70 years of helping people to care for our ocean

What is that foamy stuff on the beach?

By: Judy Mann

Many beach visitors noted lots of light brown foam on the beach yesterday and wondered where it came from. Well, this sea foam, also known as ocean foam or spume, is actually a very nutritious broth or soup of organic matter. Sea water is comprised of lots of different things including water, salts, and organic matter such as bacteria, plankton (tiny plants and animals), broken down bits of bigger plants and animals, animal poo and much more. Under turbulent conditions created by strong winds and waves – the ‘soup’ can get whipped up into a proteinaceous foam of air bubbles on the surface. This is nature’s way of filtering out organic matter from the water column onto the sea surface and from there it can wash up onto the beach.

At the uShaka Sea World aquarium we use specialised equipment known as protein skimmers, which look like enormous flasks that simulate this natural process. Our protein skimmers create tiny air bubbles that clean the organic matter out of the water in the same way.

Although it does not look that great, most sea foam is not harmful to humans. In fact, it is a sign that the ocean is filled with life. Sometimes however, the sea foam can have harmful effects on both humans and the environment, such as when harmful algal blooms (such as red tide) occur and decay near shore, or when the sea foam concentrates man-made pollutants. So, just to be extra sure, it is best not to play in the foam, especially close to industrial outfalls and pipelines.

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