Marine dissolved inorganic carbon (DIC total ) is a key component of the global ocean carbon cycle. Over recent decades, DIC total has increased due to rising anthropogenic CO 2 , but the response from the biological carbon pump (BCP), which transfers carbon from the surface to the ocean interior, remains uncertain. Here, we reconstruct global three-dimensional DIC changes from 2004 to 2024 down to 2 km depth and distinguish contributions from anthropogenic, organic matter remineralization, and calcium carbonate cycling. We find that while DIC total increased throughout the water column, driven primarily by anthropogenic CO 2 , the global inventory of biologically respired carbon associated with the BCP remained constant. However, this apparent stability masked pronounced regional and vertical redistribution of respired carbon within the ocean interior. In some regions, respired carbon accumulated at shallower depths, reducing its isolation from the atmosphere, whereas in others it was transported deeper, enhancing long-term storage. These contrasting patterns co-vary with changes in ocean stratification and ventilation, indicating that these processes regulate where biologically respired carbon is retained. Although these redistributions did not impact the net global carbon inventory over the study period, they reveal a structural reorganization of the BCP that may influence the ocean’s capacity to sequester carbon under continued climate change.