Ah summertime. Time for gloom and doom, whether it be hurricane predictions, hot tub ocean temperatures, or the annual warning that the seaweed blob known as sargassum is looking to ruin your beach picnic when it comes ashore.
But fear not. Southeast Florida area beaches may again be spared, like last year, when there was a prediction of a huge bloom coming our way.
A new bulletin from the University of South Florida paints a grim picture. Current estimates suggest that there are around 37.5 million metric tons of sargassum involved in this latest bloom, more than 40% higher than the previous record set in June of 2022. Regional totals for the month of May are more than double compared to previous years. The authors of the study predict these totals to only increase in June and July as currents push the blob towards the Gulf of Mexico.
Despite some of these alarming numbers, current predictions are iffy on how much of an issue sargassum will be for, say, Key Biscayne or Miami Beach.
“It’s too early to say, and it appears unlikely, that [Southeastern] Florida will also receive a record-high amount of Sargassum,” said Dr. Chuanmin Hu, who helps lead the University of South Florida’s Sargassum Watch System. He cautions that scientists can’t say for sure Key Biscayne and Southeast Florida will be spared, “but we are running experimental forecasting models up to 4 days in advance.”
Currently, the USF report shows massive blooms off the coasts of South America, which have left most of the Caribbean.
Sargassum is a genus of free-floating brown seaweeds. Beachgoers know it for clogging up the white sands they seek and leaving a sulfur smell behind as it begins to decompose on the shore. It can play havoc for individuals with respiratory sensitivities, who can also face challenges from the rotting biomass that isn’t cleared away.
Sargassum inundation has become more of an issue for coastal communities and island nations as climate change and recent disturbances in atmospheric patterns have changed the way the algae flow around the Atlantic Ocean during their life cycle, scientists say.
Feeding on nutrient-rich upwelled water from the deep and supercharged by warmer oceans, the “Great Atlantic Sargassum Belt” has been a seasonally recurring phenomenon since 2011. Currents carry masses of the seaweed from the Antilles, up through the Caribbean, and past the Yucatan to eventually into the Gulf of Mexico. The Gulf Stream current can carry it past the Florida Keys and up into Biscayne Bay.
While healthy amounts of sargassum serve as a nursery for young marine life, heavy sargassum blooms can hurt seagrasses in Biscayne Bay and deprive the water underneath of oxygen. The sheer quantity of the biomass can also entangle sharks and other fish.
Key Biscayne monitors Sargassum patterns and outlooks from many different sources as part of the village’s resilience office. How bad a particular week will be for Sargassum can be difficult to predict depending on prevailing winds and currents.
If all signs point to high deposits, the Village can prepare its excavation crews. They will patrol the beach and scoop up as much seaweed as possible, before piling it centrally, and hauling it off the island to decompose.
According to its website, the Village’s first option is to rake the seaweed and bury it in a 3-4 foot pit. It is only during extreme conditions that the seaweed is loaded in trucks and transported to a landfill for disposal.
“We’re always on high alert during the summer. We’re constantly monitoring the winds and the conditions in advance and are prepared to respond as needed,” said Roland Samimy, chief resilience and sustainability officer for the Village.
This story was originally published in the Key Biscayne Independent, a WLRN News partner.
