The U.S. Coast Guard Research and Development Center RDC undertook a Research and Development R and D effort to identify and develop technologies or techniques that can mitigate the impacts of oil in the water column on the surrounding environment through containment, diversion, or removal of the submerged oil. It was a part of a larger effort in the CG R and D program to develop countermeasures and cleanup technologies for a range of oil spills. This report summarizes the results of Phase II-B Prototype Development and Demonstration. This phase of the project involved demonstrating two mitigation approaches at the National Oil Spill Response Research and Renewable Energy Test Facility Ohmsett in Leonardo, New Jersey for their feasibility and performance. Argonne National Laboratory ANL developed a method to treat polyurethane foam, a commonly used material, to adsorb submerged oil. Prior to use, the foam undergoes a series of chemical processes in order to render it oleophilic and thus more susceptible to adsorbing and retaining oil droplets and dissolved oil in the water column. Dynaflow, Inc. developed amicrobubble flotation system, capable of being towed behind a vessel that is designed to remove neutrally buoyant oil droplets from the water column using microbubble injection with DYNASWIRL bubble generators. Both systems show some promise for mitigation of oil in the water column but need further development before they can be recommended for field testing. This study was funded in part by the U.S. Department of the Interior, Bureau of Safety and Environmental Enforcement BSEE through Interagency Agreement E14PG00028 with the United States Coast Guard Research and Development Center.