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Record amount of seaweed is choking the Caribbean

by | Aug 17, 2022 | Science and Environment | 0 comments

Most years, tourists flock to beaches across the Caribbean for the golden sun and sand, but this year they are increasingly met with the “golden tide”. In 2018, record high amounts of seaweed were found on shores across much of the Caribbean including US territories such as Puerto Rico and the US Virgin Islands. This seaweed, a type of brown, gold algae called sargassum also known as “golden tide,” washed ashore in unprecedented quantities.   The seaweed quickly piled up on beaches and began to rot, attracting insects and repelling tourists. Throughout 2018, the golden tide resulted in many islands declaring a state of emergency as it hindered fishermen, had fatal consequences for turtles and dolphins and smothered seagrass meadows and coral reefs.

In normal years seaweed is viewed as more of a blessing than a curse. Ecosystems similar to the Sargasso Sea are formed as a result of seaweed accumulation which gives sanctuary to turtles, eels, and Sargassum fish. Although seaweed has ecological benefits this year many countries are facing states of emergency due to an excess of seaweed disrupting the ecosystem. 

In San Juan, Puerto Rico, this record amount of seaweed has smothered the coast causing a decrease in tourism and an increased release of toxic gas. Since Puerto Rico is located on the eastern side of the Caribbean, the islands face extreme exposure to seaweed. In high quantities, the seaweed has been known to strip the water of oxygen, killing fish and seagrasses that provide key habitats to many different aquatic species. It has also led to the smothering of coral reefs and a reduction in sunlight needed by ocean plants.

A variety of aquatic animals including crabs, dolphins, eels, and various species of fish usually benefit from the seaweed’s protection. However for humans, once washed ashore, the toxic gasses released from rotting seaweed can result in heart palpitations, shortness of breath, and dizziness, which can affect people already suffering from respiratory problems including asthma. With Puerto Ricans experiencing some of the highest rates of asthma among Americans, this seaweed outbreak will only serve to exacerbate the situation.

Similarly, in the US Virgin Islands, the Biden administration has been forced to declare a federal emergency after warnings of “unusually high amounts” of sargassum in desalination plants were reported. This emergency has put desalination plants like those near St. Croix in danger of being unable to meet high demand amidst a drought. According to Daryl Jaschen, director of the islands’ emergency management agency, “We’re consuming [water] as much as we can produce right now”.

Higher amounts of seaweed are also putting the US Virgin Islands electricity generating station in jeopardy as it relies on petrified water from desalination plants. These electricity stations give the government a green alternative to reduce emissions monitored by the US Environmental Protection Agency. However, without them, emissions will only increase which could produce a vicious cycle of high seaweed rates and a lack of pure water for the island.

According to a report published by the University of South Florida in 2022, the amount of seaweed across the Caribbean has increased from 18.8 million tons in May to 24 million tons of sargassum in June. July saw no decrease in seaweed causing experts like Chuanmin Hu, an optical oceanography professor who helps produce University of South Florida reports, to be extremely nervous. Dr.Hu noted that the levels of seaweed have increased by 20% from a previous 2018 record. 

Although many scientists note the importance of more research to better understand the root cause of increased sargassum levels in the region, the United Nations Caribbean Environment Program cites the rise in water temperatures as a result of climate change and nitrogen-laden fertilizers as the main culprit of the seaweed blooms. 

While hopes for seaweed-free beaches across the Caribbean next summer are high, Dr. Hu warns not to be too optimistic. With the impacts of climate change in the Caribbean worsening every year these kinds of massive sargassum blooms may become a “new normal” causing disruptions in ecosystems and economies. It appears that tourists may now have to become accustomed to “the golden tide” on their golden Caribbean beaches. 



Isabella Efimov

Isabella Efimov

Isabella Efimov is a junior at Imagine International Academy of North Texas in Dallas. She is passionate about advocacy in the environmental justice space and politics. She has interned at Their Stories and founded her own nonprofit, The Water Inequity Network. Isabella enjoys volunteering for local political campaigns as well as other local non-profits pertaining to climate change. She enjoys figure skating with her team, reading, and spending time with friends. Isabella is a former Science & Environmental Affairs Intern Correspondent at Pasquines.


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