Miami Beach wrestles with a new and unwelcome visitor: Seaweed — foul piles of it

The famed sands of Miami Beach that have lured models, tourists and celebrities for decades are now drawing a frequent visitor that nobody wants: seaweed, foul-smelling mountains of seaweed. Some days in the last few weeks, there has been so much drifting ashore that it blocks swimmers from entering the water in some stretches

The foul-smelling brown stuff that piled up on South Florida’s shores in the past few years is again washing up along the coast and some beachgoers are fed up. Miami Beach residents are pressuring Miami-Dade county to come up with a plan to remove the slimy nuisance, formally known as sargassum.

“We have been suffering the consequences of this sargassum for more than three years; our properties are being devalued, our quality of life is being impacted and tourism in Miami Beach will suffer if this continues,” resident Arsenio Milian said to city and county officials at a Miami Beach Community Affairs Committee meeting earlier this week.

Scientists say it’s not a question of whether it will continue, but how bad it will be: worse or just slightly better than last year’s record-breaking crop. While sargassum is a natural occurrence, traditionally washing up on beaches in the Caribbean, Gulf of Mexico and Atlantic Ocean shorelines, it has only become a major issue over the past few years. It’s not a marine life mass killer like red tide or potentially toxic as algae blooms, but it’s annoying for tourists and beach lovers.

In Florida, large brown mats of seaweed started showing up in 2011, after an unusual pattern of winds and surface seawater circulation took place in late 2009 and early 2010 in the Sargasso Sea, in the Atlantic. Since then, mass seaweed beachings in Florida, in the Caribbean and Gulf of Mexico, in Western Africa and as far south as Brazil have been frequent, leading scientists to connect the sargassum explosions to rising ocean temperatures and increasing amounts of nutrients from fertilizers that flow into the ocean.

Plumes of nutrient-laden water from the Amazon and Mississippi rivers have also fueled the sargassum blooms off South America and in the Gulf of Mexico, where the Loop Current, a warm ocean current that flows northward between Cuba and the Yucatan Peninsula, carries the seaweed through the Florida Keys and onto the state’s east coast.

“There has been a huge increase in fertilizer use, and an increase in rainfall as a result of climate change,‘’ said Brian Lapointe, a biologist at Florida Atlantic University’s Harbor Branch Oceanographic Institute, who has studied the seaweed for 40 years. “That combination is exacerbating the sargassum blooms and affecting the ocean ecosystem as a whole.’’

Last year and 2015 were particularly bad years, especially in the Caribbean. This year, Mexico is struggling to deal with the deluge that has led to mass cancellations at popular vacation spots such as Cancun and Playa del Carmen. Last week, the state of Quintana Roo, where the beaches are located, declared a state of emergency to more easily access federal funds to clean up the rotten-egg-smelling mess.

This year, Florida could again experience large amounts of sargassum, even if not at record levels.

“Because the amount of sargassum in the Central West Atlantic in May this year was lower than in May 2018, readings in the June-July period may also be lower,’‘ said Chuanmin Hu, professor of optical oceanography at the University of South Florida. His lab tracks seaweed movements based on NASA and NOAA satellite images. Quantities will still be higher than most of the previous sargassum years, he said.

Miami Beach residents have had enough. This week they called on the county, which is responsible for beach maintenance, to remove nasty stuff that’s been keeping people out of the ocean. Currently, seaweed isn’t removed from the beaches because of efforts to protect marine turtles and because of its value in fighting beach erosion.

Lee Hefty, who runs the county’s Division of Environmental Resources Management, said 2019 could be another bumper crop year for sargassum. He said Miami-Dade will “use an adaptive management approach going forward’’ to explore new solutions to manage the nuisance.

Miami-Dade maintains 17 miles of beaches, including 7.5 miles in Miami Beach. To manage the seaweed across its beaches, the county uses tractors to cut and turn the seaweed on a daily basis, at a cost of $4.4 million per year.

Maria Nardi, county director of the county’s parks department, presented possible options and showed that partial removal of the seaweed could cost $35 million in the first year. Total daily removal would cost about $45 million per year, she said. And it’s not just a question of paying contractors to haul the stuff away; Miami-Dade would need permits from the Department of Environmental Protection to go through with removal.

“I don’t understand why we’re delaying this,” said Anamarie Melo, president of the Mid-Beach Neighborhood Association. She said residents have complained about respiratory problems and are blaming the sargassum. ”This is a true health and safety issue and I hope we can make it a priority.”

There is no evidence that the seaweed itself causes health problems. However, as it decomposes once it piles up on the sand, it could potentially cause skin irritation, said Lapointe. And because sargassum harbors other marine life like jellyfish and the stinging Portuguese Man-o-war, it’s not a good idea to swim through thick mats.

But sargassum is a key part of the marine ecosystem. It supports a menagerie of marine life: crabs, shrimp and small fish who serve as prey for Mahi-Mahi and other commercially valuable fish. For juvenile sea turtles, sargassum can provide food and refuge from predators in their first years of life, after they make their way from the sandy beaches where they were born to the ocean.

“In small quantities, it’s actually kind of good,” said Stephen Leatherman, director of the Laboratory for Coastal Research at Florida International University, known as “Dr. Beach’’ for his reviews of coastal areas. “It can be used to fertilize the dunes, but in huge quantities it becomes a problem.’’