seston
All particulate matter suspended in bodies of water such as lakes and seas, including plankton, organic detritus, and inorganic material.
countable, uncountable
Depending on mesh size and the area of investigation, net samples contain a variable mixture called seston. […] Nowadays plankton stands for the living part of seston, detritus for dead organic and inorganic particles.
Where it comes from
From German Seston, by surface analysis, Ancient Greek σηστός (sēstós, “sifter”, verbal adjective of σήθω (sḗthō, “I strain, filter”)) + -on. Compare plankton.
Adapted from the Wiktionary entry seston (CC BY-SA 4.0).