The Word of the Day comes from "the stranger in the lifeboat" by Mitch Albom
The dinoflagellates (Greek δῖνος dinos "whirling" and Latinflagellum "whip, scourge") are monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and usually considered algae. Dinoflagellates are mostly marineplankton, but they also are common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy and myzocytosis).
A rapid accumulation of certain dinoflagellates can result in a visible coloration of the water, colloquially known as red tide (a harmful algal bloom), which can cause shellfish poisoning if humans eat contaminated shellfish. Some dinoflagellates also exhibit bioluminescence—primarily emitting blue-green light. Thus, some parts of the Indian Ocean light up at night giving blue-green light.