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

众所周知，紫外线b （UV-B）辐射会对地球上的生命产生强烈的选择性压力。在世界范围内，UV-B辐射一直在增加，南半球生物活性紫外线辐射的增加比北半球可比纬度地区更强烈。每年南方春季在南极洲上空出现的严重臭氧空洞就是更大的增长的例证。南美洲的南锥体为研究南半球春季臭氧空洞的生物影响提供了一个独特的机会，因为它是唯一一个到达南半球高纬度地区的显著面积的陆地。最近，那里的生命经历了严重的、人为的UV-B辐射水平升高。世界上任何两栖动物物种的最南端出现在南美洲南端的巴塔哥尼亚。鉴于最近有证据表明环境紫外线- b辐射对北美两栖动物的致命影响，以及平流层臭氧消耗与拟议的全球两栖动物种群减少的潜在联系，这一点尤其重要。将在南美洲中高纬度地区的高海拔和低海拔地区对南美洲无尾猿的卵/幼虫进行UV-B野外暴露试验（使用与北美试验类似的方案）。对不同紫外线照射下的幼体致畸、生长抑制、死亡率和DNA损伤进行定量分析。这种方法将使我们能够实现以下目标：(1)检查在靠近地表的开放水域产卵的无尾猿物种减轻UV-B辐射在纬度和海拔梯度上的有害影响的能力，以及(2)确定南半球生物活性UV-B辐射的大量增加是否对高纬度无尾猿物种的早期生命阶段产生负面影响。

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.