Monterey Bay Aquarium Research Institute
Marine Botany

DinoflagellateHabitat, Ecology, and Behavior

Dinoflagellate Factories: The Dino Life History

life history diagram

Dinoflagellates undergo a somewhat complex life cycle. Under normal circumstances they reproduces just like any cell, by asexual division -- new dinos pinch off from old ones. But under certain conditions, usually stressful ones like cold, starvation, no light, etc., they will do something different. Two dinoflagellates will join together (called fusion). This stage is the planozygote stage. Then they change, sometimes quite dramatically, in shape and size. They get much bigger and they harden their shell (sometimes forming the spikes in the drawing.) Their insides change too, adding a lot of fat and oil, not unlike a bear getting ready to hibernate. In fact, dinoflagellates often seem to "hibernate" for the winter. When they are all done changing, the new, fat dinoflagellate is called a cyst or a hypnozygote. Then when the weather warms up, the cyst breaks out of its shell, forming a temporary stage called the planomeiocyte (not present in all species). This stage quickly reforms its shell (remember the theca?) and becomes a normal dinoflagellate again.

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Copyright Josh Rapport 1996

Last updated: Feb. 05, 2009