DISSERTATION RESEARCH: Adaptation to variable ultraviolet radiation threats in alpine Daphnia populations.

生物体是如何通过自然选择进化来忍受环境中的压力的？在这个项目中，研究人员试图了解淡水动物是如何进化到能够忍受高山生态系统中清澈池塘中有害的紫外线辐射的。研究人员集中研究了华盛顿州奥林匹克国家公园高山池塘中广泛存在的浮游动物水蚤，这些池塘从透明度到紫外线辐射的范围都有。研究人员从三个方面着手：1)了解不同种群对紫外线辐射的耐受性是如何变化的；2)了解对紫外线辐射的耐受性是否是一种诱导性状；3)利用遗传和分析方法阐明自然选择在水蚤种群适应环境中紫外线辐射威胁过程中所起的作用。据了解，全球气候变化对水下紫外线辐射的间接影响比臭氧空洞的影响更强。这个项目将扩大我们对浮游动物种群是如何进化到在高紫外线辐射下持续存在的理解。这将作为一个预测模型，说明其他种群在面对气候变化和管理战略时是否能够坚持下去。因此，这个项目的智力贡献是双重的，特别是告诉我们对高山栖息地浮游动物对环境压力的反应的理解和预测，更广泛地阐明了在全球气候变化时代，种群如何适应可变环境压力的进化过程。

How do organisms evolve via natural selection to tolerate stresses in their environments? In this project the investigators seek to understand how freshwater animals have evolved to tolerate harmful ultraviolet radiation in the clear-water ponds of an alpine ecosystem. The investigators focus on the widespread zooplankton Daphnia pulex in alpine ponds that span a range of transparencies to ultraviolet radiation in Olympic National Park, WA. The investigators pursue three lines of inquiry: 1) to understand how tolerance of ultraviolet radiation varies among populations, 2) to understand whether the tolerance of ultraviolet radiation is an inducible trait, and 3) to use genetic and analytical methods to elucidate the role of evolution by natural selection in adapting populations of Daphnia to the ultraviolet radiation threats in their environment.The indirect effects of global climate change on underwater ultraviolet radiation regimes are understood to be stronger than the effect of the ozone hole. This project will expand our understanding of how a zooplankton population has evolved to persist in the presence of high ultraviolet radiation exposure. This will serve as a predictive model for how other populations may or may not be able to persist in the face of climatic changes and management strategies. The intellectual contributions of this project are therefore twofold, specifically informing our understanding and predictions of zooplankton responses to environmental stress in alpine habitats, and more broadly illuminating the evolutionary process of how populations adapt to variable environmental pressures in an era of global climate change.