WASHINGTON – Researchers have finally confirmed a 20-year-old theory about how the red tide algae produce their toxins.

The finding may be a first step in protecting seaside communities, shellfish beds, marine mammals and humans from the periodic outbreaks of the dangerous tides.

Red tides are natural occurrences, when water temperature and salinity encourage overproduction of some algae and plankton. Not all red tides are poisonous, but some are.

A massive red tide struck from Maine to Cape Cod in 1972, and others have occurred in the region since. Red tide has killed manatees in Florida. And some speculate that the Bible’s first plague of ancient Egypt – when the water turned to blood – was a red tide.

Associate professor Timothy F. Jamison at the Massachusetts Institute of Technology reports in today’s edition of the journal Science that researchers have managed to duplicate a cascade-type chemical reaction to produce the red tide toxins.

In 1985 chemist Koji Nakanishi of Columbia University suggested that the algae used a cascade of chemical steps to produce red tide toxins. But until now, researchers have been unable to demonstrate such a reaction in the laboratory.

Jamison and graduate student Ivan Vilotijevic were able to jump-start the reaction, which then proceeded to form the chemicals. A key was conducting the reaction in water, Jamison said.

Most reactions are tested in organic solvents, but they found that when water was added the reaction took place more quickly and directly.

“The trick is to give it a little push in the right direction and get it running smoothly,” Jamison said in a statement.

He speculated that the dinoflagellates which produce the chemicals in nature jump-start the reaction using an enzyme.

One of the chemicals produced is brevenal, which is related to the red tide toxins, but has shown to have potential as a treatment for cystic fibrosis.

“Now that we can make these complex molecules quickly, we can hopefully facilitate the search for even better protective agents and even more effective [cystic fibrosis] therapies,” Jamison said.

The research was funded by the National Institute of General Medical Sciences, Merck Research Laboratories, Boehringer Ingelheim and MIT.