Definition of plankton in US English:



  • The small and microscopic organisms drifting or floating in the sea or fresh water, consisting chiefly of diatoms, protozoans, small crustaceans, and the eggs and larval stages of larger animals. Many animals are adapted to feed on plankton, especially by filtering the water.

    Compare with nekton
    • ‘They have no teeth, and feed by ‘hoovering up’ tiny plankton from the sea.’
    • ‘The eggs and young, which hatch in around two weeks, drift in the Oceans currents feeding upon plankton for the first few months of their life.’
    • ‘The production of plankton is directly related to the fertility of the water.’
    • ‘The young remain in the water column feeding on plankton until they are around 50 mm in length.’
    • ‘However, the seaweeds or the algae and in particularly the microscopic plankton can fix a lot more carbon than a forest can.’
    • ‘Every March and April, whale sharks come to Ningaloo Reef on Australia's outback coast to feed on plankton.’
    • ‘Scientists say that the change in species of plankton, from cold water types to warm water, are less favourable to cod in its juvenile stage.’
    • ‘The fish then turn to feeding on larger plankton, including small fish, before migrating down into the depths at around two years of age.’
    • ‘The significance of this is that other species such as shellfish and crustaceans feeding in plankton could be affected.’
    • ‘These regions of high productivity promote the development of plankton, which feeds planktivorous fish such as anchovies.’
    • ‘In the newly exposed waters and throughout the North Atlantic Ocean, plankton growth is prodigious.’
    • ‘Microscopic plankton trapped in the finely tipped gills are pulled slowly into waiting mouths.’
    • ‘Whales eat big fish, which eat medium fish, which eat small fish, which eat smaller fish, which eat plankton.’
    • ‘They may also forage for insects, plankton, mollusks, crustaceans, and small fish.’
    • ‘Smaller warm water plankton has replaced them and they are less nutritious, according to the scientists.’
    • ‘The plankton that permeates these waters attracts vast swarms of anchovies, which in turn draw millions of seabirds.’
    • ‘Manta rays live in tropical waters and feed on plankton, using their frontal flaps.’
    • ‘Each oyster feeds naturally on plankton brought in on the tide until the time comes for them to be lifted, washed and packed.’
    • ‘The dung feeds microscopic plankton, which are consumed by worms and larvae.’
    • ‘The expedition also found rings of plankton organisms that measured 10 km wide.’
    • ‘All plankton, kelp forests and seagrass beds are found in the euphotic zone.’


Late 19th century: from German, from Greek planktos ‘wandering’, from the base of plazein ‘wander’.