Plankton - Aquatic Ecosystem

This group includes both microscopic plants (phytoplankton) and animals (zooplankton) found in all aquatic ecosystems, except certain swift moving waters. The locomotory power of the planktons is limited so that their distribution is controlled, largely, by currents in the aquatic ecosystems. Planktons are divisible into:

1. Plants (chiefly algae) known as phytoplankton; and
2. Animals (primarily crustaceans and protozoans) known as zooplankton. Most phytoplanktons and zooplanktons are capable, however, of at least some movement. Certain zooplanktons are extremely active and move relatively large distances, considering their small size, but they are so small that their range is still largely controlled by currents.