vert 12] faster rate of decrease in the radionuclide concentrations in sediments (v.s. the water column) the high ratio (4.14) found at Station B-20 cannot be so explained with the existing data, indicating either that regions of much higher concentration exist upstream, or that this area itself is a significant source of suspended sediments. The remarkable constancy of the particulate/ sediment radionuclide ratios demand further explanation in themselves. The process of suspension, deposition and redistribution of fine sediments at Bikini Atoll may be a dominant biogeochemical process to be understood in the redistribution of transuranium radionuclides in the Bikini Lagoon ecosystem. Both sampling designed to understand this process and thorough treatments of the water collection data should result in significant contributions to the study of marine biogeochemistry and the behavior of transuranic radionculides in environmental conditions.