Cell division
"Richelia intracellularis" is also found in "Rhizosolenia" spp., a diatom found in oligotrophic oceans. Compared to the "Hemaiulus" host, the endosymbiosis with "Rhizosolenia" is much more consistent, and "Richelia intracellularis" is generally found in "Rhizosolenia". There are some asymbiotic (occurs without an endosymbiont) Rhizosolenia, however there appears to be mechanisms limiting growth of these organisms in low nutrient conditions. Cell division for both the diatom host and cyanobacterial symbiont can be uncoupled and mechanisms for passing bacterial symbionts to daughter cells during cell division are still relatively unknown.