A new study has revealed that massive blooms of sargassum seaweed are costing some U.S. coastal communities millions, and even up to a billion dollars, in economic damage each year. The affected regions include Florida, Puerto Rico, and the U.S. Virgin Islands.
The sargassum blooms, which peak during the summer months, originate in the Atlantic Ocean and float on the water’s surface, providing a habitat for marine life. However, these massive amounts of seaweed also carry ocean plastic and pose several health risks for humans and animals. The blooms can even force the closure of beaches for months, hurting local tourism.
Tracey Dalton, a professor of marine affairs at the University of Rhode Island, stated that while the ecological and public health impacts of sargassum inundation events have been widely documented, “their direct and indirect economic costs to governments, coastal communities and private industries had not previously been quantified.”
The researchers used economic modeling, satellite observation, and data on hotel cancellations, visitor spending, and declines in commercial and recreational fishing to assess the financial toll of the sargassum blooms. They found that the sargassum seasons, typically lasting from March through October, are starting earlier and lasting longer in the western Atlantic and the Caribbean.
Southeast Florida, Puerto Rico, and the U.S. Virgin Islands face the highest risk of severe sargassum inundation. The researchers noted that existing sargassum forecasting tools are performing well, but stressed the “urgency of sustained investment in sargassum monitoring, forecasting and cleanup infrastructure.”
Beyond the financial impact, the sargassum blooms also pose health concerns. The decaying seaweed releases hydrogen sulfide gas, which can irritate the eyes, nose, and throat, sometimes leading to breathing difficulties. Exposure to the toxins and heavy metals released by the blooms can also be harmful to both humans and animals.
While the causes of the unprecedented sargassum events are not entirely clear, the study authors say they are a symptom of broader shifts in the Atlantic Ocean. As the climate continues to change, these large-scale environmental drivers are directly connecting to coastal economic vulnerability.
