Protists are microscopic eukaryotic microbes that are ubiquitous, diverse, and major participants in oceanic food webs and in marine biogeochemical cycles. The study and characterization of protists has a long and distinguished tradition. Even with this history, the extraordinary species diversity and variety of interactions of protists in the sea are only now being fully appreciated. Figure 1 shows representative examples of marine protists, and of methods used to visualize these microbes.

Sherr, B.F., E.B. Sherr, D.A. Caron, D. Vaulot, and A.Z. Worden. 2007. Oceanic protists. Oceanography 20(2):130–134, https://doi.org/10.5670/oceanog.2007.57.

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