GEOTHERMAL CONVECTION IN CONTINENTAL SHELVES: A SIGNIFICANT CONTRIBUTOR TO SEAWATER CHEMISTRY?
Results show multiple geothermal convection cells associated with seafloor topography, but the number of flow cells decreases with decreasing sediment permeability. Maximum fluid velocities of 0.1-0.5 m/yr develop near steep areas of the seafloor, particularly at the continental slope. For medium-grained carbonates, the total simulated volume of fluid discharge in a 1 meter-wide slice of the continental shelf is approximately 60 m 3/yr. Based on this result, the total discharge along the 320 km stretch of the coast between Cape Fear and the Savannah River could exceed 10 7 m 3/yr, roughly 3 orders of magnitude smaller than river discharge to the ocean. However, concentrations of rare earth elements and other chemical constituents are much higher in the altered seawater that discharges the continental shelf than in river water. Thus chemical transport through continental shelves could affect nutrient and chemical budgets in the ocean.