Practice question

Dinoflagellates, flagellate alveolates bearing two dimorphic flagella within transverse and longitudinal grooves, can proliferate exponentially forming harmful algal blooms termed red tides due to peridinin carotenoid and high cell densities imparting reddish brown discoloration to seawater. Nutrient enrichment, stratification, and temperature favor blooms, some species produce potent neurotoxins saxitoxin, brevetoxin causing paralytic shellfish poisoning, neurotoxic shellfish poisoning, and massive fish kills detrimental to fisheries. Bioluminescent blooms also occur. Mechanism differs from green tides caused by Ulva and golden tides by Sargassum reflecting dinoflagellate ecology.