|Darcizzle appreciates Sargassum|
A giant seaweed blob so large it can be seen from space is threatening to transform beaches along Florida’s Gulf coast into a brown morass, scientists say.
The 5,000-mile-wide sargassum bloom — believed to be the largest in history at twice the width of the continental US — is drifting ominously toward the Sunshine State, NBC News reported.
“It’s incredible,” Brian LaPointe, a research professor at Florida Atlantic University’s Harbor Branch Oceanographic Institute, told the news outlet.
“What we’re seeing in the satellite imagery does not bode well for a clean beach year,” he added.
The thick algae mats are mostly harmless as they drift between Africa’s western coast and the Gulf of Mexico — and even provide a habitat for certain marine life and absorb carbon dioxide.
LaPointe said massive piles typically wash ashore in South Florida in May, but the algae are already inundating beaches in Key West.
Brian Barnes, an assistant research professor at the University of South Florida’s College of Marine Science, told NBC News that the sargassum can cause major problems even in coastal waters.
“[I]t can block intake valves for things like power plants or desalination plants. Marinas can get completely inundated and boats can’t navigate through,” he said.Hogchokers clogging power plants.
“It can really threaten critical infrastructure,” Barnes added.
More than a decade ago, scientists noticed that the unsightly blooms were beginning to grow at alarming rates. They have since documented their proliferation in the tropical Atlantic.
“Before 2011, it was there but we couldn’t observe it with satellites because it wasn’t dense enough,” Barnes told NBC News. “Since then, it has just exploded and we now see these huge aggregations.”
In 2019, a study in the journal Science estimated that more than 20 million metric tons covered the Atlantic in what has been dubbed the “Great Atlantic Sargassum Belt.”
Researchers have found that human activities and climate change are filling rivers that flow into the Atlantic with nitrogen and other nutrients.
Of course, the center of the mid-Atlantic gyre is often called the Sargasso Sea because of the large matts of Sargassum found there. It was well known in the old days for light winds, and sailing ships were sometime becalmed there for long periods. The water in the central gyres is warm, and very low in nutrients. Nevertheless, Sargassum thrives there (possibly in conjunction with a nitrogen fixing blue-green alga Trichodesmium), so it's dubious that higher nutrients are the reason.
FWIW, the year we moved to Florida, the local beaches were knee-deep in seaweed for a while. But it wasn't Sargassum, it was several species of red algae.