This invention is a system and method for bioremediation of hydrocarbon and organic pollution in fresh and salt water. Hydrocarbon and organic pollution digesting microbes are placed in a floating carrier where the microorganisms are exposed to the pollution and the pollution is digested. The floating element may be a block of polymeric foam. The microbes may be supported on powder such as clay minerals, and the powder may be formed into pellets held in slits in the foam.