8.7 million tons of seaweed headed to Florida waters this summer

An 8.7 million ton seaweed blob is expected to arrive on Florida beaches ahead of the summer tourist season.

Anthony Jackson, USA TODAY

Beachgoers in Florida and the Caribbean could be greeted by heavy blankets of smelly seaweedin the weeks ahead as a 5,000 mile swath of sargassum drifts westward and piles onto white sandy beaches.

Sargassum, a naturally-occurring type of macroalgae, has grown at an alarming rate this winter.The belt stretches across the Atlantic Ocean from Africa to Florida and the Yucatan Peninsula and is as much as 200-300 miles wide.

"This year could be the biggest year yet," even bigger than previous upticks,said Brian Lapointe,an algae specialist and research professor at Florida Atlantic University's Harbor Branch Oceanographic Institute.

It's already beginning to wash upin the Florida Keys and Barbados and elsewhere in the region, but researchers don't know where the bulk of it could wind up.

How does climate change affect you?: Subscribe to the weekly Climate Point newsletter

READ MORE: Latest climate change news from USA TODAY

The monstrous seaweed bloom is just one more example of a growing global invasion of macro and microscopic algal blooms thriving on an increasing supply ofnutrients such as nitrogen in freshwater and marine ecosystems.

In addition to the unsightly piles of sargassum along the coast, some species produce toxins that affect the food chain or deplete the oxygen in the water when they start to decay, causing fish kills and the die off of other marine species.

Here's what to know:

Not all algal blooms are bad. Many can occur naturally, and can havepositive effects.

FOR SUBSCRIBERS: Huge seaweed blob on way to Florida is 'like a Stephen King movie'

Yes. Christopher Columbus wrote about floating mats of it in the Atlantic Ocean.

"It's not a bad thing to have the sargassum in the ocean," said Brian Barnes, an assistant research professor at the University of South Florida in Tampa. Sea turtle hatchlings swim from Florida beaches to the Sargasso Sea in the Atlantic where they spend their early lives floating and foraging in the grass.

"If it all stays offshore , we wouldn't really have a problem," Barnes said.But the macroalgae has mushroomed in size, over the past12 years or so, making it more likely to see large piles of seaweed that make it difficult to walk, sit or play onbeaches.

The trend was first documented on satellite in 2011.

In some cases, there's so much seaweed, local governments must useheavy equipment anddump trucks to haul it away, LaPointe said.

He has linked the surge in sargassum to flow from the Mississippi River, extreme flooding in the Amazon basin, as well as to themouth of the Congo where upwelling and vertical mixing of the ocean can bring up nutrients that feed the blooms. He said deforestation and burning also may contribute.

DEFINITIONS: Is climate change the same thing as global warming? Definitions explained.

CLIMATE CHANGE CAUSES: Why scientists say humans are to blame.

Blooms of much smaller algae amicroscopic species known asphytoplankton increased in size and frequency around the world between 2003 and 2020, the researchers concluded in the Nature study.

"Weve seen something pretty similar ina lot of the things we study," saidBarnes."Were seeing such massive blooms now."

The coastal phytoplankton study, by Lian Feng at the Southern University of Science and Technology in China, and others, used images from NASAs Aqua satellite. They found:

Blooms have been at least indirectly linked to climate change in several ways, but especially to thewarming temperatures that bring more extreme rainfall that washes silt and pollutants into waterways.

FOR SUBSCRIBERS: Saving endangered right whales pits advocates against lobstermen

GREEN ENERGY: Growing group of mayors at odds with experts over whale deaths and offshore windmills

The authors of the coastal phytoplankton study, Lapointe and other researchers have found the following:

"We can't really say which particular beach at which particular time," Barnes said. The University publishes a regular update on the status of the sargassum bloom.

"We can get an idea of when it will be fairly close," he said. "In general, everything flows west. It will come across the Central Atlantic and into the Caribbean, and into the Gulf of Mexico through the straits of Florida."

Winds, currents and even small storms can influence where the sargassum moves.

Puerto Rico and the U.S. Virgin Islands could get hit pretty hard, Barnes said. But the floating matsalso wind up on beaches in Jamaica and all around the coast of Florida.

View post:

Smelly seaweed sargassum headed toward Florida, the Caribbean ... - USA TODAY