Diagenetic processes near the sediment- water interface of Long Island Sound. II. Fe and Mn.

The production of Mn²⁺ in pore water is directly related to the rate of reduction of Mn oxides during the decomposition of organic matter. Fe²⁺ on the other hand, is produced both by the reduction of Fe oxides and by abiogenic or biogenic oxidation of Fe sulfides. The result of different sources for the 2 dissolved metals is a different seasonality of the interstitial water profiles near the sediment water interface. Overall Mn²⁺ production mimics the seasonal and, to a lesser extent, the depth-dependent production patterns of metabolites such as NH₄⁺ (part 1). Fe²⁺ is also formed in abundance near the sediment - water interface during the early summer when the overlying water first begins to warm.-after Author