Collaborative Research: Organism-environment interactions - impact of cultural eutrophication on Daphnia tracked by genomics, physiology and resurrection ecology

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Given the important role that organisms (including man) play in ecosystem processes, it is surprising that little work has examined how man-made environmental changes affect the way organisms evolve and adapt. In a planned 36-month project, the PIs will use an integrated approach involving genetic/genomic, physiological, and 'resurrection ecology' methods to examine how cultural eutrophication (i.e., enrichment of freshwater systems with nutrients such as phosphorus) influences evolutionary changes in organisms. The waterflea, Daphnia pulex, which plays a major role in freshwater food webs (i.e. it eats algae/bacteria and in turn is fed upon by fish), will serve as the model organism. Daphnia are ideal for such studies because they produce resting eggs that can lay dormant in lake sediments for long periods of time. Decades-old eggs can be induced to hatch (i.e. 'resurrection ecology') and viable DNA can be extracted from eggs that are centuries old. Moreover, the D. pulex genome has been sequenced and genetic/genomic methods (i.e. gene expression) are in place to study how changes in eutrophication (phosphorus-level) patterns over the past century have influenced how an organism like a daphniid can respond to ecosystem/environmental change. The PIs expect to find distinct changes in the genetic structure and physiological mechanisms of different populations 'resurrected' from different sediment (time) layers in the resting egg bank from lakes that differ in eutrophication history. Results from this cross-disciplinary study will provide an excellent example of how man-made environmental changes (via eutrophication) influence natural (freshwater) ecosystems. Academic (i.e. university) researchers, applied researchers (e.g., lake managers), and members of the general public (i.e. recreational users) should be keenly interested in the results from this project. Educational training opportunities will include Native American high school interns as research assistants. Results will be published in peer-reviewed journals, while presentations to both scholarly and general-public audiences are planned.