[en] Vertical eddy diffusivities (Ksub(V)'s) have been estimated at fourteen widely separated locations from fourteen ²²²Rn profiles and two ²²⁸Ra profiles measured near the ocean floor as part of the Atlantic and Pacific GEOSECS programs. They show an inverse proportionality to the local buoyancy gradient calculated from hydrographic measurements. The negative of the constant of proportionality is the buoyancy flux which has a mean of -4 X 10^-6 cm²/sec³. The results suggest that the buoyancy flux varies very little near the ocean floor. Ksub(V)'s for the interior of the deep Pacific calculated from the relationship Ksub(V) = (4 X 10^-6 cm²/sec³)/[(g/rho)(deltarhosub(pot)/deltaz)] agree well with published estimates. Ksub(V)'s calculated for the pycnocline are one to two orders of magnitude smaller than upper limits estimated from tritium and ⁷Be distributions. Heat fluxes calculated with the model Ksub(V)'s obtained from the ²²²Rn profiles average 31 μcal cm^-2 sec^-1 in the Atlantic Ocean and 8 μcal cm^-2 sec^-1 in the Pacific Ocean. (Auth.)