The foam found in lakes and streams is usually natural. Wind-driven currents frequently create parallel streaks of foam in open water that accumulate along windward shores and in coves. Foam is created as decomposing plants and animals release organic compounds into the water. The compounds reduce the surface tension of water, causing bubbles to form. Many people blame shoreline foam on detergents, but detergents don’t create long-lasting foam since they quickly lose their sudsing ability.