Written by Nereus Research Associate Ryan Swanson,

Nereus research associate Colette Wabnitz (UBC) recently appeared in a Reuters article about the toxicity resulting from Sargassum (seaweed) decomposition throughout the Caribbean. In the piece, tourists are cautioned about potential health effects from visiting beaches where Sargassum has accumulated and decomposes, because it releases hydrogen sulfide gas and ammonia that can cause “heart palpitations, shortness of breath, dizziness, vertigo, headache and skin rashes”. But even with these potential health risks, the article is careful to point out that they are not serious enough for travelers to cancel or change their plans. Additionally, they write that resorts take regular measures to clean up affected beaches that tourists frequent by hiring clean-up crews and sending out boats to remove beds of seaweed close to shore. Colette confirms this by stating “While mass blooms have been forecast for this year, they are less expansive than last year, and I would not cancel my holidays” adding that “there is no need to panic, [and] use common sense and make sure to heed local travel and health advisories.”

Colette co-wrote a blog about the Sargassum mass-bloom of 2018 for the Nereus Program, in which she and co-authors wrote that while blooms have occurred in the past, 2018 was especially bad for the amount of Sargassum that accumulated on shores throughout the Caribbean. They wrote that it  “[piled] high up on beaches, shading seagrass beds from the sunlight they need to thrive, entangling sea turtles, and [decayed] in shallow water or on beaches filling the air with a stench of rotten eggs.” This was the case on beaches in Florida, Mexico, Belize, Barbados, Cuba, the Cayman Islands, and throughout the Lesser Antilles and French Guyana. They further discussed the origins of these Sargassum blooms, how they’re triggered, and what can be done about them. Colette’s blog was also referenced in the Riviera Maya News, in which the head of tourism for the Mexican state of Quintana Roo clarified that not all of its beaches contained Sargassum build-ups, as was being reported on throughout the Caribbean in 2018.