Tiny organisms related to coral reefs that are responsible for a number of toxins including saxitoxin (paralytic shellfish poisoning) and ciguatoxin (tropical fish poisoning), and also causing red tides or “reef spawn” in tropical waters.
The appearance of a reddish-brown scum on the surface of the sea caused by dinoflagelates at certain times of the year when heat and other climatic conditions allow for vast expansion in their numbers. Unlike the dinoflagellates that cause PSP, they seems to cause no medical problem apart from irritation of the eyes (conjunctivitis), foul-tasting sea water, and leaving a rotting, unpleasant smell when they dry out on the beach.... red tide
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