A nonlinear inverse method is applied to nutrient data upon approximately 20 neutral surfaces in each of the South Atlantic, Indian, and Pacific basins, between 400 and 4000 m depth. By accounting for the gradients in nutrients due to the mixing of ''preformed'' concentrations of the major water masses, the nutrient changes due to biological activity are examined, and the time-mean, basin-wide Redfield ratios calculated. It is found that the P/N/Corg/-O2 ratios of nutrient regeneration between 400 and 4000 m (corrected for the effect of denitrification) are approximately constant with depth and basin, at a value of 1/16¿1/117¿14/170¿10. These ratios agree with those of fresh organic matter, suggesting that the flux of organic material to the deep ocean may be dominated by fast-sinking matter produced by sporadic, high-productivity events. Sedimentary denitrification reduces the N/P utilization ratio to 12¿2 between 1000 and 3000 m. In the Indian and Pacific basins the Corg/Cinorg regeneration ratio decreases from approximately 7¿3 at 400 m to 3¿1 at 1000 m and to 1¿0.5 at 4000 m, suggesting a significant amount of calcium carbonate dissolution above the calcite lysoclines in the Indian and Pacific oceans.