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.
