Copepods are major consumers of phytoplankton.
Zooplankton
Zooplankton make up the animal component of the plankton
community. With only a few exceptions,
they are tiny creatures, many of whom are barely visible to the
naked eye.
Some of the zooplankton in Greenwich Bay are planktonic their
whole lives, and are called holoplankton.
Others are merely plankton for the first part of their lives, and
these are called meroplankton. Can you guess some of the
familiar animals that spend part of their lives as plankton?
Click to see some of them.
Half to three-fourths of the zooplankton in the Bay are tiny
crustaceans called copepods.
Copepods are major consumers of phytoplankton.
The eggs and larvae of nearly all fish and benthic (bottom-dwelling) animals are part of the plankton community. Some common examples are:
Many zooplankton (zoo = animal, plankton = drifter) are tiny,
larval stages of familiar animals such as fish, clams, and crabs.
(graphic) These part-time plankton are known as meroplankton.
They begin as eggs, then move through one or more developmental
(or larval) stages before they take their final adult forms.
Often, the planktonic stages look completely different from the
animals we know in their adult forms, for example:
Barnacle:
egg - nauplius - cyprid - adult
Others, such as copepods, (graphic) remain plankton their
entire lives. In Narragansett Bay, copepods make up half to
three-quarters of the zooplankton. Holoplankton are animals that
spend their entire lives as plankton.
One common member of the plankton community is surprisingly
different from the others. Since plankton are defined as
organisms that float and drift with winds and currents (many
plankton are able to swim, but they are not strong enough to set
their own course against the direction of these winds and
currents), jellyfish and their familiar relatives, comb jellies,
or ctenopohores, are also considered plankton .
