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Youth Area Watch - Mussel Sampling/Pristane
Project
Youth Area Watch has been involved with
scientists working at Auke Bay Lab near Juneau,
Alaska for the past 3 years. Jeff Short and Pat
Harris are the principle investigators that
students work with. This study, known as the
pristane project, is designed to monitor the levels
of planktonic activity and production capacity in
Prince William Sound. This monitoring is
accomplished using a rather unique method. Mussels
from beaches around Prince William Sound are
analyzed to determine the level of a hydrocarbon,
called pristane, in the water column. Pristane is a
substance produced by two very important species of
copepod (zooplankton). These copepods are very
important in the food web of Prince William Sound.
By monitoring the level of pristane in the water
column, Jeff and Pat can make reasonable
predictions about the health and production
capacity of the Prince William Sound ecosystem.
Students help Jeff and Pat by collecting mussels
near their towns throughout the spring and
summer.
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Youth Area Watch students from around
the sound participate in a mussel sampling
project. In doing this project, all of the
students have to go down to the mussel bed
nearest to them and cut twenty mussels off
the rocks. They do this once every couple
of weeks depending on the tides.
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The cycle starts with the phytoplankton
absorbing sun, the source of their
existence. Then a carnivorous species
known as zooplankton eat the
phytoplankton. While the phytoplankton is
going through the copepod's (zooplankton)
digestive system, a chemical byproduct
known as pristane is created.
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Scientists have been graphing the
pristane levels in water all around the
sound for the last three years. As you can
see, in the months of April, May and June,
the pristane levels rise. This happens
because in those months the plankton bloom
is going on. More plankton means more
copepods and more copepods means more
pristane.
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These copepods are eaten by larger
predators such as herring and different
species of fish. The fish are eaten by
higher predators such as sea lions, seals
and other scavengers such as crabs.
Pristane is a substance that cannot be
digested or broken down. So, the predator
will have a small level of pristane in it
after eating fish that ate copepods. When
the predator leaves waste containing
pristane (the fish can leave waste
containing pristane also) filter feeders
such as mussels consume the waste. By now,
the pristane level is very low. There is
enough for scientists to examine the
mussels and find the amount of pristane,
though.
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Kids from different sites around Prince
William Sound help collect mussels. A few
selected students go to unpopulated sights
with Pat Harris to collect mussels. The
collected mussels are taken to Auke Bay
Lab in Juneau, Alaska to be examined for
their levels of pristane. Youth Area Watch
students get to travel to this lab in the
spring and learn how the mussels are
analyzed.
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