Huge masses of foul-smelling seaweed in the Caribbean could cause headaches for sun-seekers
CBC
Every winter, millions of Canadians head down to the Caribbean in search of sunshine, pristine beaches and crystal-clear waters.
This year, however, tourists may have noticed something not-so-pleasant awaiting them on the beach: stinky, brown sargassum.
Over the past decade, the foul-smelling seaweed has become more common on beaches around the Caribbean and the south Atlantic Ocean. So what's going on? To understand, first you need to understand sargassum.
Sargassum is a type of brown seaweed (and a form of algae) found in the Atlantic Ocean. It is made up of leafy pieces, as well as oxygen-filled, round berry-like bits that help it float on the surface. It doesn't have any roots or seeds.
Unlike some other types of seaweed, it lives its entire life on the surface of the ocean in small patches. Sargassum is usually found in a region called the Sargasso Sea, where it tends to circulate in a vortex called a gyre, through a five-million square kilometre belt that runs from Chesapeake Bay in the mid-Atlantic, all the way to the Caribbean.
However, sargassum can clump together, creating rafts or or patches. It has a seasonal cycle, beginning in the spring, reaching its peak in the summer, and finally dying off in the fall.
Sometimes large collections can wash up on beaches, which can be an annoyance to beach-goers. But they're vital to some marine life, providing food and breeding grounds for animals such as fish, sea turtles and more.
"[Sargassum] has formed these enormous floating masses in the open sea, which are wonderful, actually … because they soak up carbon, they suck up nutrients, they sustain a lot of life, and a lot of animals depend on them," said Brigitta Ine van Tussenbroek, a scientist at the National Autonomous University of Mexico's Institute of Marine Sciences and Limnology.
"Even the American eel, the Northern European eel, they wouldn't exist without the Sargasso Sea, for example. So it's a wonderful system."
While most sargassum usually remains in this gyre, it can travel along a sort of conveyor belt in the Atlantic and Caribbean. Scientists have seen a noticeable increase in sargassum washing up on beaches in the Caribbean since 2011.
"Sometimes, some of these gyres … slackened, and some of the sargassum escaped and then went to Cuba, to Hispaniola, and some ended up in Mexico pass to the Gulf of Mexico. And then it went back to the Sargasso Sea," van Tussenbroek said.
"Since 2010–11, suddenly, some sargassum started to accumulate in a new area, which is just north of the equator in the tropical Atlantic."
Why is this happening? Scientists aren't sure.
A number of factors could be at play, including climate change and human activity, said van Tussenbroek.
