phytoplankton
noun
phy·to·plank·ton
ˌfī-tō-ˈplaŋ(k)-tən 
-ˌtän
plural phytoplankton also phytoplanktons
: minute aquatic photosynthetic organisms (such as dinoflagellates, diatoms, and cyanobacteria) : photosynthetic plankton of freshwater or marine environments
Twenty to 40 different species of phytoplankton … can coexist within a single cubic centimeter of water, all vying just for light and a handful of nutrients.—
O. Baker
O. BakerPhytoplankton—myriad small, mostly unicellular algae and bacteria that occupy the surface waters of seas and lakes—dominate aquatic primary production, and over time they have radically altered Earth's atmosphere.—Robert Riding
Robert RidingPhytoplankton form the foundation of marine food chains, and their seasonal blooms are responsible for more than half the photosynthesis, and the resulting production of oxygen, that occurs on Earth.—Robin George Andrews
Robin George AndrewsAntarctic krill are thumb-sized crustaceans that feast on drifting phytoplankton …—Usha Lee McFarling
compare zooplankton
Usha Lee McFarlingExamples of phytoplankton in a Sentence
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The onboard specialists guide the landings and shore excursions, including studying phytoplankton and native coral, implementing bird-strike reduction efforts and discovering new penguin colonies.
—Martie Bowser, Forbes.com, 1 May 2025
The molecules, dimethyl sulfide and potentially dimethyl disulfide, are typically made by marine phytoplankton on Earth.
—Ashley Strickland, CNN Money, 19 Apr. 2025
So Tyler Coale, a phytoplankton biologist at UC Santa Cruz, pored over the inner workings of both by analyzing their proteins.
—Ari Daniel, NPR, 18 Mar. 2025
During a bloom, environmental conditions cause microscopic phytoplankton to proliferate.
—Sarah Kuta, Smithsonian Magazine, 27 Mar. 2025
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Martie Bowser, Forbes.com, 1 May 2025
The molecules, dimethyl sulfide and potentially dimethyl disulfide, are typically made by marine phytoplankton on Earth.
—Ashley Strickland, CNN Money, 19 Apr. 2025
So Tyler Coale, a phytoplankton biologist at UC Santa Cruz, pored over the inner workings of both by analyzing their proteins.
—Ari Daniel, NPR, 18 Mar. 2025
During a bloom, environmental conditions cause microscopic phytoplankton to proliferate.
—Sarah Kuta, Smithsonian Magazine, 27 Mar. 2025
See All Example Sentences for phytoplankton
Cite this Entry
“Phytoplankton.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/phytoplankton. Accessed 20 May. 2025.
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phytoplankton
noun
phy·to·plank·ton
ˌfī-tō-ˈplaŋ(k)-tən
-ˌtän
: plankton that is composed of plants
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