I. OBJECTIVES OF SEAREX | The Sea/Air Exchange (SEAREX) Program is a multi-institional program funded by the National Science Foundation, Office for the International Decade of Ocean Exploration. 1. The objectives of the overall] program are threefold: The quantitative measurement of atmospher ig fluxes of selected heavy metals (e.g., Pb, Cd, Zn, Se, Sb, As, Cu, Hg, Ag), ¢!9Pb and its daughter Po and organic compounds such as the man-associated PCB, DDT, polynuclear aromatic and aliphatic hydrocarbons, phthalate plasticizers and the natural occurring steroidal and terpenoid hydrocarbons, fatty acids and alcohols, low molecular weight compounds such as ketones, aldehydes, and carboxylic acids to the ocean surface. 2. The identification of the sources for these substances in the marine atmosphere. 3. The investigation of mechanisms of exchange of these substances across the sea/air interface. To atain these objectives a program of 5-6 years duration is expected. Major components of the program include: 1. Estimation, from rain and dry deposition measurements, of the flux of heavy metals and organic substances during the wet and dry seasons at Mid-Pacific sites in the North and South Pacific Ocean. These sites will be at Enewetak Atoll in the North Pacific trades and at Tutuila Island, American Samoa in the South Pacific trades. 2. Investigation of the importance of the ocean as a source for atmospheric heavy metals and organic substances through enrichment and fractionation effects occurring during the production of atmospheric sea salt particles by bursting bubbles. These studies will be undertaken using the Bubble Interfacial Microlayer Sampler (BIMS) developed at the University of Rhode Island together with an assessment of the natural occurrence of bubbles under varying conditions. 3. Evaluation of the significance of soil and vegetation emissions, forest fires, and chemical manufacturing sites as sources of the volatile metals and organic substances found in the marine atmosphere. 4. Identification of tne natural or anthropogenic origin of Pb in marine aerosols by means of Pb isotope tracers and mass balance relationships of present atmospheric input fluxes with prehistoric sediment output fluxes. 5. Investigation, using classical as well as sophisticated laser fluorescence techniques, of the distribution and exchange between the particulate and vapor phase of organics and of the relatively volatile heavy metals such as Pb, Cd, Zn, Se, Sb, As, Cu, Hg, and Ag. 6. Investigation of bubble surface area and volume spectra in the sea and the relative importance of single bubbles and bubble rafts as sources of atmospheric spray and sea salt particles, both as a function of wind speed.