U.S-Argentina Cooperative Research: Ozone-Related Impact of Solar Ultraviolet Radiation on the Marine Food Chain in Argentine Coastal Waters

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9503643 Holm-Hansen This U.S.-Argentina Cooperative Science Program award supports travel expenses and some expendable research supplies related to the visits of Drs. O. Holm- Hansen, E. Helbling and V. Villafane, Scripps Institute of Oceanography, La Jolla, CA to Ushuaia, Argentina. The objective of the research is to determine the impact of the UVR on sub-Antarctic plankton and to gain some insight into the possible ecological impact of enhanced UV-B radiation on these organisms. The Argentine counterpart is Dr. L. Orce, CIB, CONICET, Argentina Seasonal ozone concentrations in the stratosphere over Antarctica have been progressively decreasing during September-November of each year for the past decade, with the result that the fluence of the shorter UV-B wavelengths (280-320 nm) is greatly enhanced. The biological impact of this increased ultraviolet radiation (UVR) has been studied intensively in the Antarctic, but little work has been devoted to this problem at lower latitudes, such as the southern regions of South America. Although ozone depletion is greatest at very high latitudes, increased UVR may pose significant problems for plant and animal life in the southern regions of Argentina, due to the ozone hole actually extending over the South American continent, and also to the fact that low-ozone air flows from the Antarctic north over South America. The marine environment at Ushuaia represents a prime locality for studying the biological impact of increased UVR on the marine food chain leading up to harvestable marine resources. These cooperative UVR studies incorporate into one integrated field program the biochemical expertise provided by Dr. Orce and his colleagues in Argentina, with the oceanographic and experimental experience with UVR provided by the U.S. investigators. The studies are specifically designed to assess the effect of increased UVR on the viability and metabolism of marine phytoplankton, with emphasis being p laced on rates of primary production, which constitutes the base of the marine food web. The laboratory and field facilities for such studies are excellent at Ushuaia. An essential component of the work is the availability of recording UV- spectroradiometers and profiling spectroradiometers which can be lowered to a 100m depth, installed by Dr. Orce under an Interamerican Development Bank (IDB)-CONICET grant. ***