104B Base Grants – Using Sedimentary Lipid Biomarkers

Ecosystem disturbances in the Laurentian Great Lakes threaten the aquatic food web and water quality. Freshwater aquatic communities of Lake Michigan are faced with a wide array of environmental stressors that are likely in increase in the coming century, including invasive species, nutrient loading, and climate change. The numbers of species, community structure, and range of organisms will be altered as water quality, temperature, clarity, seasonal and annual water availability, and nutrient loading all differ from present conditions. However, significant uncertainty remains in how aquatic communities are impacted by disturbance over longer periods of time and how recovery of these communities progresses. Historical trends reconstructed from sediments can inform our management strategies as we learn of aquatic ecosystem response to disturbance and shifting community dynamics associated with recovery. Sediment reconstructions are necessary to examine processes operating over longer periods of time than can be observed, and can help constrain ecosystem behavior with overlapping disturbances. Here we propose to use organic biomarkers preserved in the sediments of Lake Michigan to reconstruct aquatic communities, water temperature, and hydroclimate.