Submarine groundwater discharge (SGD) delivers freshwater and nutrients into the ocean from the seafloor; however, the fate of these inputs remains insufficiently understood. Using a non-hydrostatic ocean circulation model (MITgcm) with grid resolutions of 4–5 meters, we investigated the dynamics of a buoyant freshwater SGD plume and its associated nutrient transport in an idealized deep coastal domain. A control run and sensitivity experiments were conducted by varying SGD rate, latitude, ambient stratification, vent size, and model depth. The simulated freshwater input forms a buoyant plume above the vent and generates vertically stacked eddies with alternating rotation directions. Advective flux by the rising plume dominates vertical nutrient transport, whereas diffusion plays a minor role. Tracer separation shows that the rising plume transports not only SGD-derived nutrients but also nutrients entrained from ambient bottom water, indicating that SGD can act both as a direct nutrient source and as a buoyancy-driven pump for pre-existing bottom nutrients. Plume structure and nutrient redistribution depend strongly on environmental and source conditions. Weak rotation and weak stratification favor more direct upward transport to shallower layers, whereas stronger rotation and stronger stratification promote lateral spreading or confinement at depth. A larger vent area weakens the focused vertical jet but enhances horizontal redistribution and bottom-water entrainment. Shallower water columns allow the SGD signal to reach upper layers more easily, although entrainment of ambient bottom nutrients is reduced.

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