aa, Daas At present the activity in the lower levels differs Theresulting gamma activi- little from that of the upper. ties forthe deep fishes are therefore, very simliev ¢ those for plani:ton of the upper laycrs. %~ should be noted that the foregoing study was made within the influence of the Bikini Eddy System and may be representative of that eroa only. 265 RADIOACTIVITY EACKGROUND OF THE CCEAN PLOOK A series of 16 samples cf the ocean Floor were tekken a around Bikini Atoll. These were obtained with a coving and & bottom dredges. 3 wet They consisteé of small bits «f ccral, baselt, mongenese nolules, coarse ccral sand and fhre gioblgerina core (fossils of minete organisms of ths order §? Portions of such material were velshel, dried , Foraminifera). et 130° GC. in elurcinum planchets, and counted for gauma radioactivity. Several of the cores were lost dus te the inability or the core barrel to peuetrate, anz the core-cetcier to pe- was also countec and was found than th:¢ water. to be considerably mere eative The top laver of each core, end portions of the dredge samples were assayed. Yhe results are skown in igure 2. in which the activity of the gamma radiation er "3 * od - —~ s devire greu of ccean flcor surface is viotted at locations semplec.- In general, the most radioactive samples consisted of globS cue Zire ooze (Fig. Z.core Ca2, C(t, Ce104). ~ Manganese nodules QB,