Some reports have also raised fears of “flesh-eating bacteria” among algae, but there is no evidence for this. When people come in close contact with rotting sargassum, they experience health problems, including diarrhea, vomiting, and eye irritation, so sometimes it’s more than just a nuisance. In addition, while local authorities have spent millions removing sargassum from beaches, they have often captured large amounts of sand in the process, which hastened beach erosion.
Because of the issues caused by seaweed, researchers are looking for better ways to monitor its movements so they can understand what factors influence the size—and trajectory—of sargassum blooms.
“This year has been amazing,” said Gustavo Goni, of the National Oceanic and Atmospheric Administration’s (NOAA) Atlantic Oceanographic & Meteorological Lab, recalling the record number of sargassum that scientists saw floating in the ocean in the first few months. in 2023. a peak around March, then, in a strange twist, the sargassum glut began to decline.
NOAA publishes a regularly updated sargassum report online that estimates the risk of coastal flooding around the Gulf of Mexico. The administration collaborated with the University of South Florida to produce this information, and the university also posted separate data obtained from satellite monitoring. It reveals that the sargassum belt will be wider in May of 2018, 2021, and 2022, while in May 2023 it will be less, although not by much. “This year is still a major year for sargassum,” said Chuanmin Hu of the University of South Florida.
Satellite-derived snapshots of seaweed spread are important, but they don’t reveal what the inundations are like on land. Hu and his colleagues collected data from the field, but members of the public also played a role. “We really need citizen science,” Goni said, noting that people can send photos and videos of seaweed to NOAA through the sargassum report web page. Jimenez-Mariani added that he often shares reports on scientists’ views.
Hu says many factors can influence the growth and flow of sargassum, as well as whether it actually reaches the beach—from light to ocean currents, wind, temperature, and tides.
To better track the movement of seaweed—before it causes issues on land—Linda Amaral-Zettler of the Royal Netherlands Institute for Sea Research and colleagues are working on ways to tag sargassum, or planting drifters in the middle of the big. floating bunches of it. “The idea is to stick one on a patch and move it with a patch,” he said of the drifter devices they are developing.
The tricky part is that the floating sargassum always sinks after a little while. “The probability of losing a tag is pretty high,” Amaral-Zettler said. He says there are more than 350 species of sargassum, but most never float to the surface—only a few species are responsible for the massive drifts that cause problems for tourists and locals alike. in coastal towns in recent years. Away from the beaches, sargassum provides important habitat for turtles and some fish.
