1. The Photobiological History of Earth, C. Cockell. Introduction, UV radiation from the Archean to the Archean-Proterozoic transition, Calculation of UV radiation on early Earth, Atmospheric absorbers and effects on Archean photobiology, Biological effects of high UV radiation flux, Methods for coping with UV flux on early Earth, Photosynthesis in the Archean, Beneficial effects of high UV radiation on Archean Earth, The Archean-Proterozoic transition, UV radiation in the Proterozoic and Phanerozoic, Conclusions. 2. Physical Factors Determining Ultraviolet Radiation Flux into Ecosystems, M. Xenopoulos & D. Schindler. Transmission of solar UV through the atmosphere to the Earth's surface,Transmission of solar UVR through water. 3. Ultraviolet Radiation and Amphibians, A. Blaustein, et. al. Introduction, Effects of UV-B in the field, Sublethal effects, Synergistic effects, Amphibian defences against UV-B radiation, DNA Repair, Ecological consequences of Ultraviolet damage to amphibians, Disturbances may exacerbate the effects of UV-B radiation, Conclusion. 4. Ultraviolet Radiation and Plant Ecosystems, T.A. Day. Introduction, UV-B Environment of Terrestrial Plants, Ozone depletion and enhanced UV-B, Approaches to studying plant responses to UV-B, Are plants responsive to current UV-B? Are plants responsive to enhanced UV-B levels? General Plant Responses, Response Mechanisms, What traits might confer tolerance or sensitivity to UV-B? Interactions with other trophic levels, Conclusion. 5. Ultraviolet Radiation and Coral Communities, D. Gleason. Introduction, Measurement and penetration of UV-R in reef waters, Physiological effects of UV-R on coral reef organisms, UV-R protective mechanisms in coral reef organisms, UV-R and distributional patterns of coral reef species. 6. Ultraviolet radiation and aquatic microbial ecosystems, D. Hader. Introduction, Measurement of UV radiation in the water column, Effects of solar UV radiation on dissolved organic material,Bacterio- and picoplankton, Cyanobacteria, Phytoplankton, Freshwater ecosystems, The Antarctic aquatic ecosystem, The Arctic aquatic ecosystem, Conclusions and Consequences. 7. Ultraviolet Radiation and the Antarctic Coastal Marine Ecosystem, M. Vernet & W. Kozlowski. Introduction, The Antarctic Coastal Marine Environment. 8. Ultraviolet Radiation and Exobiology, C. Cockell. Introduction, The ultraviolet history of Mars - An exercise in comparative evolutionary photobiology, The present martian UV flux - implications for human exploration and settlement, UV Radiation and extrasolar planets, The UV radiation environment of extrasolar planets, Conclusion. Index.