Radiocarbon age structures of nine sediment cores from the tropical Atlantic Ocean show the effects of a depth-dependent relationship between dissolution and bioturbation. The age of the mixed layer becomes younger in cores taken from greater than 4400 m water depth. Solution-induced modification of the carbonate sediment, as indicated by weight percent fragmentation and percent resistant planktonic foraminifera, coincides with the change in age structure. The interaction of bioturbation with dissolution in sublysocline cores produces a bias in the observed radiocarbon age of the mixed layer towards young ages. Published observations of mixed layer ages in the equatorial Pacific show the reverse trend; mixed layer ages become older below the lysocline. The existence of Atlantic vs Pacific response patterns indicates that the bioturbation/dissolution relationship is environment-dependent and time-varying. This conclusion has two important implications for the interpretation of deep-sea sediment records: (1) 14C stratigraphies from different preservational settings cannot be strictly compared and (2) the steady-state solution of bioturbation models cannot be used as a tool for reconstructing the exact temporal history of a bioturbated record.