Definition of picoplankton in English:

picoplankton

Pronunciation /ˈpiːkəʊˌplaŋ(k)tən/

noun

Biology
  • Plankton consisting of organisms between 0.2 and 2.0 microns in diameter, or having a wet weight of the order of 10−12 g.

Origin

1970s. From pico- + plankton.