About Puget
Sound and Plankton Movement
Puget Sound and adjoining waters
to the north are located on the Pacific northwest coast of North America between
the Cascade and Olympic mountains. Within this area are many islands that have
small channels of water running between them. This water movement can affect
the vertical mixing of the water. In some channels the currents are very fast
and turbulent, which leads to thoroughly mixed water. In bays, on the other
hand, there is little mixing of the water layers. There are two unequal pairs
of tides per day in Puget Sound, and the lower of the low tides usually succeeds
the lower of the high tides. The difference in water level between low and high
tides in a given day is from 0.9 m to +3 m, with these extremes usually occurring
during May and June.
Animals that make up the plankton
typically migrate vertically on the order of 400 to 1,000 meters per day. The
plankton is found deep in the water during the day and toward the surface at
night. Factors that influence this migration behavior are thought to be:
grazing plankton can feed
more effectively on phytoplankton, which are near the surface for photosynthesis;
plankton can escape from visually-oriented
predators that are near the surface during the day;
planktonic animals can decrease
their metabolic activity when they are in deeper and colder waters;
planktonic animals may have
better geographic dispersal through deep water movement.
Plankton
Home Annelida
Arthropoda
Chaetognatha
Chordata
Cnidaria & Ctenophora
Echinodermata
Mollusca
Invertebrates
2000