Dinoflagellate

Dinoflagellate, any unicellular aquatic organism order Dinoflagellida, class Phytomastigophorea, subphylum Mastigophora, with two uneven flagella for locomotion. Many forms have a cellulose casing of numerous plates or a two-part shell. Several thousand species of dinoflagellates are known. Most, but not all, contain chlorophyll and are photosynthetic. Among these are the diatoms, which are the primary producers of energy in the ocean food chain. Like many complex one-celled organisms, dinoflagellates show traits of both animals and plants; they are claimed by zoologists as protozoans and by botanists as algae. In this encyclopedia they are placed in the kingdom Protista. They are mostly marine creatures, and in warm, shallow waters they sometimes reproduce in enormous numbers, called a bloom. Certain species of the genera Gymnodinium and Gonyaulax produce a strong nerve toxin and are responsible for the blooms called red tides (see Plankton). These blooms have caused the deaths of large numbers of fish and have contaminated clams and mussels, which may be lethal to humans who eat them. Many species of dinoflagellates produce bioluminescence. See also Flagellates.