It seems that you have the eye for microscopic organisms, it is impressive. They are cool right ?
About them
Microorganisms arn't a taxonomic group, indeed it's a biological group that gather by size all microscopic (~10-6m) organisms. They exists in all phyla of life, i.e. Bacteria, Archaea and Eukaryota. The two first are in fact composed only of microoganisms whereas Eukaryota include larger organisms like us humans.
Regardless of their small size microorganisms constitute the highest biomass in oceans (M. Bar-On & Milo, 2019). Their largest contributors are Eukaryota protists, like dinoflagellates and diatoms I work currently on during my PhD.
Examples
Some IFCB images of protists found in the Penzé estuary in summer 2026 :
