Gigantic seaweed bloom affecting Florida coasts

Scientists just discovered the largest seaweed bloom in the world, and it’s washing up on Florida’s coasts. 

University of South Florida researchers found the seaweed might become part of our new normal, potentially causing problems for marine life and humans. 

“We have discovered there was a huge amount of sargassum over the central Atlantic, the Caribbean Sea and the Gulf of Mexico,” said Mengqiu Wang, a post-doctoral researcher at USF who worked on the study.

The seaweed belt is about 5,500 miles long and weigh about 20 million tons, and it’s called the Great Atlantic Sargassum Belt. Its growth was tracked using satellite images from 2011 to 2018.

“Sargassum in open water is actually a good thing. It's associated with great ecological values by providing essential habitat and refuge to marine life like the sea turtles,” said Wang.

Small amounts are good, but large sections can kill some marine life like coral reefs and sea grass, Wang said. It can also cause problems for humans.

The seaweed is washing up on beaches along Florida’s east coast and smells like rotten eggs.

“People can have breathing problems. For people that have asthma that can cause severe health problems,” she said.

It can also impact livelihoods.

“It can also be affecting the fisheries, and it's actually happening in a lot of the Caribbean islands,” Wang said.

Scientists believe deforestation in the Amazon may be a reason why the seaweed belt forms in the summer. 

“People cutting down trees and also the fertilizer consumption, all of those human-induced factors leads to more nutrient supply into the open ocean, which eventually stimulates the sargassum growth,” said Wang.

Researchers said it’s hard to predict where it may show up next, but they hope their findings will help.

Pinellas County government said a small amount of the sargassum seaweed recently showed up in Clearwater, so they are monitoring the shores. 

Researchers said they send some projected information on the seaweed flow to the public to help local cities and travelers plan.