MIAMI BEACH, Fla. — It’s being called the summer of sargassum.

Record breaking amounts of the ugly, foul-smelling seaweed have been washing up on South Florida shores for months.

Scientists are loudly sounding the alarm over what’s become a growing, stinky, unsightly, dangerous and costly problem.

“This is the new normal,” said Florida Atlantic University Harbor Branch research professor Brian Lapointe. “What we’re seeing here is truly a crisis.”

Sargassum is defined as a free-floating algae-like seaweed that drifts across the Atlantic and Carribbean oceans in massive mats, washing ashore in quantities unlike scientists have seen before, and it’s getting worse, already at more than 30 million tons.

“We have three more months of potential growth indicating that we could be seeing another record year this year,” said Lapointe.

Lapointe has tracked the spread of the brown seaweed since the Great Atlantic Sragassum Belt was first recognized in 2011. While sargassum has long been a natural part of the ocean ecosystem, the scale of today’s blooms is unprecedented.

“It stretches from the west coast of Africa across the tropical Atlantic, up through and around the Caribbean into the Gulf and the South Florida region,” he said.

For decades, scientists say sargassum has been fueled by nutrient-rich runoff carried into the Atlantic by major rivers, including the Congo and Niger in Africa, and the Orinoco and Amazon in South America.

“Deforestation in the Amazon, watershed and expansion of agriculture and fertilizer use,” said Lapointe. “All that runoff coming down and feeding Sargassum, particularly as these activities are affected by human activities.”

Rising global temperatures driven by the burning of fossil fuels is also supercharging the problem.

“It’s really a symptom of climate change and warming oceans and pollution building up in the ocean,” said Miami Waterkeeper CEO Rachel Silverstein. “And that together is causing these essentially blooms of algae.”

Using NASA satellite imagery, scientists are giving coastal communities a heads up on massive sargassum mats moving toward shore. Depending on where you are, the impact can vary widely.

Just because you don’t see mountains of sargassum on the beach doesn’t mean it’s gone.

Scientists say once the sargassum begins to break apart, the particles begin to sink below the surface and decompose on the bottom that can turn the water brown, and it can even deplete oxygen levels, increasing the risks for fish kills.

“At that point, it strips the oxygen out of the water and creates dead zones,” said Lapointe.

Just last week, fish kills were reported and documented on the ocean side of Key Largo.

“It really has a negative impact on water quality,” said Silverstein. “It’s coming ashore, it’s rotting, it’s causing increases in bacteria, it increases in nutrient levels that can have downstream impacts.”

As sargassum breaks down, it can add to elevated levels of enterococci, which is the bacteria used to measure fecal contamination in beach water.

High levels can force beaches to close.

“We’re seeing in many cases in South Florida, beach closures due to high levels of fecal indicator bacteria that are responding to the high nutrients,” said Lapointe.

And the costs are mounting, as millions of dollars have been spent on clean up, and millions more lost as tourists choose to stay away.

Because sargassum provides important habitat for marine life, state and federal regulations largely prevent large scale removal of sargassum at sea, leaving communities to deal with it once it reaches the shoreline.

Cities are already spending tens of millions of dollars a year to remove it, dispose of it, or bury it in the sand where it may actually be causing more problems.

As governments search for solutions to manage and repurpose the mounting seaweed, Lapointe says the problem won’t be solved on the beach.

It must be addressed at the source, by curbing nutrient pollution and reducing the greenhouse gas emissions warming our planet and ocean.

“If we do nothing, we’re going to continue to lose our natural resources,” said Lapointe. “The economic impacts are going to get worse as well as will the human health impacts. This is the new normal and like it or not, we’re going to have to adapt to it.”

And as the seaweed keeps coming, state and local officials are working with innovators to try and find scalable solutions to not just clean up the sargassum but to repurpose it and reduce its growing environmental and economic toll.

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