Artificial surface films in the sea area near Sylt1

Abstract

An artificial surface film of oleyl alcohol was produced in the North Sea off Sylt Island to investigate the chemical uniformity of the surface film and its influence on gas exchange. Oleyl alcohol concentrations found at the sea surface were in good agreement with previously calculated values. Significant differences between fatty acid concentrations before and after production of the artificial film indicated that the natural surface‐active substances were pushed aside by the spreading oleyl alcohol, with small amounts replenished from the underlying water later. The same displacement effect was inferred from the strong reduction in the number of colony‐forming units of organotrophic bacteria in the presence of an oleyl alcohol slick. Gas exchange, in this case desorption of CO 2 , was determined before and after formation of the artificial surface film. In the one experiment performed inhibition of exchange was significant when the film was present: without the film equilibrium was achieved after 3.7 min, whereas under the influence of the film, it took 5.7 min to reach equilibrium.