Processes controlling the distribution and cycling of dissolved manganese in the northern South China Sea

Abstract The Northern South China Sea (NSCS) is one of the most important marginal seas in the northwest Pacific Ocean. It receives large amounts of terrestrial inputs, and is affected by intrusion of Kuroshio Water. Dissolved manganese (Mn) can be used as a chemical tracer, facilitating study of fluxes and processes at ocean interfaces. To investigate the behavior and transport of dissolved Mn in the NSCS, we measured the concentrations of dissolved Mn in samples collected in summer 2011 and 2015, during field survey voyages supported by the National Science Foundation of China. The concentration of dissolved Mn ranged from 0.5 to 29.9 nM, with an average of 3.7 nM. Elevated concentrations (>15 nM) of dissolved Mn were found in coastal waters, while low concentrations ( 60% of the material transport flux occurring in the Luzon Strait.