Where Did All That Foam Come From?

Bill Foster
Watershed Educator

Foam piling up on Cayuga’s shores. (Courtesy of Allen’s Point residents and Network member John Fox.)

During the past summer, many Network members expressed concern over occurrences of unusually large amounts of white foam on the Lake. These events generally corresponded to stormy weather, and reports were concentrated on the east shore of Cayuga Lake. In researching the issue, Network staff learned that residents of Canandaigua Lake have had similar experiences with foam.

Foam is generally caused by agents called surfactants, which reduce the surface tension of water. When air is mixed with the water surface by wave or wind action, bubbles form. Laundry and other detergents have long been known to be a source of surfactants in lakes and streams. However, evidence is pointing in this case to an entirely natural source of these compounds. When organisms, such as algae, plants, fish and/or zebra mussels die and decompose they release fatty acids, which act as surfactants. Storms and agitation from boats cause these natural surfactants to mix with surface waters, resulting in streaks of sudsy white foam, which can collect in large quantities on windward shores, coves, or in eddies.

Research is indicating that a significant but temporary die back of Zebra Mussels has been occurring in some of the Finger Lakes, resulting in unusually high levels of surfactant compounds, which would account for the unusually heavy foam that appears periodically. The DEC, Cayuga County Health Department, and the Canandaigua Lake Watershed Program will be participating in further research over the coming seasons, and the Network will endeavor to keep you informed.

Editor's Note: Watershed partners are collecting information to better understand this phenomenon. You can help by reporting unusual foam occurrences to the Network! Email — educator@cayugalake.org.