Latest on sargassum seaweed in Costa Rica 2022

A new wave of sargassum has reached the beaches of the Costa Rica Caribbean. It is a seaweed that, when decomposing, produces hydrogen sulfide, which can irritate the eyes and respiratory tract and, in large concentrations, can be toxic. In large concentrations, it can be toxic.

Latest on sargassum seaweed in Costa Rica 2022
Sargassum generated the greatest impact on Parquecito beach, in the center of Puerto Viejo, Costa Rica. Image: Courtesy

Once again, sargassum arrives at the beaches of the Costa Rica Caribbean. According to the Natural Resources and Wildlife Laboratory of the School of Biological Sciences of the National University, since last Friday, April 15, they have been monitoring a new wave of this natural phenomenon.

The first observation took place on April 15 at Agua Buena beach in Barra del Colorado, on the border with Nicaragua, with a moderate to low level of entry. On Monday 18 it began to be observed in Negra beach, Puerto Viejo and Punta Uva in low quantities; however, as of 19, the number of algae began to increase significantly, a condition that is maintained.

Considerable volumes or spots are also observed on the surface of the sea, which is expected to enter in the next few days. This may be occurring due to the rainy weather conditions in the country. Sargassum is a brown seaweed that floats in the ocean and due to the strong winds in the North Atlantic, it moves to the coasts of Mexico, Colombia, and Costa Rica.

Sargassum has arrived on the southern Caribbean coasts before but in smaller volumes. There have been more winds in this area that drag the seaweed, which when it loses its pneumatocysts (structures that allow the organism to float) it dies and goes to the bottom of the sea.

It can settle on seagrasses, corals, and in general in all ecosystems. The decomposition of this biological material produces hydrogen sulfide -similar to that generated in sewers and which produces a hard-boiled egg smell- which can irritate the eyes and respiratory tract and in large concentrations can be toxic to marine life and even humans.

Volunteers work to remove seaweed from Costa Rica's Caribbean beaches. (UNA)
Volunteers work to remove seaweed from Costa Rica's Caribbean beaches. (UNA)

Different institutions in the country are working to face the challenges posed by the appearance of sargassum in the country's Caribbean. To this end, the first inter-institutional and inter-sectoral meeting was held on March 15 to define a road map to provide a solution to this and future sargassum arrivals.

Coordination with other organizations will allow the exchange of experiences, development of action protocols for prevention, detection, management of the impact on tourism, coastal marine ecosystems, public health and safety, fishermen, in addition to monitoring events, research, studies of possible uses and exploitation of sargassum.

The phenomenon may affect economic activities such as fishing and tourism in Limón. Fishermen, hoteliers, and tour operators have reported inconveniences and fear a rebound in the affectation due to the presence of these algae stains on the high seas and beaches.