Exploratory Research On The Stability And Reactivity Of Higher Oxidation State Mn and Fe Complexes In Seawater Pyrite oxidation in salt marsh sediments and sulfide oxidation in the waters of the Black Sea and the Chesapeake Bay can occur by anaerobic processes. These processes are chemical at the electron transfer step, but can be mediated by biological processes. In salt marshes where dissolved Fe concentrations reach mM levels, pyrite oxidation can be mediated by Fe (III) organic complexes because of the rapid cycling of dissolved Fe. The main reactions of the iron cycle are (1) solubilization of Fe(III) by organic ligands, (2) reduction of soluble Fe(III) to Fe(II) by these ligands, soluble reduced sulfur or pyrite, (3) the oxidation of the resulting Fe(II) (complexed to organic chelates) by Fe(III) minerals releasing more dissolved Fe(III), and (4) the formation of iron sulfide minerals when dissolved sulfide is in excess. This cycle of iron solubilization will continue as long as bacteria and/or plants produce organic ligands. This study will investigate the reaction of sulfide with soluble Fe(III) and Mn(III) complexes and develop a method for the determination of dissolved Mn(III) in anoxic waters. These complexes should exist even as catalytic intermediates in organic rich anoxic waters. They are easily prepared based on methods in the chemical literature. //
