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
Recent Examples on the Web
The basin is an ideal test site, according to Subhas, because there is little presence of phytoplankton, zooplankton, commercial fish larvae, and endangered species, including some whales, during this season.
—ArsTechnica, 11 Aug. 2025
Since the phytoplankton blooms depend on sunlight, shade slows down their microbial gas and halts the stream of their cloud-making aerosols.
—Max G. Levy, Smithsonian Magazine, 26 June 2025
Additionally, the ocean's phytoplankton and other marine life benefit from the minerals in the dust.
—Leah Sarnoff, ABC News, 4 June 2025
But there’s also phytoplankton and zooplankton — microscopic plants and animals living in the water.
—Sheryl De Vore, Chicago Tribune, 22 July 2025
See All Example Sentences for phytoplankton
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ArsTechnica, 11 Aug. 2025
Since the phytoplankton blooms depend on sunlight, shade slows down their microbial gas and halts the stream of their cloud-making aerosols.
—Max G. Levy, Smithsonian Magazine, 26 June 2025
Additionally, the ocean's phytoplankton and other marine life benefit from the minerals in the dust.
—Leah Sarnoff, ABC News, 4 June 2025
But there’s also phytoplankton and zooplankton — microscopic plants and animals living in the water.
—Sheryl De Vore, Chicago Tribune, 22 July 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 21 Aug. 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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