Visible from space, an explosion of floating sargassum masses is wreaking havoc on shorelines all the way from the West Coast of Africa to Florida, invading the Caribbean beaches of Mexico, the Dominican Republic, and other countries in the region.
Year after year, scientists monitoring sargassum reproduction in the Atlantic Ocean warn that “this season’s bloom will likely be the largest ever recorded,” and they never disappoint. This is now the “new normal,” they say.
Sargassum was first reported by Christopher Columbus 5 centuries ago when he wrote about his concerns regarding his caravels getting trapped in a sea of ocean plants.
This seaweed used to be harmless to humans, marine life and tourism economies until 2011, when it started to massively arrive on Caribbean beaches in what is now called “inundation events.”
Scientists from prestigious American and Caribbean universities have joined sources to try to understand what may be causing this phenomenon and what can be done to stop it.
The study, “Changes in holopelagic sargassum spp. biomass composition across an unusual year,” published in PNAS helps us understand the issue.
“Understanding sargassum’s response to environmental conditions is crucial for unlocking its biology and potential value,” said the lead author of the study, Dr. Thierry Tonon at the University of York.
What Is Causing So Much Sargassum?
Data gathered since 2011 has revealed the likely causes of these abnormal invasion events: overnutrified waters, warming temperatures, Saharan dust clouds and disturbances in liquid boundaries seem to be the main causes.
Scientists agree that there’s much more to learn about what’s causing this phenomenon.
Overnutrified Waters
Also known as a “human nitrogen footprint,” industrial-scale agricultural activities like intensive soya farming in the Congo and large amounts of nitrogen and phosphorus fertilizers deposited into the Amazon and Mississippi rivers by Brazil and the United States are fueling sargassum over-reproduction.
It’s worth noting that the use of agricultural fertilizers in Brazil soared since 2011.
Experts from multiple fields agree that this may be the main cause of all this mess.
Warming Temperatures
Climate change is reportedly increasing nutrients in deep ocean waters in the sargassum belt in West Africa. So, as a tropical plant, warmer waters also favor the over-reproduction of seaweed.
Saharan Dust Clouds
These “clouds” extend for thousands of miles across the Atlantic Ocean, fertilizing plankton and sargassum mats with nitrogen, iron and phosphorus. Saharan dust clouds are believed to be the main cause of the sargussum spike in 2015 and 2018.
Disturbance in Liquid Boundaries
An increase in strong winds, tropical storms, and spiraling currents is pushing sargassum to the Caribbean coasts.
Is there a Solution?
Entrepreneurs across the globe have been actively proposing innovative ideas to take commercial advantage of sargassum.
However, experts believe that while this biomass is abundant, its possible uses are limited due to its high arsenic content and other dangerous components.
“It is very important for Caribbean Islands being affected by the sargassum inundation to be able to benefit from its valorization. Understanding how the sargassum we collect in Jamaica has changed en route to our shores and factors that could affect it, especially the arsenic content, will propel us towards safe use of the algal biomass,” said Professor Mona Webber from the University of the West Indies.