red tide

noun

: seawater discolored by the presence of large numbers of dinoflagellates (as of the genera Karenia, Gymnodinium, and Alexandrium) which typically produce a toxin poisonous especially to many forms of marine vertebrate life and to humans who consume contaminated shellfish compare saxitoxin

Examples of red tide in a Sentence

Recent Examples on the Web

However, the desire of Vietnamese Americans — who have memories of living under a communist regime and harbor strong anti-communist sentiment — for the U.S. to have a tougher approach to communist governments in China and Vietnam might have driven a red tide in the more recent elections, Bui said. —Hanna Kang, Orange County Register, 9 May 2024

Elsewhere, other threats continued, like collisions with boats and poisoning from red tide, a toxic algae. —Jason Gulley Catrin Einhorn, New York Times, 7 Mar. 2024

Word History

First Known Use

1904, in the meaning defined above

Kids Definition

red tide

noun

: seawater discolored and made poisonous by the presence of large numbers of dinoflagellates

Medical Definition

red tide

noun

: a large area of seawater discolored by the presence of large numbers of dinoflagellates (as of the genera Karenia, Gymnodinium, and Alexandrium) which typically produce toxins poisonous especially to many forms of vertebrate marine life and to humans who consume contaminated shellfish

In simple terms, a red tide is a dinoflagellate population explosion, caused when certain species "bloom," or multiply many times faster than usual.

—Ellen Girardeau

Red tides, the blooms of toxic Karenia brevis algae that appear almost every year in Florida, often lasting for months and turning the ocean red, may be dangerous to asthma sufferers—even if they don't go swimming.

—Nicholas Bakalar

see brevetoxin, saxitoxin, shellfish poisoning