Action Outdoors
Educational Resources for Teachers and Schools

Phytoplankton
(Coulombe, 1992)

• Phytoplankton is made up of unicellular plants; diatoms and dinoflagellates.
• They are important producers.
• They form the base of the food chain.
• Phytoplankton changes inorganic nutrients into oxygen by way of photosynthesis.
• “It is estimated that 75-85 percent of the oxygen on earth are produced by phytoplankton.”(Coulombe, 1992)

Diatoms (“cut in two”)

• Single celled yellow-green algae that produce much of the world’s oxygen.
  
• Diatoms contain a silica shell, which is a glass like substance. The shell does not act as a tight container but overlaps. An easy way to remember this is that a diatom shells fits like a lid fits on a box.
  
• “Diatoms are well adapted to floating and probably the single most important food source in the ocean” (Coulombe, 1992).
  

• These organisms can photosynthesis like plant plankton and swim like simple animals. Dinoflagellates propel themselves through the ocean by using two flagella.
  
• “Red Tide” is caused by the Dinoflagellates “Gonyaulax” and “Gymnodinium” . These phytoplankton are responsible for releasing toxins into the water and causing major fish kills, shellfish poisoning and respiratory disorders in humans.