Importance of phytoplankton  The food web  Phytoplankton are the
foundation of the aquatic food web, the primary producers,
feeding everything from microscopic, animal-like zooplankton to
multi-ton whales. Small fish and invertebrates also graze on the
plant-like organisms, and then those smaller animals are eaten
by bigger ones.  Phytoplankton can also be the harbingers of
death or disease. Certain species of phytoplankton produce
powerful biotoxins, making them responsible for so-called “red
tides,” or harmful algal blooms. These toxic blooms can kill
marine life and people who eat contaminated seafood.  Photograph
of fish killed by a red tide on the shore of Padres Island,
Texas.  Dead fish washed onto a beach at Padre Island, Texas, in
October 2009, following a red tide (harmful algal bloom).
(Photograph ©2009 qnr-away for a while.)   Climate and the
Carbon Cycle   Diagram of carbon fluxes in the upper ocean.
Phytoplankton are responsible for most of the transfer of carbon
dioxide from the atmosphere to