Massive algae bloom begins to wash up on Florida beaches

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By Andrew Wulfeck, FOX Weather

March 19, 2023 | 10:31 a.m.

A massive buildup of algae that scientists have been tracking for months has started pouring into the Sunshine State, with experts warning the worst could yet be to come.

Reports from Key West, Fort Lauderdale and other South Florida communities show clumps of brown seaweed piled up along white sand beaches.

Experts from the University of South Florida and other institutions have tracked the sargassum using satellites and estimate the amount of algae in the Atlantic basin to be around 6.1 million tons, the second highest amount ever recorded in February.

Dr. Brian Barnes, an assistant research professor at the University of South Florida’s College of Marine Science, monitors the algae and thinks greater amounts should be offshore in late spring and early summer.

“Larger amounts are expected to be off Florida from about April through July. Most of that, however, will remain offshore. If currents and winds require it, a patch can be pushed ashore to impact on local beaches,” Barnes said.

According to the Florida Department of Health, algae is not harmful to humans, but it can still have impacts.

Besides an unpleasant odor, similar to that of rotten eggs, tiny creatures living in Sargassum can produce rashes and blisters.

Health experts advise people never to eat seaweed as it can also contain high amounts of heavy metals such as arsenic and cadmium.

For many species of sea life, brown algae is actually considered useful, and biologists believe the accumulation provides food and refuge for fish, crabs, shrimp, and other smaller organisms.

Sargassum is quite different from the red tide that simultaneously affects Florida beaches, primarily along the Gulf Coast.

Red tide is a harmful algal bloom and was spotted in the days following Hurricane Ian in Southwest Florida and expanded in early 2023.

The ongoing toxic event has caused hundreds of fish to wash ashore, and biologists believe even manatees have been hit by high levels of the organism known as Karenia brevis.

Specialists have not determined what causes some years to have higher algae production than others, but point to a combination of variable factors, including runoff from major rivers.

“It’s hard to know causation, but, in general, blooms happen when you have the right suite of conditions: temperature, light, a seed, and nutrients,” Barnes said.

As well as being unpleasant to see and smell, algal plumes can cost coastal communities dearly to clean up, and the events can even scare away tourists.

A 2018 effort to clean Caribbean beaches from mass bloom was estimated by the Global Tourism Resilience and Crisis Management Center at more than $120 million, and a study found that a severe year of Sargassum in the south Florida would have similar impacts.

According to a study conducted for the Florida Keys and Monroe County, a major Sargassum event could cost the heavily tourism-dependent region at least $20 million in economic losses and hundreds of local jobs.