Monterey Bay Aquarium Research Institute
Marine Botany



Peridinium sp. with its girdle clearly visible circling the cell median.  

Dinoflagellates (Phylum Pyrrophyta = Dinophyta) are perhaps the most charismatic of the phytoplankton.  Not only are they beautiful to look at under the scope, they also have the most diverse types of life histories, ecological niches and unique adaptations of all the phytoplankton.  They have two flagellae (which is their namesake), one that stays close to the median (pictured above) and one that trails the cell like a rudder.  Although Dinoflagellates are grouped with the phytoplankton, some species are unable to photosynthesize and instead are heterotrophic - able to directly ingest food.  Because they are fairly large cells, they are easily visible in plankton samples and if the samples are fresh, you can even observe their characteristic spinning movement.  Like other phytoplankton, Dinoflagellates go through bloom cycles when they are highly abundant and these blooms can be toxic (commonly called red tides), or bioluminescent.  


Class projects on Dinoflagellates:

Dinoflagellate QuickFacts:

Cell size: 20-200 m m

Cell wall: many materials (depends on species), including cellulose; some even lack a cell wall

Chloroplasts: many/cell, 2-5 thylakoid membranes/stack

Photo-pigments: chlorophyll a & c, carotenoids; some unpigmented

Reproduction: simple cell division, rarely sexual reproduction 

Ecological roles: very diverse ecological roles, biflagellated, produce toxic blooms & bioluminescence

Common generaNoctiluca, Gymnodinium, Gonyaulax, Pfiestra

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