Photochemistry and the Sea-Surface Microlayer: Natural Processes and Potential as a Technique

Abstract

Oliver C. zafiriou Woods Hole oceanographic Institution Woods Hole, Massachusetts 02543 U.S.A. The largest effects of photochemical processes in the Top Boundary Layer probably involve reactions at the sea surface of species formed by atmospheric processes. The ozone influx is probably the largest and most significant one. Ozone reacts with dissolved iodide and with other unknown components. one consequence is the formation of volatile iodine species, perhaps in sufficient amounts to balance the atmospheric iodine budget. However, most of the ozone react ion products undergo other fates. These reactions drive chemical fluxes that may be coupled to other Top Boundary Layer processes in three ways: (1) modification of air-sea gas eXchange processes and fluxes, (2) chemical modification of trace components of the Top Boundary Layer, especially of species with long residence times there (indigenous biota, surface-active molecules, particles), and (3) chemical modification of the physical properties of the interface via reaction of surface active materials, leading to changes in surface physical properties. These mechanisms may link. the photochemically-driven fluxes to trace element fluxes, surface biology, the fate of particles at the interface, and the damping of capillary waves by surface tension effects.