What are examples of ultra plankton?

Ultraplankton refers to planktonic organisms that are typically smaller than 2 micrometers, including various types of bacteria and phytoplankton. Examples include picoplankton such as Prochlorococcus and Synechococcus, which are important photosynthetic microorganisms in marine environments. Additionally, certain small flagellates and cyanobacteria also fall under the category of ultra plankton, playing a crucial role in aquatic food webs and carbon cycling.