phy·​to·​plank·​ton ˌfī-tō-ˈplaŋ(k)-tən How to pronounce phytoplankton (audio)
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
Phytoplankton—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
Phytoplankton 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
Antarctic krill are thumb-sized crustaceans that feast on drifting phytoplanktonUsha Lee McFarling
compare zooplankton
phytoplanktonic adjective
phytoplanktonic species
a phytoplanktonic bloom

Examples of phytoplankton in a Sentence

Recent Examples on the Web The bloom could include blue-green algae, known as cyanobacteria, along with other types of phytoplankton, NASA said. Don Sweeney, Sacramento Bee, 2 June 2024 Inspired by the way in which phytoplankton harnesses sunlight for energy, the hybrid-electric Blue cruisers use solar panels to capture clean energy and then stores it in advanced batteries to power the engines and hotel load. Rachel Cormack, Robb Report, 20 May 2024 Other projects, like collecting phytoplankton readings using a Secchi Disk, may require a few more tools. Alisha McDarris, Popular Science, 20 Mar. 2024 Learn more about the complexities of phytoplankton behavior — from their intricate swimming patterns to their nutrient absorption strategies — and understand their impact on marine ecosystems. David L. Coddon, San Diego Union-Tribune, 22 Feb. 2024 See all Example Sentences for phytoplankton 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'phytoplankton.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


phyto- + plankton

First Known Use

1897, in the meaning defined above

Time Traveler
The first known use of phytoplankton was in 1897

Dictionary Entries Near phytoplankton

Cite this Entry

“Phytoplankton.” Dictionary, Merriam-Webster, Accessed 12 Jun. 2024.

Kids Definition


phy·​to·​plank·​ton ˌfī-tō-ˈplaŋ(k)-tən How to pronounce phytoplankton (audio)
: plankton that is composed of plants

More from Merriam-Webster on phytoplankton

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!