Owing to both bioavailability and particle-reactivity, seawater dissolved Cu (DCu) profiles typically exhibit a nutrient-scavenging hybrid pattern, with concentrations generally increasing linearly with depth. Although various particles are likely to influence DCu distributions, the distinct role of individual particle types remains poorly constrained. In this study, samples for DCu and total dissolvable particulate Cu (TDPCu) from Niskin bottles, as well as PCu from in-situ pumps, were collected during a summer cruise to the subtropical western North Pacific (GEOTRACES-GPpr15). Concentrations of DCu generally increased with depth throughout the water column, yet substantial removal was observed in near-bottom waters at over half of the stations. By combining these observations with a modified one-dimensional reversible particle scavenging model, the increasing distribution pattern of DCu in the intermediate and deep waters is largely attributed to organic matter remineralization and desorption from biogenic particles. However, in the near-bottom waters, the DCu decline is most likely explained by removal from the dissolved phase via colloid-mediated processes, rather than reversible scavenging. This is supported by the elevated concentrations of small-sized TDPCu, as well as by the successful application of a colloidal pumping model, highlighting the previously overlooked role of colloids in bottom seawater trace element cycling.