red tide

noun

Definition of red tide

: 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

The red tides are unpredictable and not all produce a bioluminescence. CBS News, "Bioluminescence from red tide: Algae bloom literally lighting up San Diego waves at night," 9 May 2018 The decree is not involved with other water problems that plagued Florida coasts last year, including red tide outbreaks and algae blooms. Curt Anderson, The Seattle Times, "Judge won’t end decades-old Everglades cleanup oversight," 11 Feb. 2019 Environmental concerns have been a major issue in the campaign because of an outbreak of blue-green algae and red tide, which produces toxic chemicals blamed for killing fish, sea turtles, dolphins and other animals. Arian Campo-flores, WSJ, "Florida Senate Seat Becomes Year’s Most Expensive Race," 26 Oct. 2018 The current red tide has lasted about a year so far, the longest stretch in more than a decade, and has spread from the west coast to the east, hurting the tourism industry. Arian Campo-flores, WSJ, "Florida Senate Seat Becomes Year’s Most Expensive Race," 26 Oct. 2018 For humans, red tide can cause respiratory irritation to those on shore, itchy skin or a burning sensation in the eyes of swimmers. Sebastian Modak, Condé Nast Traveler, "Florida Hit By Worst 'Red Tide' Bloom in Over a Decade," 3 Aug. 2018 Statistics from the Florida Fish and Wildlife Conservation Commission say that red tide is to blame for at least 97 manatee deaths. Tamara Lush, The Seattle Times, "In first 8 months of year, manatee death toll surpasses 2017," 20 Aug. 2018 Officials are now trying to figure out why this year's red tide is so intense. Travis Fedschun, Fox News, "Red tide along Florida's Gulf Coast leads Gov. Scott to declare state of emergency," 15 Aug. 2018 The blue-green algae is different from the red tide algae bloom that has devastated marine life on Florida’s Gulf Coast. James Rogers, Fox News, "Blue-green toxic algae invades Florida river," 15 Aug. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'red tide.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of red tide

1904, in the meaning defined above

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Last Updated

23 Apr 2019

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The first known use of red tide was in 1904

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red tide

noun

Medical Definition of red tide

: 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

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