I saw clumps of spume “raining” on the cliffs of Formentor in Majorca, Spain. They were lifted by the strong wind coming for offshore and dropping on the top of the cliff.
The foam is created by the agitation of seawater that contains higher concentrations of dissolved organic matter. The origin of that organic matter would be the breakdown of algal blooms.
The proteins, lignins, and lipids act as surfactants or foaming agents. The seawater is churned by breaking waves in the surf zone adjacent to the shore. The surfactants trap air in bubbles. The bubbles clump to each other through surface tension.