What seems to be a strange phenomenon is occurring along our east coast beaches. A massive tide of pelagic sargassum, or seaweed as it is commonly called is inundating our coastlines and washing on to the shores of the popular sea turtle nesting beaches. A similar event occurred in the Caribbean in 2011.
Pelagic sargassum is a brown invasive alga, or seaweed which reproduces vegetatively and floats free in the ocean and never attaches to the ocean floor. These free-floating forms are only found in the Atlantic Ocean. There are two species involved in the sargassum influx: sargassum natans and sargassum fluitans.
This excessive seaweed is hindering turtle-nesting activities on Matura Beach, Fishing Pond, Manzanilla and Mayaro beaches. Community groups involved in the National Sea Turtle Conservation Programme along the east coast suggest that this is the worst it has ever been. However, contingency plans are currently being put in place.
Manual and volunteer labour is currently being used to clear the shorelines. As such, turtles are still able to nest successfully. This problem is only on the east coast beaches, and as far as we are aware it is not affecting the north coast.
In embracing the challenge of sargassum, good communication among agencies, the press, and with locals and visitors are essential. Here's what you need to know about sargassum in the Caribbean.
Where does it come from? The algae originate in the Sargasso Sea in the Atlantic Ocean around Bermuda.
It is believed that the recent influxes are related to massive sargassum blooms occurring in particular areas of the Atlantic, not directly associated with the Sargasso Sea, where nutrients are available and temperatures are high. The sargassum consolidate into large mats and are transported by the Gulf Stream.
The sargassum do not necessarily affect the same location all year. It is transported on currents and progressively affect different locations across the region. At any one time of the year there are multiple locations that can be affected.
Are there ecological benefits? Sargassum normally occur naturally on beaches, albeit in smaller quantities.
Although sargassum pose a risk to sea-turtle nesting and later in the year to the hatchlings; and it is normally seen as a nuisance for local residents and travellers, it does offer some ecological benefits. It plays a role in beach nourishment and is an important element of shoreline stability.
Sand dune plants need nutrients from the sargassum and sea birds, for example, depend on the sea life carried in the sargassum for food. Sargassum also provide refuge for migratory species and essential habitat for some 120 species of fish and more than 120 species of invertebrates. It is an important nursery habitat that provides shelter and food for endangered species such as sea turtles and for commercially important species of fish such as tuna.
Are there any human health concerns associated with sargassum? During decomposition there will inevitably be a smell and insects around. This process is not toxic to humans. Reports suggest that persons were being "stung" by the seaweed. Sargassum do not sting. Depending on the type of sargassum you encounter, you might feel the pointy ends of the buoyancy pods of Sargassum natans.
When it decomposes on sand you might notice a black layer underneath, but this is normal and a sign of Mother Nature doing her work of incorporating the sargassum into the beach.
Some scientists associate the cause of sargassum with higher than normal temperatures and low winds, both of which influence ocean currents, and they draw links to global climate change. We do not know for sure if sargassum influx will happen every year, but from the signs from the Eastern Caribbean so far this year, we'll be seeing sargassum in the region periodically throughout 2015.
