Manganese in Narragansett Bay

Concentrations of dissolved manganese and particulate manganese and aluminum were determined in samples from Narragansett Bay, Rhode Island, and its surrounding rivers. Total manganese is approximately conservative, but dissolved and particulate manganese are not. Desorption may occur in the tidal rivers at low salinities. Most riverine manganese is dissolved but manganese in the bay is predominantly particulate, probably due to rapid manganese oxidation at bay water pH. The flux of dissolved manganese into bottom waters was about 2 ± 1 μ g cm-2 d-1. Concentrations in bottom waters are high relative to surface waters.