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

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 phytoplankton …

—Usha Lee McFarling

compare zooplankton

phytoplanktonic

ˌfī-tō-plaŋ(k)-ˈtä-nik 

adjective

phytoplanktonic species

a phytoplanktonic bloom

Examples of phytoplankton in a Sentence

Recent Examples on the Web

One species of bioluminescent phytoplankton called Pyrocystis noctiluca does this by ballooning six times its normal size. —Laura Baisas, Popular Science, 17 Oct. 2024

On bright sunny days, schools of baitfish will move to the top of the water column to feed on phytoplankton. —Kubie Brown, Outdoor Life, 3 Oct. 2024

During photosynthesis, phytoplankton consume CO2, sunlight and nutrients, including iron. —Alec Luhn, Scientific American, 12 Sep. 2024

That’s important because each phytoplankton community may play different roles in ecosystems and food chains. —Dinah Voyles Pulver, USA TODAY, 30 Jan. 2024

Word History

Etymology

phyto- + plankton

First Known Use

1897, in the meaning defined above

Kids Definition

phytoplankton

noun

phy·​to·​plank·​ton ˌfī-tō-ˈplaŋ(k)-tən 

-ˌtän

: plankton that is composed of plants