Combatting a seaweed assault in the Caribbean

The Caribbean is usually associated with crystal clear waters and white sandy beaches. But in recent years, tons of stinking brown seaweed have been invading the coastline, spoiling tourist hotspots like Cancun and Tulum in Mexico.

The seaweed, known as sargassum, is more commonly found in the much colder Sargasso Sea, part of the Atlantic Ocean bound by four major currents some 1,000 kilometers (621 miles) northeast of the Caribbean. But the seaweed is growing rapidly in its new home, thanks to the warmer waters there — a situation worsened by climate change. The seaweed also has plenty to feed on as the Caribbean waters are relatively nutrient-rich because of a high incidence of fertilizer runoff.

Not only is the seaweed problem affecting tourism, it's also changing the marine ecosystem and stifling biodiversity, as the algae sucks up so much oxygen. And for now, it appears the situation is unlikely to change. On the contrary, this year Barbados called a national emergency because of the seaweed assault.

In Mexico though, some are looking for solutions that range from a barrier in the sea to using the seaweed for biogas and as a building material. But will it all be enough to halt the seaweed scourge?

A film by Katja Döhne