Dinoflagellates

Dinoflagellates are microscopic, generally single-celled organisms, commonly regarded as algae, ranging from 20 to 150 micrometres and characterized by two flagella that produce a distinctive spiral swimming motion. Abundant in fresh and marine waters, some species generate water-soluble or lipid-soluble toxins harmful to humans and other vertebrates. When they bloom in dense red tides, their toxins contaminate shellfish and fish, triggering the poisoning syndromes that close fisheries and sicken consumers. Their dual flagella and armored plates make them distinctive under the microscope for monitoring laboratories.