I took my usual weekend stroll along the strand (Del Monte Beach in Monterey, California) today.

It was different today than ever before.

For one thing, there were no Sandpipers or Plovers or Gulls on the beach. Perhaps that was because it was pretty windy. There were gulls and pelicans flying overhead, but none landed on the beach.

But there was something else stranger and possibly disturbing: the surf was very sudsy; it was as if somebody had dumped tons of Mr. Bubble into the Bay. The edges of the surf (left behind after the waves) looked just like a bubble bath. The wind was blowing pieces off the sudsurf that looked like what you get when you blow the sudsy bubble bath foam off your hand, and the pieces went blowing along the beach like coastal tumbleweeds.

Is this a known phenomenom? I've never seen it before...


4 Answers 4


The suds are caused by protein. Protein is usually consumed by the nitrogen cycle and finally plant life, but if there is enough water churning by wind and white caps and breaking waves it can froth up and dry out and get blown away and get trapped a gyre where is eventually melts back down into the water. Sometimes it gets blown into a beach as you've seen.

Oh and by the way, it's completely natural, not something to be concerned about.

  • it's completely natural but pollution can cause algal blooms which can increase the amount of this
    – user2766
    Commented Jul 25, 2016 at 11:02

Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter (including proteins, lignins, and lipids) derived from sources such as the offshore breakdown of algal blooms.
-- Wikipedia (2016-07-25): Sea foam

Human waste can be a source as well.

The lack of wildlife could be explained by their food sources being covered in possibly irritating or infectious foam.


Sea foam is from diatoms breaking up (unless it is from pollution). Normally, it is from diatoms, which are a form of plankton that have a glass-like silica shell (also their broken shells make diatomaceous earth). When their shell breaks, it mixes with the water and makes sea foam!


An interesting article from The National Oceanographic and Atmospheric Administration Research lists causes of sea foam, most of which have been covered by all your other answers. It does say that the formation of sea foam varies by different coastal regions.

While in general, sea foam is considered safe to humans and birds, and even beneficial, there have been instances where algal blooms can be harmful. This paragraph is relevant, especially since it mentions the California coast, but I'm not saying you are, or have ever, witnessed these potentially negative effects.

Most sea foam is not harmful to humans and is often an indication of a productive ocean ecosystem. But when large harmful algal blooms decay near shore, there are potential for impacts to human health and the environment. Along Gulf coast beaches during blooms of Karenia brevis, for example, popping sea foam bubbles are one way that algal toxins become airborne. The resulting aerosol can irritate the eyes of beach goers and poses a health risk for those with asthma or other respiratory conditions. Scientists studying the cause of a seabird die-offs off California in 2007 and in the Pacific Northwest in 2009 also found a soap-like foam from a decaying Akashiwo sanguinea algae bloom had removed the waterproofing on feathers, making it harder for birds to fly. This led to the onset of fatal hypothermia in many birds.


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