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Everglades Foundation Scientists Confirm Link Between Red Tide and Polluted Discharges from Lake O.

For Immediate Release October 4, 2018

Everglades Foundation Scientists Confirm Link Between Red Tide and Polluted Discharges from Lake Okeechobee

Phosphorus and nitrogen from agricultural runoff is main culprit; Lake Okeechobee discharges that cause blue-green algae also “feed and sustain” red tide

Palmetto Bay, Fla. — Discharges of phosphorus- and nitrogen-laden water from Lake Okeechobee “feed and sustain” red tide outbreaks that now afflict both of Florida’s coasts and “almost certainly” are the cause of blue-green algae, according to scientists at The Everglades Foundation.

“In South Florida, our problems are not just limited to red tide,” observed a group of scientists from The Everglades Foundation in a report issued today. “We also have blooms of blue-green algae stretching from the St. Lucie estuary on the east coast, across Lake Okeechobee and over to the Caloosahatchee estuary on the west coast.”

The two problems are related, since “the lake’s contributions to the blue-green algae problems on the west coast are likely helping to sustain red tide in coastal waters outside the Caloosahatchee,” the Foundation’s scientists assert.

While red tide was first observed by the Spanish in the 1500s, “it needs a supply of nutrients to sustain itself, and that is where modern pollution from Lake Okeechobee comes in,” the report continued. “Discharges from Lake Okeechobee likely provide a local source of nutrients that are sustaining this bloom as it has moved closer to shore.”

Unlike red tide, the blue-green algae observed in the Caloosahatchee and along the Indian River “is almost certainly caused by releases from Lake Okeechobee,” in addition to being sustained by them, the Foundation’s report said. “Scientists studying the stresses on the planet agree that excess nitrogen and phosphorus are among the most pressing issues facing the planet…(with) more than 75 percent of the planet applying unsustainable levels of phosphorus to the landscape.”

The Foundation’s report cites modeling by the Florida Department of Environmental Protection that, in the long term, about 60 percent of the nitrogen and 45 percent of the phosphorus in the lower Caloosahatchee comes from Lake Okeechobee, with the remainder is caused by local urban and agricultural sources. A 2014 study established that phosphorus and nitrogen from the Caloosahatchee River are a “significant source” of the red tide bloom in nearshore areas and the lower estuarine zone.

The Foundation is sponsoring a $10 million innovation award, the “George Barley Water Prize,” to find a safe, effective and affordable technology to remove excess phosphorus from fresh water supplies, the report notes.

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About The Everglades Foundation The Everglades Foundation is a 501(c)(3) non-profit dedicated to leading efforts to restore and protect the greater Everglades ecosystem. Since its founding in 1993 by a group of local outdoor enthusiasts, the Foundation has become a respected and important advocate for the sustainability of one of the world’s most unique ecosystems. For more information, please visit


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