Scientists go in depth to reveal the how and why of that sudsy substance streaking along Canandaigua Lake

The expanse of lake foam that recently resurfaced on Canandaigua Lake has people asking questions: What is it? What causes it? Can it make you sick?

Rest assured scientists are on it. Though we know more than we used to about this sudsy substance seen on Canandaigua and other lakes, it still remains a bit of a mystery.

“The good new is it’s not sewage,” said Professor John Hassett at SUNY College of Environmental Science and Forestry in Syracuse. Hassett specializes in organic chemicals in the environment.

Some have worried that the massive amounts of foam sometimes stretching for miles on the lake indicate foam-causing chemicals.

That’s not the case, either.

Research shows the foam results from natural sources that likely come from plants, said Hassett. Chemically speaking, the foam is comprised of fatty acids from plant sources. Some indications show the foam results from the breakdown of dead zebra mussels. While the foam comes from a breakdown of organic matter, when it shows up early in the summer season like now that belies or discounts the idea that its source might be from a die-off of plants, Hassett added.

Scientists have yet to nail down the exact cause, he said.

All freshwater lakes have some level of natural foam from wave action combined with organic matter that acts as a foaming agent, according to the Keuka Lake Association. Many people blame shoreline foam on detergents, but detergents don't create long-lasting foam since they quickly lose their sudsing ability. Natural foam has a somewhat earthy or fishy aroma. Detergent foam, in contrast, will have a noticeable perfume smell.

The "lines" of foam that occur are caused by "langmuir" currents, according to the association. “These currents are formed on the sides of wind-driven waves causing a 'funneling; action and the characteristic windrow of surface foam and other debris. The windrows will be more pronounced on a windy, southerly front.”

The foam itself is not hazardous to health or a concern for swimming or drinking water. But Hassett warned it can collect pollutants as it’s blown along the surface of the lake. So it's best to avoid getting it in your mouth.

Hassett said research will continue to learn more. “We hope to continue to do this on a curiosity basis,” he said. Students explore the subject, and a graduate student this fall plans to make the foam a subject of his thesis project.