In May and June 2026, the University of South Florida (USF) and NOAA confirmed that the biomass of sargassum measured by satellite reached historic levels, surpassing all records since systematic monitoring began.
The so-called Great Atlantic Sargassum Belt, which stretches from Africa to America, has covered extensive areas of the Caribbean, the Gulf of Mexico, and Florida, affecting tourism, fishing, and coastal communities.
The Sargassum Watch system estimated that in May, more than 40 million metric tons were floating, covering 4% of the regional ocean surface.
Factors Explaining the Record
According to USF and NOAA, the phenomenon is due to a combination of:
- Increase in sea surface temperature.
- Excess nutrients discharged by the Amazon River.
- Favorable currents and winds that intensify proliferation.
- Climate change and human activity, which increase the discharge of fertilizers and organic matter.
Environmental and Health Impacts
Sargassum plays an ecological role in the open sea, serving as a refuge for fish, turtles, and birds. However, on the coasts it causes problems:
- Release of hydrogen sulfide, an irritating gas with a rotten egg smell, affecting people with asthma or respiratory diseases.
- Concentration of heavy metals and microplastics, posing additional risks to health and the environment.
- Disruption of the natural balance and loss of recreational access to beaches.
Economic Consequences
- In Mexico, SEMAR collected more than 91,000 tons in 2025, and in 2026 arrivals began earlier and with greater intensity. The annual cleaning cost exceeds 150 million pesos.
- In Florida, counties like Miami-Dade and Broward deploy daily cleaning operations and issue warnings to tourists.
- Hotels and tour operators report cancellations and a reduction in visitors, affecting local economies dependent on tourism and artisanal fishing.
Most Affected Areas in 2026
- East coast of Florida.
- Yucatan Peninsula (Quintana Roo), with a red alert on 28 monitored beaches.
- Caribbean Islands: Jamaica, Dominican Republic, Barbados, and Guadeloupe.
Responses and Alternatives
The governments of the United States, Mexico, and the Caribbean have implemented:
- Satellite monitoring and weekly reports from NOAA and USF.
- Sargassum vessels and cleaning brigades in Mexico.
- Health recommendations to avoid direct contact and limit exposure.
- Exploration of alternative uses: biofuels, fertilizers, and construction materials, although under strict controls due to contaminants.
The summer of 2026 could become the period of greatest sargassum accumulation since records began. The situation demands international cooperation, continuous monitoring, and the development of technologies for early detection and offshore collection.
The phenomenon, linked to climate change and human activity, has become a permanent environmental reality for the Atlantic and the Caribbean.
