Dinoflagellates are single-celled organisms of the Division Pyrrhophyta. Most people, although not familiar with dinoflagellates, are familiar with their effects. Bioluminescent dinoflagellates cause a sparkling of the sea at night as the waves break, and certain dinoflagellates may produce blooms called “red tides,” which poison marine life or which cause toxins to accumulate in shellfish, poisoning those who eat them. The Old Testament (Exodus 7:20–21) and the writings of the ancient Greeks refer to red water and the killing of fish. The Red Sea may have gotten its name from dinoflagellate blooms.