Recent tests in Canandaigua Lake suggest heavy foam buildup may be due to decaying zebra mussels. “In the past, residents along the eastern shore of the lake have noticed some foam wash up on their shoreline, but never to the extent that has occurred and is still occurring this year,” said Canandaigua Lake Watershed Manager Kevin Olvany. According to Olvany, in the past, the foam has been caused by pollution from phosphate detergents (from dishwashers and washing machines), and the natural breakdown of organic matter. The typical sources of organic matter in Canandaigua Lake are aquatic plants growing in shallow water, he said, as well as microscopic plants and animals throughout the lake.
But Olvany and Bruce Gilman, a conservation professor at Finger Lakes Community College, believe zebra mussels may be dying off in high numbers and producing the foam as they decay. When zebra mussels are plentiful, they eat microscopic plants, which improves the clarity of the lake. Tests by Olvany and Gilman show that the lake is not as clear as it was last year. This suggests zebra mussels are dying, perhaps because they have consumed their main food supply.
“We think natural breakdown of organic matter is the likely explanation (of the foam) this year, but we are still puzzled by the shear volume of it,” Olvany said. The foam, which appears throughout the lake and particularly on the east shore, is arranged by prevailing winds in streaks that can reach 30 to 50 feet wide and 4 to 5 miles long. “When it gets very windy, that’s when you see it,” said Sandy Beach resident Doris LaDonna. “We just can’t get over the amount of it.”
Testing in the lake will continue this fall and Olvany and Gilman plan to contact fellow North American researchers and those in Europe to determine if any other lake ecosystems have experienced similar levels of foam.