Monterey Bay Aquarium Research Institute
Marine Botany

Phytoplankton Blooms & Red Tides

Once in a while the water turns red with dinoflagellates. The population suddenly explodes and dinoflagellates fill the water so thick that no light can get through! This is called a red tide. Diatoms can also bloom. If the species of dinoflagellate or diatom that blooms happens to be poisonous, the effects can be drastic!

Phytoplankton blooms occur all over the world, from the Arctic to the Carribean. Red tides can devastate the fishing industry, and have prompted worldwide monitoring programs.


Only sixty out of 2000 species of described dinoflagellates are toxic. But the toxins in some of them are extremely potent. Strong enough to kill a man in less than one hour. The toxins are concentrated by mussels and other shellfish and then eaten by birds, fish, and man. Toxin monitoring programs and shellfish quarantines are in effect all over the world

Main  Dino Index

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Copyright Josh Rapport 1996

Last updated: Feb. 05, 2009