San Juan, Puerto Rico — Record amounts of seaweed are choking Caribbean shores from Puerto Rico to Barbados as tons of brown seaweed kill wildlife, choke the tourism industry and release toxic gases.

More than 24 million tons of sargassum blanketed the Atlantic in June, up from 18.8 million tons in May, according to a monthly report from the University of South Florida’s Optical Oceanography Laboratory that notes “a new historic record.

July saw no decrease in algae in the Caribbean Sea, said Chuanmin Hu, an optical oceanography professor who helps produce the reports.

“I was scared,” he recalls feeling when he saw the historic June figure. He noted that it was 20% higher than the previous record set in May 2018.

Hu compiled additional data for The Associated Press that showed sargassum levels for the eastern Caribbean hit a near-record high this year, just after those reported in July 2018. Levels in the northern Caribbean are at an all-time high. third-highest level, after July 2018 and July 2021. , he said.

Scientists say more research is needed to determine why Sargassum levels in the region are rising to new highs, but the UN Caribbean Environment Program says possible factors include rising water temperatures due to climate change and nitrogen laden fertilizers and sewage fueling algal blooms.

“This year has been the worst year on record,” said Lisa Krimsky, Florida Sea Grant researcher and faculty member and regional water resources officer at the University of Florida. “It’s absolutely devastating for the region.”

She said large masses of algae have a serious environmental impact, with the decomposition of algae altering water temperature and pH balance, as well as declining populations of seagrass, coral reefs and fish. sponges.

“They’re basically muffled,” Krimsky said.

The “golden tide” has also hit humans hard.

The concentration of algae is so high in parts of the eastern Caribbean that the French island of Guadeloupe issued a health alert at the end of July. He warned some communities about high levels of hydrogen sulfide emanating from huge clumps of rotting algae, which can affect people with respiratory problems, including asthma.

The Biden administration has declared a federal emergency after the US Virgin Islands warned last month of “unusually high amounts” of sargassum affecting water production at a desalination plant near St. Croix that is struggling to meet demand. demand in times of drought.

“We are consuming as much as we can produce right now,” said Daryl Jaschen, director of the islands’ emergency management agency. “We are very concerned about this.”

Additionally, the US Virgin Islands Power Plant relies on ultra-pure water from the desalination plant to reduce emissions monitored by the US Environmental Protection Agency. The loss of that water would force the government to use a more expensive type of diesel fuel in limited quantities, officials said.

Experts first noted large amounts of sargassum in the Caribbean Sea in 2011, which Hu and other scientists believe were created by stronger-than-normal winds and currents. The problem worsened as the clumps multiplied, fueled by nutrients and strong sunlight.

“In the tropical Atlantic, everything was fine,” Hu said. “Everything grows fast.”

Sargassum eaten in moderation helps purify water, absorb carbon dioxide, and is key habitat for fish, turtles, shrimp, crabs, and other creatures. But it’s bad for tourism, the economy and the environment when too much accumulates just offshore or on the beaches.

A carpet of brown algae recently surrounded an uninhabited island near the French Caribbean territory of St. Maarten that is popular with tourists, forcing authorities to suspend ferry service and cancel kayaking and snorkeling excursions. The normally translucent waters around Pinel Island have turned to a brown, prickly melting snow.

“It’s the worst we’ve ever seen,” said Melody Rouveure, managing director of a travel agency in the Dutch Caribbean territory of St. Maarten, which shares an island with St. Maarten. “It ruined my personal beach plans.”

On Union Island, part of St. Vincent and the Grenadines, the invasion of algae forced some resorts to close up to five months in the past.

Masses of sargassum have also strangled the Caribbean fishing industry. It damages boat engines and fishing gear, prevents fishermen from reaching their boats and fishing grounds, and leads to a drop in the number of fish caught. Barbados has been particularly hard hit as flyingfish make up 60% of the island’s annual landed catch, according to the University of the West Indies.

An overabundance of sargassum has been blamed for the recent death of thousands of fish on the French Caribbean island of Martinique. It also has activists concerned about the plight of endangered turtles, with some dying at sea entangled in seaweed or unable to lay their eggs given the carpet of seaweed covering the sand.

In the Cayman Islands, a thick mat of sargassum had prompted officials to launch a test program in which crews pumped more than 2,880 square feet (268 square meters) of algae out of the water. But on Tuesday the government announced it was suspending removal efforts because the level of decay made it impractical.

“The sargassum stranding in the North Sound is unlike any we’ve seen before in location, weather and scale,” officials said.

Other island nations have opted to use heavy machinery to remove seaweed from the beach, but scientists warn this is causing erosion and could destroy endangered turtle nests.

Attempts to use sargassum as a fertilizer, food, biofuel, building material or medicine continue, but many Caribbean islands are unable to remove the large amounts of algae because they have financial difficulties and have resources limited.

Governor Albert Bryan of the U.S. Virgin Islands said he asked President Joe Biden to declare a federal emergency for all three islands, not just St. Croix, but that didn’t happen. Bryan said he is now trying to find local funds to clean up the beaches, “but a lot of things need money right now.”

Since 2011, large amounts of Sargassum have invaded the Caribbean every year except 2013 – an anomaly which scientists believe could be due to a lack of nutrients and a change in wind strength and direction. And the record amounts reported in recent years are of even greater concern to scientists and island governments.

“We don’t know if this is a new normal,” Krimsky said. “It’s been devastating for over a decade.”