March 23, 2009

Poisonous Algae Affecting Ocean Creatures

A dangerous nerve toxin emitted by algae off California's coast seems to be distressing creatures in the deep ocean. U.S. researchers believe this poisonous algae is a much larger danger that originally thought.

According to a Reuters report, this algea, known as Pseudo-nitzschia, can create hazardous, large amounts of domoic acid.

"It's a natural neurotoxin. It is produced by a diatom, which is a phytoplankton. As other animals eat this phytoplankton, like sardines or anchovies, this toxin can be transferred up the food chain," stated Emily Sekula-Wood, from the University of South Carolina. Her investigation is published in the journal Nature Geoscience.

Domoic acid is connected to sea lion and whale deaths. It can also affect people who consume a lot of seafood and shellfish.

"If you consume enough of it, you can get brain damage. In humans it's called amnesic shellfish poisoning. You experience short-term memory loss," Sekula-Wood noted.

Oversized blooms of Pseudo-nitzschia have caused several beaches to close down, and have also upset the shellfish industry in the United States.

Sekula-Wood and colleagues investigated the bloom to find out if the toxin was closing in on the ocean floor.

"We used a sediment trap. It is like a rain gauge that you put out in a water," she said to Reuters.

They discovered that huge amounts of domoic acid were falling to the ocean floor, influencing the ocean's food chain.

Unfortunately, the toxin seems to hang around for periods of time.

"Our data further confirm that domoic acid-laced sinking particulates are incorporated into underlying sediments, where they are available for consumption and incorporation into bottom feeders," the researchers wrote.

"It can make us think about the longevity of these toxins," Sekula-Wood added.


Image 2: Chain of Pseudo-nitzschia australis cells under light microscopy.


On the Net: