GREAT SOUTH BAY - Environmentalists say they are concerned about thick foam that has been found in the water on Long Island's South Shore.

"The bay looked like a bubble bath on the Memorial Day weekend," says Marshall Brown, of Save the Great South Bay.

Carl Lobue, from the Nature Conservancy, explains the foam is the organic material left behind after last week's so-called mahogany tide - a sudden blooming of algae that is triggered by too much nitrogen in the water.

Marine scientists and environmentalists agree the excess nitrogen that causes Great South Bay's water quality problem comes from cesspools and lawn fertilizers. Some are calling on Long Islanders to stop using conventional fertilizers. They say doing nothing is not an option.

"Scientists say by 2030, we will lose all our fisheries, all our bays, and all our marshes," says Brown.