Developing new approaches to track environmental change using lake sediment archives.

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My research and HQP training aims to answer questions requiring a long-term perspective on the effects of anthropogenic disturbances and environmental perturbations on ecosystems. This long-term perspective is needed because most environmental studies are limited by short time scales that do not permit sufficient estimations of natural variability. I focus much of my research and HQP training on lake sediment cores as archives for reconstructing long term environmental change. Here I propose to continue to advance this field by developing new approaches for reconstructing environmental change in lake sediments. Specifically, I propose to develop and apply new tools to demonstrate how aquatic environments have been altered by warming northern climates and migratory animals, and examine how these processes may be reconstructed throughout the Holocene in lake sediment cores.*******Recent analytical advances in my laboratory have developed targeted analytical methods for analyzing source-specific markers to study changes in allochthonous matter to lakes to show, for example, that lake expansion in the Mackenzie Bison Sanctuary is unprecedented in recent centuries. I have recently augmented this work by developing “non-targeted biomarker discovery” to identify new persistent organic markers in sediments from different ecozones (such as Boreal and Tundra lakes) in an effort to show how Canada's ecosystems have changed in recent centuries and millennia. This new approach provides unique HQP training opportunities in molecular marker discovery that is traditionally used in other disciplines, and uniquely applying them to sediment studies. Specifically, I propose to identify and apply the next generation of sediment markers to determine, for example, how tree line has shifted in previous centuries in response to changing climate in radiometrically dated lake sediment cores.*******Another methodology I propose to examine is to develop markers preserved in lake sediment cores to reconstruct inputs from migratory animals and early human settlements to study the natural variability of these populations. Recently, my lab has advanced the use of fecal sterols and stanols to reconstruct nutrients to lake sediments from seabirds, raising the potential for sterol fingerprinting sources of fecal inputs to lakes. Using a multi-proxy approach, I propose to collect sediment cores adjacent to seabird colonies and human settlements in an effort to determine the arrival and long-term stability of populations by tracking source-specific markers to lake sediment cores, and to use this information to address key issues linked to conservation biology, ecosystem dynamics, and natural versus anthropogenic drivers of ecosystem change.******