The sargassum seaweed reached a new record in 2025, with 31 million metric tons floating in the Atlantic, according to the monitoring system SaWS from the University of South Florida. The figure exceeds by 40% the previous peak recorded in 2022, making it a potential environmental threat.
The phenomenon extends from the African coasts to the Gulf of Mexico, seriously affecting the Caribbean and Florida, according to satellite images released by NOAA and USF.
This marine macroalgae generates economic, environmental, and health impacts, damaging coastal biodiversity and affecting tourism, one of the main sources of income in the region.
Scientists warn that the growth of sargassum is due to multiple factors, such as climate change, excessive use of fertilizers, and nutrient runoff from rivers like the Amazon and the Mississippi.
Invaded Beaches, Health at Risk, and Tourism in Jeopardy
The East coast of Florida already reports large accumulations in areas like Miami Beach and Key Biscayne, while in Mexico, authorities have deployed barriers in Quintana Roo to halt its arrival.
In Barbados, Guadeloupe, and Dominica, the seaweed has already caused a drop in hotel reservations, according to local tourism associations.
As it decomposes, sargassum releases toxic gases like hydrogen sulfide, which can cause irritation, nausea, and respiratory problems. It also affects reefs and seagrass beds by blocking sunlight and reducing oxygen in the water, becoming an environmental threat.
The use of heavy machinery for its removal also causes collateral damage to coastal fauna and beach structures.
Research and Developing Solutions
Given the magnitude of the problem, potential industrial uses of sargassum are being explored, such as biofuels, construction materials, and water filters. However, its ability to absorb heavy metals poses health challenges.
Some pilot projects are analyzing controlled sinking of the seaweed to capture carbon, although environmental assessments are required to avoid adverse effects.
The sargassum peak is expected between June and August. The University of South Florida continues satellite monitoring and issues monthly alerts so governments and communities can prepare for its arrival.
Once again, the ocean shows the effects of an imbalanced system. Sargassum is not just a seasonal nuisance: it is a growing symptom of the global environmental crisis.
Sargassum seaweed. Photo: Ethics.
The Impact of Sargassum on Coasts: An Environmental Threat
The massive accumulation of sargassum on coasts represents a serious environmental problem. These floating algae, when they reach land, decompose rapidly, releasing gases like hydrogen sulfide, causing foul odors and affecting air quality.
In addition to the discomfort for residents and tourists, sargassum decomposition alters coastal ecosystems. It reduces oxygen in the water, blocks sunlight, and damages sensitive habitats like coral reefs and seagrass beds.
Economically, beaches covered with sargassum affect tourism activity, the main source of income in many regions of the Caribbean and Central America. Constant cleaning entails significant expenses for local governments and businesses.
The use of heavy machinery for removal also has negative impacts, as it can erode beaches and disturb coastal fauna. Faced with this, experts seek sustainable solutions to manage sargassum without further damaging the environment.
