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UV-B EFFECTS ON TERRESTRIAL ECOSYSTEMS
Citation:
Olszyk, D. UV-B EFFECTS ON TERRESTRIAL ECOSYSTEMS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-93/245 (NTIS PB94107984).
Description:
Dpeletion of stratospheric O3 layer should result in enhanced levels of ultraviolet-B (UV-B) radiation at the earth's surface compared to present, with potentially damaging effects on biological systems. his paper briefly summarizes some key findings for UV-B effects on terrestrial ecosystems, and describes an ecological risk assessment model applicable to the impacts of enhanced UV-B on those systems. otential use of the model is evaluated in terms of a project to determine the risk from UV-B on irrigated rice in southern and eastern Asia. reliminary results are presented from this cooperative project between the U.S.Environmental Protection Agency (EPA) laboratory in. orvallis, Oregon (ERL-C), and the International Rice Research Institute (IRRI) and their collaborators in other countries. n terms of scoping studies, phytotron studies at IRRI show growth reductions with enhanced UV-B radiation for many of the 188 cultivars tested. o characterize UV-B stress in rice producing areas, Corvallis scientists using atmospheric radiation transfer and general circulation model outputs and climate data, indicate that current UV-B exposures differ considerably across rice producing areas of Asia depending on latitude and growing season, and that global climate change could impact future UV-B exposures by modifying the amount of cloud cover. o characterize the direct effects of UV-B to rice yield, a large-scale field study is underway at IRRI under natural environmental and crop management conditions. reliminary results from the UV-B treatments show no direct effects on yield. owever, in terms of indirect effects of UV-B, preliminary results from IRRI and Washington State University suggest that UV-B can alter the susceptibility of rice plants to disease and affect the disease fungus itself.