On the contrary, these microscopic algae constitute the base of the marine food chain, supporting the great mass of life in the ocean. It is simply an unfortunate coincidence that out of the thousands of species of phytoplankton a few produce substances that are strongly poisonous to humans. However, this picturesque name is misleading because there's no reliable connection between red-colored water and toxicity. Ditto for nontoxic blooms. When they feed on a toxigenic species of phytoplankton, they accumulate the toxin in their tissues.
Coastal states maintain a constant vigilance to prevent outbreaks of shellfish poisoning.
Since there's no way to control the toxic blooms, protective programs focus on making sure that no one consumes toxic shellfish. State shellfish agencies regularly test shellfish so they can detect toxicity before it rises to dangerous levels and close shellfish beds in time to prevent illness. Respiratory failure in severe cases. Can be fatal. Permanent memory loss in severe cases.