Toxic gas, livelihoods under threat and power outages: how a seaweed causes chaos in Caribbean

Schools evacuated due to toxic gas. Smelly tap water at home. Tourist operators and fishers struggling to stay in business. Job losses. Power outages affecting tens of thousands of people at a time. Dangerous health problems. Even lives lost.

Such crises were some of the consequences of sargassum seaweed in the islands of the Caribbean in 2023, which have become common in the region since 2011, when massive blooms began inundating the shorelines in the spring and summer months.

On 18 April 2023 in Guadeloupe, the air-quality monitoring agency Gwad’Air advised vulnerable people to leave some areas because of toxic levels of gas produced by sargassum. Six weeks later, about 600 miles to the north-west, it blocked an intake pipe at an electricity plant at Punta Catalina in the Dominican Republic. One of the facility’s units was forced to temporarily shut down, and a 20-year-old diver named Elías Poling later drowned while trying to fix the problem.

In Jamaica, during the months of July and August, fishers found themselves struggling through another season as floating sargassum blocked their small boats and diminished their catch.

“Sometimes, the boats can’t even come into the creek,” said Richard Osbourne, a Jamaican fisher. “It blocks the whole channel.”

In the British Virgin Islands (BVI), most of Virgin Gorda’s 4,000 residents had to deal with sporadic water shut-offs and odorous tap water for weeks after sargassum was sucked into their main desalination plant last August.

And in Puerto Rico, a highly unusual late-season influx inundated the beaches of the Aguadilla area for the first time, leaving residents such as Christian Natal out of work for a week when it shut down businesses, including the jetski rental company where he works.