Grant: Discovery Grants Program - Individual

My research explores how environmental changes shape ecosystems over centuries and millennia. These questions require a long-term perspective to place recent changes in the context of long-term variability. This long-term outlook is lacking from most environmental studies, which are limited by short time scales that do not permit estimations of natural variability. My focus extends the horizon of environmental research by harnessing the power of lake sediment cores as archives of long-term environmental change. Here I propose to continue to advance this field by developing innovative approaches to reconstruct environmental change in lake sediments. Specifically, I will 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 from lake sediment core records. Recent analytical advances in my laboratory have made significant progress in developing targeted methods to track climatic anomalies. One such tool is temperature-sensitive lipid markers present in microbial membranes, which allow us to track past changes in climate. I have recently augmented our capabilities by developing "non-targeted biomarker discovery" to identify new persistent organic markers in sediments from different ecozones, such as Boreal and Tundra lakes. These biomarkers are shedding new light on how Canada's ecosystems have changed in recent millennia. In the coming 5 years, I propose to apply my novel approaches to track population dynamics in seabirds and Arctic human inhabitants, which I will then apply to sediment cores from lakes using advanced radiometric dating methods. This analysis will allow my team to better characterize the variability of these populations. The seabirds I have chosen for this work form very large colonies and show high site fidelity, making them ideally suited for studies of sedimentary deposits to track population abundance. The Thule settled in specific locations with well characterized archeological information, but I will use lake sediment cores to unlock more refined details about their occupation, including details of flora and fauna using sediment DNA. Recently, my lab has established the use of fecal sterols and stanols as a tool to reconstruct inputs to lake sediments originating from seabirds and human settlements, raising the potential for sterol fingerprinting sources of these populations to lakes. Using a multi-proxy approach that includes analysis of stable isotopes, biogenic elements, and more specific biomarkers, I propose to collect and analyze sediment cores adjacent to major seabird colonies and human settlements. This analysis will allow us to track the arrival and long-term stability of populations and to use this information to address key issues linked to conservation biology, ecosystem dynamics, and natural versus anthropogenic drivers of ecosystem change.