Ecosystems, Evolution, and Ultraviolet Radiation

ISBN-13: 9780387988788 / Angielski / Twarda / 2001 / 222 str.

C. Cockell; A. R. Blaustein; Charles Cockell

Opis

This book discusses UV radiation, its effects on ecosystems and the likely evolutionary consequences of changed UV radiation environments, past, present and future. The first two chapters examine the history of the UV radiation climate of earth and the factors that determine organismal and ecosystem exposure. Their purpose is to give the reader a physical perspective on UV radiation and an understanding of the constantly changing UV environment that ecosystems are exposed to over time. Variations in the UV radiation environment occur at the local level (such as boundary layer and plant canopy effects) through to global-scale changes (such as alterations in the column abundance of UV-B protecting ozone). UV radiation regimes also vary over temporal scales. These alterations occur on time scales of seconds (the movement of clouds and plant canopies) to literally billions of years (gross long-term changes in the composition of the Earth's atmosphere). In the chapters that follow five specific biological and ecological topics in photobiology are considered. They are effects of UV radiation on amphibians, plants, corals, aquatic microbial ecosystems and Antarctic ecosystems that are exposed to the anthropogenically generated ozone 'hole'. These chapters consider UV radiation effects at a diversity of levels from the biochemical to the community. Their purpose is to provide the reader with our current understanding of the ecological effects of UV radiation, the areas where questions still remain and to provide a perspective from which the reader can better understand questions in evolutionary photobiology. The final chapter investigates the biological consequences of altered extraterrestrial ultraviolet fluxes, which are quite different from those experienced on the Earth. Our knowledge of the role of UV radiation in shaping ecologies and evolutionary change is still in its infancy. This book brings together a number of authors with the aim of helping to consolidate a better understanding of this interesting area of photobiology.

Spis treści

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.