Bright blue patches of decaying algae are floating on top of the water at Sovereign Yacht Sales along the St. Lucie River near Stuart.
"They started discharges again. I guess the wind is right and it’s just kind of pooling in here, looking real bad," said Tom Cubr, a broker for Sovereign Yacht Sales, which is just southeast of the Palm City Bridge.
Cubr said the water in the marina had green algae in it back in 2016, but he never saw it turn blue like it did in other marinas at the time, such as Central Marine downstream.
"It seems to be worse. I don’t remember seeing the blue-green of the blue-green algae, specifically the blue," Cubr said. "Now we’re seeing a lot of that and that’s the nasty stuff, the bad stuff."
Malcolm McFarland, a researcher at FAU Harbor Branch, said algae dies when it runs out of nutrients in the water. It changes color and turns blue as it dies, much like how leaves change color when they die in the fall.
McFarland said bacteria will then eat the dying algae, which is actually what releases the infamous pungent smell.
"I happened to be on a boat yesterday and I was really startled with the smell out there," Cubr said. "Rancid decay.”
McFarland said just because algae are dying and turning blue in one small part of the water, it doesn't mean it's going to happen everywhere. The water has to run out of nutrients for the algae to decay.
"We’ve been to city hall. We’re definitely proactive. We’re definitely concerned," Cubr said.