Collaborative Research: A millennial-scale chronicle of organism-environment interactions resulting in microevolutionary physiological and genomic shifts in Daphnia

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A central challenge facing contemporary biology is to understand how organisms adapt to changing environments. This research focuses on whether predictions of microevolutionary shifts in the physiology of animal populations can be based on ecosystem-level information. Answers to such questions should foster better forecasting models of global environmental change and inform effective management. Using a unique model organism, Daphnia, a small crustacean that lives in lakes and produces resting eggs that can lay dormant in sediments for centuries, the Principal Investigators (PIs) have been able to directly observe the evolutionary consequences of man-made change in a natural population. In this project, the PIs will elucidate the precise mechanisms that underlie observed evolutionary shifts coinciding with changes in key environmental parameters such as phosphorus (P) loading history (i.e., nutrient enrichment that affects water quality). Specifically, they will use cutting-edge paleolimnological tools to examine lake-bottom sediments to precisely reconstruct erstwhile environments reflective of pre- and post-European settlement, and use that information to test the performance of ancient and extant Daphnia genotypes to assess anthropogenic impacts. Furthermore, they will couple experimental evolution, and high throughput genomics methods to identify the genes that underlie such evolutionary shifts. The performance of these genes in predicting responses to nutrient enrichment (i.e., eutrophication) in a different lake will also be assessed. The PIs will continue to recruit students from underrepresented groups at various levels (high-school, undergraduate, and graduate). This project will train a postdoctoral fellow, three graduate research students, a museum intern, three undergraduate research assistants, and a high school intern. The genomic information generated from the proposed experiments will be made available to the scientific community via www.wFleabase.org as soon as possible, while the Daphnia clone bank generated during this project will be shared after the duration of the grant. Moreover, results from this study are relevant to issues of water quality and environmental change (particularly from paleolimnological assays), and the PIs will continue to share data with the Minnesota Department of Natural Resources for outreach to lake managers and the general public. In partnership with the Science Museum of Minnesota, the project will be part of the NSF-sponsored award-winning www.sciencebuzz.org online exhibits that blend up-to-the-minute science news (via RSS technology) with traditional museum interactive experiences, reaching potentially 500,000-800,000 individuals per year. The PIs will provide content on global environmental change, particularly related to lakes, and the ability of aquatic organisms to adapt to changing conditions. Finally, this work contributes to and benefits from federally-funded resources such as the Daphnia Genomics Consortium and the National Lacustrine Core Facility.