FREE-FLOATING DRIFTER FOR PHOTOCHEMICAL STUDIES IN THE WATER COLUMN

A free-floating drifter was designed to directly determine in situ pho tochemical production rates, photolysis rates, and light fluxes in sea water. This drifter consisted of six trays that were suspended in seri es from a single buoy line. The trays were constructed so that the att ached quartz vessels, containing filtered seawater, were exposed to bo th downwelling and upwelling irradiation. The quartz vessels were seal ed at both ends with ribbed TFE Teflon stoppers that permitted multipl e subsampling without introduction of a headspace. The free-floating d rifter was used to study photochemical processes in antarctic waters. It performed well during 12-15-h deployments, even in rough seas with sustained winds between 15 and 26 m s(-1). Although not tested here, t he drifter should perform equally well in the study of photochemical p rocesses in freshwater environments.