South Florida counties gear up for stinky seaweed season

Sargassum making its annual voyage to South Florida’s shorelines, threatening tourism and coastal ecosystem

MIAMI-DADE COUNTY, Fla. – Large patches of what will become stinky shoreline seaweed, stretching from the west coast of Africa to just off the southern cost of Cuba, are making their way to South Florida and local leaders are getting ready.

Local 10 News Photojournalist Curt Calhoon recently spotted sargassum, surface floating patches of brown micro algae, off the deck of a ship cruising through the Caribbean.

Brian Barnes is one of the University of South Florida researchers tracking a bloom via satellite.

“We call it the great Atlantic sargassum belt,” Barnes said. “They range in size from a handful to a square mile.”

In the ocean, it serves as a floating nursery for a variety of marine species.

The problem happens when it comes on shore. If not cleaned up properly, it can shade out corals and sea grass and create near-shore dead zones as it decays.

“It uses up all of the oxygen in the area and you can get a dead zone,” said Barnes. “As it decays, it can fall in the weather column and straight smother those ecosystems.”

As it starts to decompose, the sargassum releases hydrogen sulfide, which smells like rotten eggs.

“Some people with asthma may have some respiratory issues, but not the broader population,” said Barnes.

Miami-Dade County Mayor Daniella Levine Cava said the county will gear up as needed.

“We have a contract in place with a company that is removing sargassum from some of the hot spots,” she said.

Researchers who have been tracking the steady annual increase in sargassum say there are a variety of factors at play regarding why the naturally occurring micro algae is blooming patches upwards of a square mile in size, from warming seas to oceans rich in nutrients like human sewage and fertilizer run-offs from the world’s rivers into the sea.

“Definitely we are on alert and making sure there should be an increase -- our current cost is $3.9 million per year for the contract,” said Levine Cava. “We do have requests for support from state and federal sources, so we are gearing up to bring attention to the fact that we do need help.”

Sargassum season typically runs from May to October, the same window as sea turtle nesting season.

“Every day, there are people looking for where nests might be, marking off those areas, making sure they are not disturbing any nests while cleaning up the sargassum,” Levine Cava said.

In Monroe County, officials said they are planning for twice-daily cleanings.

About the Author:

Christina returned to Local 10 in 2019 as a reporter after covering Hurricane Dorian for the station. She is an Edward R. Murrow Award-winning journalist and previously earned an Emmy Award while at WPLG for her investigative consumer protection segment "Call Christina."