Microbial food webs function much like chemostat
cultures and are more stable than the diatom-based food
webs. For example, in oligotrophic gyres, the abundance of
typical picoplankton species, such as Prochlorococcus,
varies within a 2-fold range throughout the year. Since cells
divide up to once a day, this stability is most likely due to
very tight control by microzooplankton.