be performed emulating large oil spills occurring directly on the shelf. Each of these simulations, conducted to examine impacts of oil settling onto shelf sediments, will be initialized both with and without existing hypoxic conditions. Analysis of these simulations will address the questions regarding the differing rates of biodegradation over shelf and deepwater sediments for locally versus distantly released oil, and the impacts hypoxic conditions would have on biodegradation for oil settling on the shelf.

Finally, simulations will be conducted to explore scenarios in which enhanced concentrations of sediments are delivered to the region affected by the oil spill. These scenarios will include instances in which the plume from the Mississippi River extends over the affected region as well as simulations that are forced by strong extratropical and tropical storm events causing resuspension. The simulations will be analyzed to determine the role that enhanced sediment supply plays in determining oil deposition via flocculation, and the impacts this has on the biodegradation of oil in the sediments.