Airborne infrared imagery collected over the ocean reveals slicks that are 0.1¿ to nearly 0.4¿C cooler than the surrounding water surface. These thermal contrasts are analyzed within a framework of surfactant--turbulence interaction. Slicks are shown to be a potential source of error in the remote retrieval of sea surface temperature, but a slick's thermal contrast is also a potential source of information about the ambient thermal boundary layer.