| Home Page| Glossary                Search             Site Map | Français   |   Print  |      Plankton Plankton designates the tiny plant and animal species that drift in the water, carried about by the currents. Planktonic organisms that are part of the plant world are known as phytoplankton. In the estuary, they reach peak numbers between June and September. Those that are members of the animal world constitute zooplankton. These little organisms serve as food for many of the marine mammals frequenting park waters.