Large blooms of sargassum algae are clogging the Florida Keys. Brian Lapointe, Ph.D., Florida Atlantic University Harbor Branch Oceanographic Institute For eight years, thick seagrasses have swept over coral reefs, trapping sea turtles and bringing economic instability, reddish-brown odors to coastal communities. Sargassum is washing up on beaches in the Caribbean, Gulf Coast, Mexico, and in the tropical Atlantic "KDSPE" and "KDSPs." These phenomena are all symptoms of an algal bloom that scientists call the Atlantic Sargasso Belt. Researchers describe the band and explore its causes in a study published July 4 in the journal Science. "KdSPE" "KDSPS" Stretching from the Gulf of Mexico to just 5,500 miles (8,850 kilometers) off the west coast of Africa, the North Atlantic Sargassum Belt appears to be the product of natural and human factors.

"We analyzed satellite records from the past 20 years," Mengqiu Wang, a postdoctoral researcher at the University of South Florida and co-author of the study, told Live Science. [Earth from top down: 101 stunning images from orbit]

Researchers analyzed a data set that first appeared back in 2011, allowing them to investigate long-term environmental changes , these changes lay the foundation for annual bloom growth changes.

They identified a tipping point around 2009, when discharges from the Amazon carried unusually high levels of nutrients into the Atlantic Ocean. In the winter of 2010, the upwelling of nutrient-rich water on the west coast of Africa further enriched the deep-sea nutrients of the surface water; the upwelling also lowered the temperature of the surface water, allowing Sargassum to thrive in the summer of 2011.

A similar set of factors led to particularly large blooms in 2014, 2015 and 2017. The largest bloom on record occurred in 2018, when the mass of the Atlantic sargassum belt exceeded 20 million metric tons. The Amazon's high nutrients come from deforestation and fertilizer use in the Amazon basin.

Under normal circumstances, sargassum provides important habitat for marine life. Seaweed oases also attract fish, birds and turtles. Dolphins and sea turtles also benefit from the small pockets of life floating in the open ocean, but Sargassum's thick mats are causing huge problems for some wildlife and coastal communities. "KDSPE" "KDSPs" "KDSPE" Meng Qiuwang was doing field work in the Gulf of Mexico last year when she saw dolphins that seemed to like to feed through sargassum. (University of South Florida)

As the sargassum decays, it consumes oxygen, creating low-oxygen conditions, which are not a good condition for marine life in coastal ecosystems," Wang said. When Gao Coral reef and seagrass ecosystems are affected when concentrations of sargassum alter the water's chemistry, preventing organisms from moving freely

"Sea turtles are sometimes unable to swim through dense mats back to open water after laying eggs. , she said,

The Atlantic sargassum belt is also having an impact on coastal tourism. Barbados declared a state of emergency in 2018 as sargassum accumulated on beaches the island nation relies on to attract tourists, according to a *** statement.

"The negative impact occurs when sargassum starts to accumulate on the beaches," Wang said. In addition to damaging coastal ecosystems, rotting sargassum releases hydrogen sulfide, a potentially harmful gas that smells like rotten eggs. The 10 Weirdest Sea Monsters 13 Bizarre Things Washed Up on the Beach 25 of the Weirdest Spots on Google Earth

Originally published in Live Science.