Surface chemical properties of banded sea slicks

Abstract

Surface concentrations and film pressures of slick-forming organic constituents were measured in situ and on surface water samples from the Pacific Ocean, west of San Diego. The surface tension data, accurate to ±0·6 dyne/cm, indicated that film pressures ranged as low as a few dyne/cm in the banded slicks associated with internal waves. This observation is consistent with previously reported data which show that water-insoluble surface films damp capillary waves strongly at film pressures as low as 0·5-1·0 dyne/cm. Some surface-active material was present in all samples, whether from 'clean' rippled water or from visible slicks. Film pressures were measured as a function of the surface concentration of film-forming constituents. These data indicated that concentrations in many of the slicked zones were just sufficient to damp or resist the formation of ripples. This observation was also corroborated by the in situ surface tension data. It was estimated that a four-fold compression of the surface layer by horizontal convergent forces was required to create visible slicks at this location. © 1974.