We apply (isotope-) geochemical and lipid biomarker analyses to lacustrine sediment records in various Swiss lakes with the goal to reconstruct past changes in climatic conditions (e.g., paleo-thermometry using GDGTs), primary productivity (e.g., the δ13C of authigenic CaCO3 and organic matter), nutrient loading and utilization (δ15Norg) and redox conditions (e.g., trace metal concentrations and biomarker/fossil DNA that indicate the existence of anaerobic microorganisms). We are particularly interested in the more recent history of (de-) eutrophication of Swiss lakes and the associated geochemical signatures within the sediments. In this context, long-term hydro- and biogeochemical data sets from ongoing monitoring programs led by our collaborators (eg. SUPSI and the Canton of Ticino) are extremely valuable for the calibration of the paleo-limnological proxies and for testing their sensitivity towards environmental change. In collaboration with the ETH Zurich and the University of Berne, we also study longer-term climate variability and perturbations of lacustrine biogeochemical cycles over the Holocene period (e.g., in Lake Cadagno, Soppensee).