The role of coral mucus in reducing the wind drag over coral reefs

The surprisingly small wind stress on the water over a fringing coral reef, which was observed by Hicks et al. (1974), raised the question as to whether this was mainly a shallow water effect or could be the effect of a surface film of organic surfactant. This is considered in relation to other evidence on the shallow water effect and to the fact that coral secretes mucus containing much cetyl palmitate (Benson and Muscatine, 1974). On hydrolysis this yields two powerful surfactants of a type found in natural sea slicks, so the surface film effect is concluded to be the predominant influence.It is conjectured that mucus secretion may have a role in reef ecology by producing quieter water conditions for the more delicate forms of coral typically found some distance shoreward of the windward reef edge.