Foam in the aquatic environment

Foams are ubiquitous in the environment, commonly seen as discoloured patches on streams, rivers, lakes and sea water. They often are assumed to be anthropogenic in origin as they are aesthetically unpleasant, yet they frequently appear in pristine environments indicating a natural origin. In contrast to “hidden” chemical pollution, e.g. heavy metals, pesticides etc. the visibility of foam alarms the public.To derive more information on foam in freshwaters and marine ecosystems, a literature review was performed. Alongside with some basic considerations on the formation of foam, on methods to measure foam formation and on the legal aspects of foam on surface waters, the ecological importance of foam in the aquatic environment is discussed in this paper.

► This review paper deals with the occurrence of foam in the aquatic environment. ► Basic considerations on foam formation of foam are presented. ► Quantification methods for foam in emissions as well as instream foam are introduced. ► Legal aspects are discussed alongside with the ecological importance of foam.