'Red tide' organism deadlier than thought

July 24, 2012 at 3:03 PM
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STORRS, Conn., July 24 (UPI) -- A tiny aquatic organism in algal blooms known as "red tides" is even deadlier than thought and could affect entire marine food chains, U.S. scientists say.

A University of Connecticut researcher and his team have discovered the plankton species Alexandrium tamarense contains not one but two types of toxins. One is deadly to large organisms and one kills small predators.

"If it's killing multicellular animals with one toxin and small [single cell] protists with another, it could be the killer of the ocean world," marine scientist Hans Dam said in a university release.

This ability to harm both large and small oceanic predators could lead to disruptions in the marine food web during large blooms such as the red tide that occurred along the Northeast coast in 2005, severely affecting the Cape Cod area, Dam said.

While Alexandrium are normally harmless to humans in small numbers, Dam said, when they're eaten by other clams, mussels or other microorganisms -- which are then eaten by small crustaceans that in turn are consumed by larger crustaceans or fish -- the toxins can build up in large amounts.

In some parts of the world, eating contaminated shellfish, such as lobsters, clams and fish, has led to illness or death, he said.

"The amazing thing is, when you look at these algae under a microscope, they're so beautiful -- but they're so deadly," Dam said. "We call them the beautiful assassins."

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