Caribbean Hit Hard by Sargassum Seaweed Invasion

When scientists speak of the Sargasso Sea, which occupies part of the Atlantic Ocean, there is usually little mention of things drifting out because of the immobile currents.
That is until now. Over the past few weeks, seaweed from the Sargasso Sea has been making its way towards the Caribbean, washing up en masse on beaches as surrounding currents change with weather and temperature patterns.

It's a situation that is posing serious problems for local ecosystems and critical industries such as tourism and fishing.

"It's the first time in history that I or anyone in the fishermen association have seen so much sargassum weed invading our shores," Gerald Price, communications officer for the Antigua and Barbuda Fishermen Association, told IPS. He said the seaweed was clogging the engines of most of the boats used by the fishermen.

While it the cause remains unclear, the Antigua Fisheries Division notes that "strong and unusual currents from recent storms have probably brought the mass of seaweed from the Sargasso Sea to the Caribbean.

Changing currents and more powerful storms due to climate change are one possibility. Another is rising ocean temperatures, and the resulting effects on the growth rates of different marine species. Vince Best, an environmental scientist and lecturer at Antigua State College, told IPS, "It is possible that climate change could be indirectly responsible for the proliferation of this particular weed which is currently affecting many global coastlines.

"Increased temperatures and the associated effects may be the precursor which is somehow affecting the overall physiology of the various species of this weed causing, maybe, excessive growth; hence the excessive amounts of the weed seen in aquatic environments"

The species being observed is a brown, macro-algae called Sargussum fluitans (sargassum seaweed), free-floating algae found on the open sea surface and known to occur in this region. It is often found in association with Sargasso weed (Sargassum natans) that is native to the Caribbean.

"It's hard to tell the real reason why the sargassum weed is washing up on shores in the Caribbean without some kind of technical assessment," Sandra Prescod Dalrymple, environmental resource management specialist with ESP Consultants (Caribbean) Inc. told IPS.