The deep basins of the Bransfield Strait (BS) are ventilated by Weddell Sea (WS) waters from different origins. Depending on the source and density, these water masses follow different routes across the complex topography near the tip of the Antarctic Peninsula and thus into the Bransfield Strait abyss. Using a global setup of the Finite Element Sea-ice Ocean Model (FESOM) we show that the WS waters found at the western WS continental shelf break have a higher influence on the short period variability of BS bottom waters than the waters present over the continental shelf. Adding passive tracers to the glacial melt water (GMW) from two different origins, Larsen Ice Shelf (LIS) and Filchner-Ronne Ice Shelf (FRIS), we show that the GMW from FRIS has a larger influence on BS bottom waters than the GMW from LIS. FRIS GMW has a higher concentration in the BS eastern basin, while LIS GMW is more abundant in the BS central basin. This duality mainly leads to the difference between BS central and eastern basins seen on the observations. This is a novel result and we believe is a significant contribution to the understanding of the BS-WS circulation and interactions.