Aquatic ecology and Biodiversity

Unit 7- Biotic communities

7.1.4. Functional groups of plankton
There are two types of plankton - phytoplankton and zooplankton. The word phyto comes from the greek word meaning 'plant' and plankton translates to 'drifter.' These tiny organisms are plants that drift throughout the world’s oceans.

Planktonic organisms

Phytoplankton (phyton, or plant), autotrophic, prokaryotic or eukaryotic algae that live near the water surface where there is sufficient light to support photosynthesis. Among the more important groups are the diatoms, cyanobacteria, dinoflagellates and coccolithophores, silicoflagillates, green algae, blue green algae etc.
Zooplankton (zoon or animal), small protozoans or metazoans (e.g. crustaceans and other animals) that feed on other plankton and telonemia. Some of the eggs and larvae of larger animals, such as fish, crustaceans, and annelids are also included.
Bacterioplankton, bacteria and archaea, which play an important role in remineralising organic material down the water column (note that the prokaryotic phytoplankton are also bacterioplankton).