Studies will be conducted of ionic interactions and their effect on rate processes in seawater and other natural waters. 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 product and intermediates of the reactions will be made (when possible) in an attempt to elucidate the mechanisms of the reactions. Measurements will be continued on the oxidation of H2S and H2SO3 with O2 in seawater. The H2S studies will include: 1) measurements to examine how the products SO32- are affected by pH, temperature, and salinity; 2) measurements to determine hoe Fe (II), Fe(II) and Mn(II) affect the rates at nM levels of H2S. The H2SO3 studies will be made in seawater as a function of pH, temperature, salinity and the concentration of trace metals. Studies on the reduction of Cu(II) with H2O2 in natural waters will be completed and new measurements on the rates of oxidation of H2S with oxides of Fe(III) and Mn(IV) will be made as a function of pH, salinity and temperature. Measurements of the stability constants of metals with HS- will also be determined using a square wave polarographic technique. Field studies during the next two years will be located in the Cariaco Trench (Spring 1990) and the Chesapeake Bay (Summer 1990).
