Officials have had to remove thousands of tons of sargassum from Florida\u2019s beaches amid the climate crisis<\/p>\n
Dealing with seaweed is the bulk of Chris Bumpus\u2019s job during the summer. As chief of conservation for Miami-Dade county\u2019s parks, recreation and open spaces department, Bumpus is in charge of cleaning sargassum off 17 miles (27km) of county beaches. But some days, the odds are stacked against him and his team.<\/p>\n
More and more sargassum, a kind of floating brown algae, has been washing up on the beaches of south Florida, west Africa, the Gulf of Mexico and the Caribbean.<\/p>\n
Most mornings this time of year, a member of Bumpus\u2019s seaweed crew walks on to South Beach around 7am to take pictures of piles of the stemmy, spicy-mustard-colored seaweed before a dozen tractors and specialized beachcombing vehicles are put to work trying to integrate the sargassum into the sand or rake it out to be hauled away. \u201cBack in July, the beach looked clean for about an hour,\u201d Bumpus said. That month alone, 9,000 tons of seaweed were removed from Miami-Dade county beaches, more than ever removed in a single month before.<\/p>\n
\u201cHopefully, by October it will die down,\u201d he said. \u201cJuly is always the worst. It\u2019s been a heavy season.\u201d<\/p>\n
Before the cleanup begins, a crew has already marked any new sea turtle nests so they aren\u2019t harmed by the sargassum removal. The county holds a permit with the Florida department of environmental protection for its employment of heavy equipment to corral the seaweed. The permit prohibits that equipment during turtle nesting hours, from 30 minutes before sunset until sunrise. So far this nesting season, about 700 sea turtles have built nests on county beaches.<\/p>\n
Miami-Dade county spends $3m per year on sargassum removal, more than any other county in Florida, Bumpus said. The Florida Keys, however, can see heavier accumulations of sargassum because of the inlet-like shape of their beaches, he said. For centuries, sargassum has grown in the Sargasso Sea, a region of the north Atlantic encircled by ocean currents that keep the seaweed concentrated there. But in 2011, scientists saw the Great Atlantic Sargassum Belt form for the first time, stretching from west Africa to the Gulf of Mexico. Scientists say several factors contribute to the blooms, including nitrogen and phosphorus from rivers \u2013 such as the Amazon, Congo, and Mississippi \u2013 warmer water temperatures and ocean circulation.<\/p>\n
Since 2011, the amount of sargassum has doubled every five years, as a result, larger and denser mats of sargassum have been washing up in Mexico, Florida and the Caribbean. This summer, satellite imagery showed the second highest amount of sargassum in the Great Atlantic Sargassum Belt at a whopping 33.5m tons, slightly behind 2025 when the seaweed biomass reached 38m tons.<\/p>\n
The climate crisis has also played a role in the proliferation of sargassum, said Brian LaPointe, a research professor at Florida Atlantic University Harbor Branch, who has been studying sargassum since 1982. \u201cAs we see more ocean warming, we get more evaporation and that drives these extreme rain events that essentially flush more nutrients from land into the ocean,\u201d he said. \u201cSo that\u2019s an indirect effect that can increase nutrient supply to sargassum.\u201d<\/p>\n
Miami-Dade county first began efforts to address its seaweed problem in 2019. The county\u2019s annual seaweed removal budget is funded by tourist development taxes paid by visitors who stay at hotels and short-term rentals. In July, Miami-Dade county commissioners voted to petition the state to allow the county more flexibility to use beach raking equipment in more areas.<\/p>\n
\u201cI think this year has been kind of a gamechanger in that we\u2019ve seen major inundations here in south Florida, more than we\u2019ve ever really seen in past years, and comparable to what\u2019s been happening in the Caribbean, Mexico and the Dominican Republic,\u201d LaPointe said.<\/p>\n
In Mexico, President Claudia Sheinbaum announced a $115m national plan to combat sargassum, including employing ships that scoop the seaweed out of the water. But federal and state agencies in the US prohibit sargassum removal in open-water because of concerns for the sea life that lives in the floating seaweed mats. But LaPointe said that could eventually change, as research in his lab is showing that sargassum loses much of its marine life as it deteriorates and approaches the beach.<\/p>\n
Sargassum serves as a critical habitat in the open ocean, but that changes as it gets close to and comes ashore. \u201cWhat we\u2019re seeing is that as this excessive amount of sargassum comes ashore it\u2019s affecting coral reefs and seagrass beds and creating dead zones, which strips the oxygen out of the water,\u201d LaPointe said. \u201cThat\u2019s why we\u2019re getting these odors of hydrogen sulfide, which presents a human health risk.\u201d<\/p>\n
More aggressive seaweed removal efforts might be necessary, but these measures won\u2019t address the underlying causes of increasingly massive blooms in the ocean, LaPointe said. \u201cPeople are realizing this isn\u2019t going away. It\u2019s getting worse. It\u2019s the new normal. It\u2019s not only treating the symptoms but doing more research on the land-based nutrient sources that we can do something about,\u201d he said.<\/p>\n