Zooplankton are small creatures are most commly found in the littoral
zone ocean, but they can also be found in bodies of fresh or brackish
water. Their name comes from the Greek word "planktos"
meaning drifter, as they are subject to
the turbidity of the water and have very little control over their own
mobility (though looking at them under a microscope can be quite
difficult if they are not fixed). Zooplankton are made up
of subdivision of plankton
that are cateogorized into two categories; those who are in a
developmental stage and will one day no longer be plankton, and those
who are plankton throughout their entire lives due to their size.
One defining characteristic of
zooplankton is the fact they they sink
down to the ocean floor during the day and rise up to the littoral zone
at night. This is a defense mechanism against predation.
During the day, it is better to remain low and out of sight, but
corals feed in the evening making it beneficial to float to the
surface at night.|