 Phytoplankton are categorized into cyanobacteria (also called blue-green algae/bacteria), various types of algae (red, green, brown, and yellow-green), diatoms, dinoflagellates, euglenoids, coccolithophorids, cryptomonads, chrysophytes, chlorophytes, prasinophytes, and silicoflagellates.Zooplankton tend to be somewhat larger, and not all are microscopic.Many Protozoa are zooplankton, including dinoflagellates, zooflagellates, foraminiferans, and radiolarians.