Brown Blob in IRL

Lagoon's brown blob identified

BY JIM WAYMER
Florida Today

January 23, 2008

Scientists have identified the brown blob that floated across the Indian River Lagoon in northern Brevard this month as an extreme case of a common algae.

Researchers identified the algae as a species somewhat related to red tide but without the toxic effects.

The brownish algae frothed up into thick, gelatinous globs that blanketed the lagoon's banks from Melbourne to Titusville.

It stunk up neighborhoods, suffocated fish and worried riverside residents, until the algae clumps broke up or sank to the bottom after several days.

The University of Florida biologists who identified the algae suspect high levels of nutrients in the lagoon and a quick cold snap may have caused the algae to bloom then die off drastically, said Bob Day, an environmental specialist.

Day is with the St. Johns River Water Management District's Indian River Lagoon program.

"They theorized the weather may have played a role in it," Day said.

The algae belongs to a similar class of algae as red tide, called diatoms, which have cells covered in an armor-like silicon shells.

The Gonyaulax bloom exploded just as a two-month red tide bloom waned in the lagoon region.

Unlike red tide, Gonyaulax blooms in Florida do not produce toxins, according to the Fish and Wildlife Research Institute in St. Petersburg.

But the algae can trigger huge fish and invertebrate kills by causing the oxygen in the water to drop and sulfide and ammonia levels to spike as its dying cells rot.

Gonyaulax polygramma is found worldwide in cold to tropical waters, according to the wildlife research institute, and grows best from 63 to 73 degrees Fahrenheit.

The algae can produce flashes of bluish glow at night, or bioluminescence, in shallow waters when fish swim through it.

In July 2002, the algae bloomed at high levels in the lagoon, killing about five dozen finger mullet near Patrick Air Force Base, according to a state database.