Significance of Natural and Anthropogenic Changes in Ultraviolet Radiation to the Development of Anurans in Temperate South America

点击翻译按钮获取中文摘要

9631146 Fox Ultraviolet-B (UV-B) radiation is known to elicit strong selective pressures on life on earth. UV-B radiation has been increasing worldwide, and the Southern Hemisphere has experienced stronger increases in biologically active ultraviolet radiation than comparable latitudes in the Northern Hemisphere. The greater increase there is exemplified by the severe ozone hole that occurs over Antarctica each austral spring. The southern cone of South America provides a unique opportunity for studying the biological impacts of the austral spring ozone hole because it is the only land mass of significant size to reach the high latitudes of the Southern Hemisphere. Life there has been experiencing recent, severe, anthropogenically-elevated levels of UV-B radiation. The southernmost extent of any amphibian species in the world occurs in Patagonia, in the southern tip of South America. This is of particular significance in light of recent evidence of the lethal effects of ambient UV-B radiation on amphibians in North America, and the potential link of stratospheric ozone depletion to the proposed global decline in amphibian populations. UV-B field exposure experiments will be performed with eggs/larvae of South American anuran species (using a similar protocol to that of North American experiments) at high and low elevations in the mid to high latitudes of South America. Teratogenesis, growth inhibition, mortality, and DNA damage of larvae under different UV exposures will be quantified. This approach will allow us to accomplish the following objectives: (1) examine the ability of anuran species that lay their eggs in open water near the surface to mitigate the harmful effects of UV-B radiation across latitudinal and elevational gradients of UV-B radiation, and (2) determine if the large increase in biologically active UV-B radiation in the Southern Hemisphere is having a negative impact on early life stages in high latitude anuran species.