Marine Biology

Phytoplankton

The free-floating plant plankton are called phytoplankton and wide range of photosynthetic organisms are included under this category.  Generally, phytoplankton are grouped under algae.  These are usually single celled (unicellular, filamentous, or chain forming species) that inhabit the euphotic zones / epipelagic zones of surface waters in open oceans and coastal environments. 

         The primary importance of these plants is due to their ability to capture the solar energy to make food.  Phytoplankton are the prime producers of oxygen and contribute a significant portion of the oxygen found in the air we breathe. They are the base of the food pyramid. Most aquatic organisms  of the higher trophic levels depend on these microscopic single-celled organisms for food and oxygen.  Without them, marine animals would die off and the atmosphere would lose a major source of oxygen. There are several types of phytoplankton viz.,  diatoms,  dinoflagellates, blue-green algae, etc.