Disintegration rates (d/m/s) of the radioisotopes separated from five plankton samples on te) date of analysis (July 1957) and (B) corrected to date of collection (September 1256). I Isotope II Plankton Plankton _(7,8,9) A ° (13,14,15) B Rut%%_Rnl%G 3,100 1,930 Zr95-Nb?> 266 6,800 Celtteppl44 g07 «1,275 3789-90 0 ¢3i37 Mn>4 O 0 B 3 3 522 13,490 * * 0 0 20 0 trace Fe>> Feo? Col 4,360 5,300 0 0 1,240 2,720 4,880 0 1,180 5,860 0 2,600 600° 2,182 203 231 zn©5 2,100 4,900 1,830 10 242 4,100 * Not determined 249 3! 0 re ~~ i Q Z/ A 9 trace C038 0 III a Zz Yn 249 4,200 4,200 IV Plankton (43, 44,45,46) A B 0 0 460 11,800 5,940 12,500 0 136 137 0 139 274 10,000 12,000 0 0 6,700 14,700 1,450 24,500 1,090 1,240 7,120 16,400 Vv Plankton (50,51,52,53) A B 0 0 350 8,960 2,500 5,250 oO 229 109 A 0 . 234 218 421 7,110 522 9,200 21,200 B 82 0 2,100 51 0. 102 O 15,100 18,100 0. 0 1,822 4,000 458 Plankton (57, 58,59) * 11,900 0 628 14,300 0 1,700 312 356 125 2,110 7,050 16,200 -cT- Table 2.