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 tropical wintering grounds — which have low nitrogen levels — greatly benefit from the whales’ injection of nutrients, which can help grow phytoplankton and microscopic algae and can provide sustenance for fish and sharks.
—Brendan Rascius, Miami Herald, 12 Mar. 2025
Instead, larvae stick to the sea ice, feeding on ice algae until the sun—and the phytoplankton—returns in spring.
—Gabe Castro-Root, Smithsonian Magazine, 11 Mar. 2025
For example, diatoms have a competitive advantage over small phytoplankton under iron-rich conditions in the Southern Ocean.
—Ashley Strickland, CNN, 5 Feb. 2025
The researchers also took regular seawater samples in which to track the amounts of phytoplankton and chlorophyll present over time.
—Asher Elbein, WIRED, 2 Mar. 2025
See All Example Sentences for phytoplankton
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Brendan Rascius, Miami Herald, 12 Mar. 2025
Instead, larvae stick to the sea ice, feeding on ice algae until the sun—and the phytoplankton—returns in spring.
—Gabe Castro-Root, Smithsonian Magazine, 11 Mar. 2025
For example, diatoms have a competitive advantage over small phytoplankton under iron-rich conditions in the Southern Ocean.
—Ashley Strickland, CNN, 5 Feb. 2025
The researchers also took regular seawater samples in which to track the amounts of phytoplankton and chlorophyll present over time.
—Asher Elbein, WIRED, 2 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 25 Mar. 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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