It's estimated that the red tide algae, Karenia brevis, costs approximately $20 million per bloom in economic damage off the coast of Florida alone. Scientists at the Georgia Institute of Technology have found that a diatom can reduce the levels of the red tide's toxicity to animals and that the same diatom can reduce red tide's toxicity to other algae as well. If scientists can learn to use this process to reduce the toxicity of red tide, they could reduce the vast amount of economic damage done to the seafood and tourism industries. The research appears as articles in press for the Web sites of the journals Harmful Algae and the Proceedings of the Royal Society of London B.
"We found that red tide toxins can be metabolized by other species of phytoplankton. That holds true for both the brevetoxins that damage members of the animal kingdom and the as yet unknown allelopathic toxins that kill other competing species of algae," said Julia Kubanek, an associate professor with a joint appointment in Georgia Tech's School of Biology and School of Chemistry and Biochemistry.
Red tide is a dramatic case of an ecosystem that's out of control. In normal seawater, K. brevis makes up about 1 percent or less of the species, but during a red tide, that share increases to more than 90 percent. Filter feeders such as oysters, mussels and clams ingest the dinoflagellate and become unsafe to eat. Fish killed by the red tide wash on the shore, which can be contaminated and essentially unusable to tourists for months at a time.
Kubanek and her researchers found in previous work that the growth of the diatom Skeletonema costatum was only moderately suppressed by the brevetoxins released by the red tide. So, they figured that the diatom might have a way to deal with the toxins. According to their study, they were right.
In one experiment, detailed in the journal Harmful Algae, Kubanek's students grew the red tide algae alo
|Contact: David Terraso|
Georgia Institute of Technology