Mysterious Sargassum seaweed outbreaks threaten tourism, marine life in Gulf and Caribbean


The lives of sea turtles and other marine life were placed at risk when a mass Sargassum, a brown seaweed, inundation event occurred in Barbados on the morning of Monday, June 4.

While multiple sea turtles were rescued, there were a number of sea turtles and baby dolphins found dead, according to the Barbados Sea Turtle Project.

A similar event took place in Barbados in 2015. The event led to the deaths of over 40 turtles and hundreds of fish, eels and crabs.

sargassum sea turtles

Loggerhead sea turtle hatchlings are shown at the Gumbo Limbo Nature Center before being taken to a U.S. Coast Guard vessel for release, Monday, July 27, 2015, in Boca Raton, Fla. More than 600 sea turtle were released onto free-floating sargassum seaweed offshore. 
Heavy layers of smelly, thick brown seaweed could potentially wreak havoc along the shorelines of your favorite vacation spots.

After escaping from the Sargasso Sea, this menacing seaweed has been devouring beaches along the Gulf of Mexico and the Caribbean.

The Sargasso Sea is a region in the North Atlantic Ocean near the Bermuda Triangle. It is bounded by four currents forming an ocean gyre. The region is known for its high concentration of floating Sargassum.

It is the only sea that is not surrounded by a land boundary, according to the National Oceanic and Atmospheric Administration (NOAA).

Christopher Columbus is credited with the first written account when he encountered Sargassum in the Sargasso Sea in 1492. It was his sailors who created the early myths and legends, according to the Sargasso Sea Alliance.

Sargassum is a set of brown algae species that float on the ocean surface in the North Atlantic Ocean, according to Dr. Straun R. Smith, curator at the Natural History Museum, Bermuda Aquarium, Museum and Zoo.

These plants have recently been found in equatorial waters between west Africa and northeastern South America.

While recordings show that mass influxes of Sargassum have cursed shorelines for decades, researchers say the algae blooms have exploded in extent and frequency in recent years, according to the Associated Press.

There is a limited amount of information available about Sargassum habitats because it is very difficult to sample. There is a need for further research into the history of mass Sargassum strandings in the Caribbean to better understand the trends and patterns of this seaweed.

The drivers of Sargassum are not fully understood, but some potential influences include ocean currents, ocean temperatures, rainfall patterns, hurricanes and nutrient levels, according to Smith.

Sargassum seaweed

Large quantities of seaweed blanket the beach in the east coast “Playa Los Machos” in Ceiba, Puerto Rico, Saturday, Aug. 8, 2015. 
In recent years, there have been a number of mass Sargassum events in the Caribbean and beaches in the United States.

Large quantities of seaweed blanketed beaches in Ceiba, Puerto Rico, in August 2015. The invasion included a number of shorelines so severely hit that some tourists canceled trips and lawmakers on Tobago called it a “natural disaster,” according to the Associated Press.

Beaches in Galveston, Texas, were inundated by massive piles of seaweed in the summer of 2014. The event drove away beach tourists and hurt the local economy, according to the Houston Chronicle.

Galveston locals dubbed it the “Summer of Seaweed,” where a rotten and pungent aroma stretched for miles down the Texas coastline, as layers of Sargassum laid rotting along the coast.

In January 2018, scientists gathered in Galveston to tackle the mystery of the mass inundation of seaweed.

Scientists continue to struggle to gain conclusive answers as to why this phenomenon happened and why it hasn’t recurred, according to the Houston Chronicle.


Seaweed accumulates on the beach, Tuesday, June 24, 2014, in Port Aransas, Texas. Front loading trucks and dump trucks have been used to help remove the Sargassum that keeps washing ashore. 
“Large quantities of Sargassum that strand on beaches are a nuisance for tourists and hotel operators because of the smell and the discoloration of the shallow waters on the beach (turns yellowy-brown), but this is not a health threat,” Smith said.

Sargassum becomes a problem and a challenge to remove when it gets piled up to about 1 to 2 feet.

“In Bermuda, we use beach tractors that drag large rakes behind them, to aggregate the Sargassum and then we bury it at the back of the beach. This gets done early in the morning before the tourists are active,” Smith said.

Sargassum composts very well. It is used as a traditional fertilizer in some places, such as Bermuda, once the salt has been leached out by rain water, according to Smith.

sargassum texas 2014

Chad Cox uses a rake to clear a path from the seaweed on the beach, Tuesday, June 24, 2014, in Port Aransas, Texas. Front loading trucks and dump trucks have been used to help remove the Sargassum that keeps washing ashore. 
While mass amounts of seaweed are a nuisance for tourists and beachgoers, the seaweed has numerous environmental benefits.

Sargassum is a critical habitat for many species, from nearly 150 species that are found only attached to or living with the floating clumps or who spend time living and feeding within Sargassum,” Smith said.

When the seaweed strands on beaches, the incorporation of the dead Sargassum on the beach sands helps to stabilize the beaches, reducing erosion by storm waves, according to Smith.

While Sargassum provides habitat for marine life, mass amounts can cause potential harm.

The decay of large quantities of Sargassum in enclosed bays can reduce oxygen levels temporarily. This can stress or kill attached animals, such as corals, seagrass, sponges and fishes, according to Smith.

Texas A&M Galveston has largely led the way in forecasting Sargassuminvasions through the development of Sargassum Early Warning System(SEAS). The satellite tracks Sargassum in the Gulf of Mexico. The system can give certain locations, such as Galveston, up to two weeks’ notice where there is no cloud cover.

However, scientists still want more information on the seaweed’s taxonomy, carbon emissions and long-term migratory patterns.

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