Isotherms of natural sea surface films: A novel device for sampling and properties studies.

A double-walled submersible sea surface film sampler which ‘‘cuts out’’ an undisturbed film-covered area has been built for force-area isotherm studies of untreated water samples. Preliminary results on static and dynamic surface properties of naturally formed films present in coastal zones of the Baltic Sea are presented and discussed in reference to water samples collected in a bottle (depth of 20 cm) at the same site and time, which in turn significantly differ from each other. The new sampler also allows a few statements of oceanographic relevance on the film homogeneity (i.e., film filling factor) and the energy transfer through surface films from isotherm hysteresis measurements. [ABSTRACT FROM AUTHOR]