Pseudo-nitzschia

Pseudo-nitzschia is a genus of marine planktonic diatoms, making up roughly four and a half percent of pennate diatoms worldwide across fifty-eight known species, of which twenty-eight are capable of producing the neurotoxin domoic acid. That toxin causes amnesic shellfish poisoning in humans who eat contaminated shellfish, and the genus drew wide scientific attention after a 1987 bloom off Prince Edward Island, Canada, sickened more than a hundred people who had eaten tainted mussels and killed three, the first recognition that diatoms, not only dinoflagellates, could produce harmful algal toxins. Toxic blooms of the genus have since been documented worldwide and linked to nutrient pollution, warming ocean temperatures and interactions with certain bacteria. The genus was separated from the related genus Nitzschia in 1994 based on its distinctive chain-forming cells and other morphological differences.