Particulate transport of radionuclides 14C and 55Fe to deep waters in the Pacific Ocean

Observations during 1969 to 1971 indicate that radionuclides /sup 14/C and /sup 55/Fe in particulates in Pacific Ocean water 28 to 31/sup 0/N, 119 to 121/sup 0/W up to depths of 2,500 m were transported from the surface within a short time (<10 yr). The mean downward sinking rates for /sup 55/Fe and /sup 14/C are deduced to be 0.5 x 10/sup -3/ and 2.5 x 10/sup -3/ cm s/sup -1/. The appreciably faster transport of /sup 14/C is consistent with the fact that the mean size calculated for biogenic calcareous particles transporting /sup 14/C is larger than that for the /sup 55/Fe-labeled particles.