Lake Foam

Lakeshore property owners often become concerned about foam that is observed along the shore, in coves, or as parallel streaks in the open water. Foam is created when the surface tension of water (the attraction of water molecules for each other, which gives a drop of water its round shape) is broken down by surfactants, and then air is introduced by the turbulence of waves, causing bubbles to be created. 

While the foam that washes up on shore may look like the foam in your kitchen sink, lake foam is usually a naturally occurring phenomenon and not typically caused by detergent or soap. When it first appears, lake foam can be white, but generally turns brown over time. The foam will persist for some time gradually diminishing in size. Lake foam will smell earthy or fishy whereas foam from detergents generally will be white and sweet smelling or scented.

Lake foam is created when naturally produced organic surfactants are released from algae and plants when they die and begin to decompose. These organic surfactants are part of a large variety of plant material that when dissolved in water is referred to as dissolved organic carbon (DOC). The primary source of DOC in lakes and streams is from the surrounding watershed. 

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