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