Dinoflagellates (Ceratium hirundinella)
The dinoflagella are a large group of flagellate protists. Most are marine plankton, but they are
common in fresh water habitats as well; their populations are distributed depending on
temperature, salinity, or depth. About half of all dinoflagellates are photosynthetic, and these
make up the largest group of eukaryotic algae aside from the diatoms. Being primary
producers make them an important part of the aquatic food chain. Some species, called
zooxanthellae, are endosymbionts of marine animals and protozoa, and play an important part
in the biology of coral reefs. Other dinoflagellates are colorless predators on other protozoa,
and a few forms are parasitic (see for example Oodinium, Pfiesteria).
