bathythermograph (BT) winch,
was lowered rapidly to the desired depth,
towed at this depth for designated periods varying from 15 to 125 minutes,
and then raised rapidly to deck level.
Haul depths from the surface to
457 meters were determined by the use ofa BT.
The volume of the
sample was determined volumetrically by allowing the sample to settle
for five minutes in a graduate cylinder.
Details of the plankton hauls
are given in Appendix Table A.
In order to
direct the movement of the ship while attempting to
lineate the mass of radioactive water produced by the
de-
Wahoo detonation,
a 5-cc portion of plankton samples P-22 to P-35 was filtered through a
Millipore filter disc 47 mm in diameter (pore size 0.45u), and the
gamma
sample.
Island,
total
activity of the plankton was determined immediately on the wet
Later, at the Eniwetok Marine Biological Laboratory on
the
gross beta
activity of the sample
Parry
was determined on
the
dried material.
In some samples the plankton were separated into
"small" plankton.
"“large'' and
The sample was first filtered through a bronze
screen 2-3/4 inches in diameter with a mesh of 99 to the inch (large
plankton), and then through a
Millipore filter disc with a pore
size of
0.454 (small plankton).
For the determination of gross beta activity,a portion of each sample
was placed on a 1-1/2-inch stainless steel planchet, dried under infrared
lamps, and counted aboard ship.
The beta-counting equipment consisted