Plankton
Plankton is the name given to all the microorganisms that float on the sea. The name comes from the Greek language term for "wanderer" or "drifter".
Plankton are divided in two classes: phytoplankton and zooplankton:
- Phytoplankton (phyto: vegetal) are small algae and fungi. They obtain energy by photosynthesis, and live mostly on the upper part of the sea, because they need light to survive.
- Zooplankton (zoo: animal) are small protozoa, crustaceans, krill, etc. and the eggs and larvae from larger animals.
Plankton concentration and distribution is very sensitive to chemical and physical changes in the sea water.
hyperiid amphipod Hyperia macrocephala (copyright Uwe Kils)
See also: algal bloom, domoic acid