Ecosystems, Evolution, and Ultraviolet Radiation

This book discusses UV radiation, its effects on ecosystems and the li kely evolutionary consequences of changed UV radiation environments, p ast, present and future. The first two chapters examine the history of the UV radiation climate of earth and the factors that determine orga nismal and ecosystem exposure. Their purpose is to give the reader a p hysical perspective on UV radiation and an understanding of the consta ntly 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-sca le changes (such as alterations in the column abundance of UV-B protec ting ozone). UV radiation regimes also vary over temporal scales. Thes e alterations occur on time scales of seconds (the movement of clouds and plant canopies) to literally billions of years (gross long-term ch anges in the composition of the Earth's atmosphere).