The Shackleton Transverse Ridge is a unique topographic barrier within the Drake Passage, strongly modulating circumpolar current dynamics and regional biogeochemical cycles in the Southern Ocean. Topographically induced current deflection, turbulent mixing, and sediment resuspension provide persistent iron sources that drive enhanced natural iron fertilization in this high‑nutrient, low‑iron system. Combined with in situ microbial activities, including microbial iron regeneration and organic matter remineralization, bioavailable iron inputs collectively alleviate ambient iron limitation, restructure plankton community composition, and elevate primary production. Shifts in plankton assemblages further alter food web structure, particle sinking rates, and vertical carbon transportation. These physical and biological coupling processes substantially regulate the magnitude, pathway and efficiency of carbon export from surface waters to the deep ocean. This perspective highlights that topographic hydrodynamic regulation and microbial modulation are two indispensable drivers sustaining active iron cycling, shaping plankton ecosystems, and strengthening biological carbon sequestration over the Shackleton Transverse Ridge.