MILLERO 9400784 This project will continue the study of how ionic interactions affect processes in seawater and other natural waters. In the next two years efforts will be directed at how ionic interactions affect the rates of oxidation and reduction of metals and nonmetals in seawater. Measurements of the rates will be made in seawater as a function of pH, salinity, temperature and composition to elucidate the effect of the ionic components of seawater. Studies of the products and intermediates of the reactions will be made (when possible) in an attempt to elucidate the mechanisms of the actions. During the next two years it is also planned to continue measurements on oxidation of H2S with the oxides of Fe(II) in seawater. The measurements will be made as a function of pH, temperature, and salinity. The disappearance of H2S and the appearance of Fe(II) will be measured. It is also planned to determine how the products S, SO3 2-, and S2O3 2- are affected by pH, temperature, and salinity. Studies will also be initiated on the reduction of Fe(III) with H2S03 and the oxidation of Fe(II) with O2 at nM levels in natural waters. New thermodynamic modeling will be carried out on the carbonate system and the state of Fe(II) and Fe(III) in seawater. These studies will hopefully lead to a consistent set of stability constants and Pitzer interaction parameters that can be used to characterize these systems in natural waters.
