The Caribbean Has A Big Seaweed Problem - And It's Costing Millions

To learn more about the sargassum phenomenon, join the Virtual Island Summit!

As part of a natural biological cycle, seaweed has grown in small amounts in the Atlantic before being carried by currents into the Gulf of Mexico for thousands of years. However, since 2011, inhabitants of the region from Florida to Mexico and as far south as Brazil have noticed an increase in the amount of macro-algae washing up on their beaches. In early July, a 550 kilometer-long mass of sargassum seaweed slowly made its way through the Caribbean, draping the shores in a thick coat of algae.

Sargassum blooms in such large amounts are a relatively new problem impacting countries including Guyana, Mexico, Barbados, Saint Lucia, Jamaica, Guadeloupe, and Belize.

The phenomenon is one of many being discussed at the upcoming Virtual Island Summit, an online conference bringing together islands from around the world to collaborate on sustainable development. Usually, sargassum would accumulate on shore for two or three weeks a year in small clumps, but as Mexico National University’s Rosa Rodríguez-Martínez, illustrates: “We are getting sargassum almost from March to October. So basically, more than half of the year we are receiving massive amounts. It’s impressive. It's a problem. Economical problem, ecological, and probably a human health problem also.”

The Butterfly Effect

Scientists began to notice a pattern in sargassum growth in 2011, when satellite data picked up an algal-bloom in Brazil at the mouth of the Amazon river, much farther south than where sargassum usually grows. Researcher Chuanmin Hu of the University of South Florida College of Marine Science explains: “Because of global climate change we may have increased upwelling, increased air deposition, or increased nutrient source from rivers, so all three may have increased the recent large amounts of sargassum.”

Continued research showed that a mixture of fertilizer run-off flowing from the Amazon and a nutrient-rich upwelling from the West-African coast created the ideal conditions for a bloom. Two major algal blooms have been recorded since 2011, in 2015 and 2018. Each has been larger than the last, 2018’s sargassum event was estimated to weigh upwards of 22 million tons and stretches between the Caribbean and African coasts.

Sargassum growth 2011-2018.

While sargassum plays an important role in marine ecology and the development stages of many animals, it can have a detrimental effect when too much is present. Trapping sea-life and choking coral reefs before decomposing on beaches and releasing toxins, the algae is becoming a major environmental issue and is the sign of further-reaching environmental issues.

Environmental Economics

Tons of seaweed are washing up daily, leaving some nations to declare a national emergency to deal with the problem. The smell of rotten eggs caused by decaying sargassum has become an issue for the tourism sector, but the sheer amount of algae needing to be cleared by local authorities is staggering, as the mayor of Cancun, Mara Lezama, describes: “Fighting sargassum is a chore every day. You clean the beaches in the morning, and sometimes you clean them again in the afternoon or at night, and then you have to go back and clean it again.”

The cost of collecting and disposing of the rotting mass of algae off of Caribbean beaches peaked at US$120 million in 2018, and that number could rise considering the increasing amount of seaweed growing in the Atlantic. However, the tourism industry is not the only one affected by the large amounts of sargassum choking the environment. Fisheries from Florida to Mexico are concerned that the continued proliferation of algae in the Gulf will lead to a drop in fish stocks, potentially dealing a massive blow to the industry.

From floating nets to additional manpower on the beaches, governments have invested in different management techniques to manage the influx, but some are seeing the arrival of sargassum as an opportunity. Some companies have explored using the seaweed as organic fertilizer, a bio-fuel as well as in cosmetics. Algas Organics, a Saint Lucian company, has created a sargassum seaweed-based fertilizer that began retailing in 2015. Meanwhile, scientists are still unsure as to how this massive algal bloom will develop, creating more uncertainty surrounding any potential solutions, but governments are expecting algal-blooms to be as frequent as hurricanes - the new normal. Innovation is needed to find a solution that will reduce the impact of the blooms and find a way to make use of the large amounts of seaweed washing up on the beaches. Islands are some of the first to be affected by climate change and have been leading the charge in low-carbon innovation and renewable technologies and now sargassum is yet another pressing challenge for which the Caribbean must find a solution.

To learn more about the sargassum phenomenon, join the Virtual Island Summit panel sponsored by Enexor Bioenergy.