Landscape disturbance and climate change affect lakes in proportion to their contact with ground water, sometimes resulting in different responses in neighboring lakes. This project develops methods for reconstructing past water chemistry and food webs of lakes. The biological and chemical deposits in surface sediment samples will be compared with the water in 62 modern lakes. The resulting relationships will be tested by comparing sediment cores with 24 years of observations from the North Temperate Lakes Long Term Ecological Research (NTL-LTER) site. The methods will then be used to reconstruct 150 years of history for several lakes, adding perspective to the long-term observations of the NTL-LTER and testing the prediction that lakes high in the local landscape had more severe and longer-lasting effects of 19th century logging than low lakes that are more influenced by groundwater. This research will also help to understand the response of lakes to severe droughts that last decades to centuries by identifying periods of low lake levels during the last 10,000 years. Understanding the variability of the responses of lakes to climate change and disturbance is essential to predicting the responses of particular lakes to future changes in land use and climate. This project will bring together expertise from several strong programs at the University of Wisconsin (the Center for Limnology, Botany, the Center for Climatic Research, NTL-LTER, and UW-LaCrosse), with the Limnological Research Center and LacCORE National Lacustrine Core Repository at the University of Minnesota and the United States Geologic Survey Water, Energy, and Biogeochemical Budgets (WEBB) project. Cores collected in this project will be archived at LacCORE and made available to future researchers, forging important new links between the LTER network, the paleoecology and paleoclimate communities, and groundwater scientists at the USGS. Two graduate students and at least 10 undergraduates will participate, and the project will contribute to the Limnology Explorers program, an interdisciplinary educational experience for middle school students coordinated by the NTL-LTER and the UW Center for Biology Education as part of the SchoolYard LTER initiative.
