It knocked Bill Baggs Cape Florida State Park off the best beaches list. The Key Biscayne Village Council appealed to the state for help. Miami-Dade County marshaled a team to be at the ready.
But the 5,000-mile-long, 12-million-ton belt of sargassum never materialized on the beaches of Key Biscayne or much of Florida.
And scientists are baffled.
Key West got its fair share of sargassum, but tons of the brown seaweed that many feared would be decaying on South Florida beaches in June simply floated elsewhere. The hotspot at the moment is the eastern Caribbean.
“Nature is very complex. Most of the time history repeats,” said Chuanmin Hu, professor at the Optical Oceanography Laboratory at the University of South Florida in Tampa.
“But not this year. Something unusual happened but we don’t know why yet.”
The amount in the Gulf of Mexico decreased in June by 75 percent, which the Center called “beyond expectation.”
Fueled by nutrient runoffs and “climate variability, large amounts of Sargassum seaweed have appeared in the Caribbean since 2011, Hu’s lab has found. Although it serves as a habitat for some marine life, excessive seaweed can pose environmental, ecological and economic problems for Florida coastal municipalities – and headache on how to dispose of it.
In 2019, after Key Biscayne beaches were closed because of a bacteria associated with sewage, the Village commissioned a University of Miami study. It wasn’t feces – but high amounts of sargassum that was the active source of the same bacteria.
The Village has spent more than half a million dollars a year to wrestle with sargassum while partnering with the county. Last year, the village removed about 7,500 cubic yards or 450 truck loads.
Some companies want the seagrass to turn into supplements and some research shows the biomass can be utilized as a source for biofuel.
Even the threat of sargassum has affected the reputation of Key Biscayne area beaches. Years ago, it knocked Bill Baggs from consideration from the Top 10 list of America’s best beaches compiled by FIU professor Stephen Leatherman – known as Dr. Beach.
Bill Baggs, a state park, does not remove sargassum that comes ashore.
The Village in April asked for help from the state Legislature for the coming seaweed storm. To be clear, there was evidence of a coming sargassum invasion, although scientists cringe at the word ‘blob.’
The mystery is — what happened?
The Optical Oceanography Laboratory tracks sargassum blooms using satellite images. It has released a monthly report during peak season since 2018.
And this year looked like a doozy.
“In March, the amount of sargassum within the belt presented a historical record – higher than any years before in the same month,” Hu said. “If history were to be repeated, then by June the amount would be outrageous.”
But that didn’t happen and Hu and his researchers are trying to find out why. Right now, he only has a hypothesis.
“My speculation is that in June, we had stronger winds,” Hu said. “Due to storms or due to atmospheric circulation, the winds were stronger this time of year.”
Right now the prediction from the center is for sargassum to stay away from Florida for the rest of summer.
“By the end of June, there is very little sargassum in the Gulf of Mexico and western Caribbean Sea, which should be good news for many coastal residents in those regions,” according to the center’s report for June.