What is "picoeukaryote"

n. (context biology English) Any eukaryotic organism that ranges in size from 0.2 – 2.0 µm.

Picoeukaryotes are picoplanktonic eukaryotic organisms that range in size from 0.2 – 2.0 µm. They are distributed throughout the world’s marine and freshwater ecosystems and constitute a significant contribution to autotrophic communities. Though the SI prefix pico- might imply an organism smaller than atomic size, the term was likely used to avoid confusion with existing size classifications of plankton.