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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
There are tens of thousands of different species of phytoplankton that each have unique interactions with their environment: some beneficial and some potentially harmful, like toxic algal blooms called red tides.
—Justine Calma, The Verge, 8 Feb. 2024
While a red tide is an extreme example, different kinds of phytoplankton can make the surface of the sea appear to be different colors — albeit in ways that are often too subtle for the human eye to detect.
—Justine Calma, The Verge, 8 Feb. 2024
One red tide off of Florida in 2021 left 600 tons of dead fish on the Tampa Bay beaches.
—TIME, 5 Feb. 2024
Five current and former local government officials from across Florida told the Times fertilizer bans are helping their communities decrease pollution that can fuel harmful algal blooms like red tide or toxic blue-green sludge.
—Max Chesnes, Sun Sentinel, 11 Jan. 2024
Wolfe initially feared the color was a sign of a toxic algal bloom, such as the type that produces red tides, per the publication.
—Margaret Osborne, Smithsonian Magazine, 21 Dec. 2023
And then, as soon as the red tide had ebbed, the All Clear was sounded.
—Neal B. Freeman, National Review, 26 Jan. 2024
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'red tide.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
First Known Use
1904, in the meaning defined above
Dictionary Entries Near red tide
Cite this Entry
“Red tide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/red%20tide. Accessed 23 May. 2024.
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
More from Merriam-Webster on red tide
Britannica.com: Encyclopedia article about red tide
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