DNARY
2.4
Pe)
RADIOBIOLOGICAL ASSAY OF NEAR~SURFACE 4ND DEEP SHA FAUNA
In general, the following 1s based on samples of Z00These
*
plankton -taken during the M, V. HORISON's cruise.
samples were collected with e standard one meter diameter
planktonnet towing obliguely from 280 meters depth to the
surface in 15 minutes time while the vessel proceeded at sbout
2 knots.
the inch.
inch,
The net mesh is of nylon "Nitex" cloth, 60 meshes to
Its cod-end is of the same material, A) mesnes per
The net is designed to sample 211 forns larger the
phytoplankton and crustacean larvae.
Samples were assayed for radioactivity without sarting
into like kinds of organisus.
"sanple" was small crustaceans,
In most cases the bulk of the
Large, individual enimals
were removed for individuel assay.
of the radiological assay.
Table 2 lists the resuits
Station positicns are given in
Figs. 1A, 13.
is significant that the greater activity is to be found within
4
the influence of the eddy system around Bikini, Ailinginae
and Ronesisr
Atolis (Figs. 64 to 68).
It is probable that
within this area the supply cf radioactivity in the ccean is
being constantly renewed by tidal flow from Bikini and neighber~
ing atolls to the east.
Swept into the eddy where it does not
escape for some extended period of time crop after crop of the
short lived plankton become ccntaminated.
18
As will be shown
IY
Se