SAN JUAN, Puerto Rico (AP) – Near-record amounts of algae are choking the Caribbean coast from Puerto Rico to Barbados, killing fish and other wildlife, stifling tourism and releasing foul-smelling, noxious gases.
More than 24 million tons of sargassum covered the Atlantic in June, beating the all-time record set in 2018 by 20 percent, according to the University of South Florida Optical Oceanography Laboratory.  And unusually large amounts of the brown algae have washed up in the Caribbean Sea.
A tangled carpet of vegetation recently surrounded an uninhabited island near the French Caribbean territory of St.  Martin that is popular with tourists, forcing officials to suspend ferry service and cancel kayaking, paddling and snorkeling tours.  The normally translucent blue-green waters around Pinel Island turned into a dark-brown mud.
Oswen Corbel, owner of Caribbean Paddling, said he had to close his business in St.  Martin on July 22 and doesn’t expect to reopen until late October.  It was estimated that he has lost at least $10,000.
“Maybe I should give up.  … Sometimes I think I should go to the mountains and herd sheep, but that’s what I know how to do,” he said.  “What’s next? We’ve had Hurricane Irma, we’ve had COVID, we’ve had sargassum, and now I’m pretty scared of global warming.”
Scientists say more research is needed to determine why sargassum levels in the region are so high, but the United Nations Caribbean Environment Program said possible factors include rising water temperatures as a result of climate change and fertilizers and waste water containing nitrogen.  they feed on algae.
“This year has been the worst year on record,” said Lisa Krimsky, a university researcher with Florida Sea Grant, a program that aims to protect the coast.  “It’s absolutely devastating for the region.”
He said large masses of algae have serious environmental impacts, with decaying algae altering water temperatures and pH balance and leading to declines in sea grass, corals and sponges.
“They’re basically drowning,” Krimsky said.
The “gold tide” has also hit people hard.
The concentration of algae is so great in parts of the eastern Caribbean that the French island of Guadeloupe issued a health warning in late July.  He warned some communities of high levels of hydrogen sulfide gas coming from the huge rotting kelp clumps.  The gas, which smells like rotten eggs, can affect people with breathing problems such as asthma.
The Biden administration declared a federal emergency after the US Virgin Islands warned last month of unusually high amounts of sargassum clogging machinery at a desalination plant near St.  Croix struggling to produce water and meet demand amid drought.
In addition, the US Virgin Islands power station relies on ultra-pure water from the desalination plant to reduce emissions.  The loss of such water would force the government to use a type of diesel fuel that is more expensive and in limited supply, officials said.
Chuanmin Hu, an oceanography professor at the University of South Florida who helps produce the algae reports, said sargassum levels for the eastern Caribbean were at a near-record high this year, second only to those reported in July 2018. Levels in the northern Caribbean are at their third highest, he said.
Experts first noticed large quantities of sargassum in the Caribbean Sea in 2011, and the problem has occurred almost every year since then.
“We don’t know if this is a new normal,” Krimsky lamented.
Sargassum in moderation helps clean water and absorb carbon dioxide and is an essential part of the habitat for fish, turtles, shrimp, crabs and other creatures.  It is also used in fertilizers, food, biofuels, construction materials and pharmaceuticals.
But it is bad for tourism and the environment when too much accumulates just offshore or on beaches.
“This is the worst we’ve ever seen for sure,” said Melody Rouveure, general manager of a tourism company in the Dutch territory of St.  Maarten in the Caribbean, which shares an island with St.  Martin.  “Ruined my personal beach plans.”
On Union Island, which is part of St. Vincent and the Grenadines, the algae invasion has forced some resorts in recent years to close for up to five months.
Masses of sargassum have also strangled the Caribbean fishing industry.  It destroys boat engines and fishing gear, prevents fishermen from reaching their boats and fishing grounds, and leads to a reduction in the number of fish caught.  Barbados, where the beaches are full of brown-red algae, has been particularly hard hit.
An overabundance of sargassum has been blamed for the recent deaths of thousands of fish on the French Caribbean island of Martinique.  It also has activists concerned about the plight of endangered turtles.  Some die at sea, entangled in the seaweed or unable to lay their eggs because of the carpet of seaweed over the sand.
In the Cayman Islands, officials began a test program in which crews pumped more than 2,880 square feet (268 square meters) of algae from the water.  But on Tuesday, the government announced it was suspending the project, saying the algae had decayed so much that it had rendered pumping useless.
Some island nations use heavy machinery to remove the seaweed from the beach, but scientists warn it causes erosion and can destroy the nests of endangered turtles.
Many Caribbean islands are struggling financially and do not have the means to clean up the huge amounts of seaweed.
Governor Albert Bryan of the US Virgin Islands said he asked President Joe Biden to declare a state of emergency for the entire tri-island territory, not just St. Croix, but that did not happen.  Brian said he’s now trying to find local resources to clean up the beaches, “but a lot of things need money right now.”