View Full Version : Algae choking Breton, Chandeleur sounds

08-12-2010, 07:17 AM
It's not oil, it's algae and that's not necessarily good news.
That was the message Wednesday from LSU scientists looking at samples from a vast area of red-colored water that has been spreading rapidly across Breton and Chandeleur sounds since last week.
"It's a little unusual to see this type of algae -- a dinoflagellate (http://www.britannica.com/EBchecked/topic/163945/dinoflagellate) -- in the summer, but it's definitely algae, not oil," said Sibel Bargu Ates (http://www.oceanography.lsu.edu/bargu.shtm), an LSU professor and algae specialist.
And while common, if this bloom persists long enough, it could be harmful to fish and, in rare situations, possibly to humans that consume the fish, Bargu Ates said.
"Some dinoflagellates contain toxins that can be harmful to fish that consume them," she said. "And if a human consumes enough fish that have consumed enough toxins, then they could possibly be affected.
"But we have not yet identified what type of dino this is, and if it has any toxins. That could take a day or two."
Although small algae blooms have been reported by fishers for several weeks, environmentalists searching for remnants of the BP oil spill (http://www.nola.com/news/gulf-oil-spill/)last week were alarmed by the size and color of the mass stretching across the Breton-Chandeleur area. The red color matched the hues of BP-generated oil slicks that have floated across the Gulf since the Deepwater Horizon exploded in April.
But Bargu Ates said the water contained algae, and she saw no reason why the BP disaster could be linked to this large outbreak.
Algae blooms are common along the Louisiana coast from spring through fall when the nutrient-rich waters of Louisiana's estuaries provide the perfect combination for algae growth: warm, nutrient rich water form the Mississippi River baking in high heat under long hours of sunlight.
Those conditions allow algae to reproduce rapidly, and a small colony can spread across acres in hours. Big blooms racing across open water eventually collapse as their population outgrows the oxygen supply in the water, said Harry Blanchet, coordinator of coastal fisheries programs for the Louisiana Department of Wildlife and Fisheries.
Fish typically swim away from an outbreak, Blanchet said. But if caught in enclosed areas such as marinas and small lakes, or trapped against banks or beaches, fish kills can result. Fish can die from a lack of oxygen in the water, their gills can become clogged with algae and, in some cases, toxins can paralyze or kill the fish.
Gulf Coast communities have long experienced "seafood jubilees," the term for algae blooms called red tides that result in masses of edible seafood floating to the surface where they can easily be scooped up by residents.
Bargu Ates said it was impossible to forecast the effects of this bloom. And any stormy weather approaching the area could result in significant changes.
"It could stir up nutrients that are on the bottom, putting them back in the upper layer of the water, where they would feed more algae," she said. "Or it could just move the bloom to a new location.
"We just have to wait and see."

08-12-2010, 04:39 PM
i have seen this "red tide" on holly beach a few years back