'We have to do more': Study shows human activity plays role in intensifying red tide blooms over last decade

ANNA MARIA ISLAND, Fla. - The red tide bloom last summer killed hundreds of tons of fish a few months after 200 million gallons of waste water was spilled from Piney Point into Tampa Bay. 

"It was one of the worst red tides we had seen. It was different than normal because it started in the bay and progressed its way out which normally it starts south and works its way north," Captain David White with Anna Maria Charters said.

Red tide occurs naturally, but a study published in the journal Science of the Total Environment shows human activity has played a consistent role in intensifying red tide blooms over the last decade.

Dr. David Tomasko with Sarasota Bay Estuary Program joined with researchers from the University of Florida and the Sanibel-Captiva Conservation Foundation. They linked blooms in Charlotte Harbor and surrounding areas to nitrogen inputs from the Caloosahatchee River, Lake Okeechobee and areas upstream of the lake. 

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"The amount of nitrogen coming down the Caloosahatchee River will control how big it is. How long it will last and how intense it is," said Dr. Tomasko.

The study showed nitrogen loads can make red tide last longer, but it didn't connect nitrogen to starting red tide. 

"We have to do more than we have been doing lately, otherwise this beautiful bay that we are used to could slip away from us," said Dr. Tomasko.

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Studies into Piney Point and the red tide bloom that followed are still underway, but Dr. Tomasko said he and other researchers don't believe it was a coincidence. 

On the water, Captain White, who grew up on the local waterways, hopes changes will happen to keep the water crystal clear for generations. 

"Now that there is scientific evidence, actually showing that nutrients, phosphate, excess in the water from humans, hopefully there will be regulation and a better way to do it," he said.