Climate signal transfer to varved sediments in Lake Tiefer See near Klocksin - Monitoring, Transfer functions, quantitative Reconstructions

• Antragsteller: Professor Dr. Achim Brauer; Professor Dr. Reinhard Lampe
• Fachliche Zuordnung: Paläontologie
• Förderung: Förderung von 2013 bis 2018
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 235091068

The seasonal lamination of sediment deposition makes Lake Tiefer See near Klocksin (NE Germany) an excellent natural laboratory to study the direct link from meteorological (input signal) to sediment variables (output) with the objective to develop new proxies and response functions. The inverse transfer functions will complete the link between past and modern time scales and provide an important completion for the quantitative reconstructions in ICLEA . The proposed study benefits from TERENO -monitoring facilities coupled with technical and research support provided by the GFZ Potsdam. The project cooperation with the University Greifswald complements the ICLEA initiative providing competence in regional studies and scientific methods.The proposed monitoring is set up to analyze the transfer of input signals (meteorology) via lake responses (limnophysics, chemistry, biota) to the seasonal sediment layers: diatom blooms and carbonate precipitation (studied in the pelagial) and detritus input (studied in pelagial and littoral ). We will focus on hypotheses concerning the dynamics of temperature and wind: 1) wind-induced littoral resuspension entrained into temperature-induced lake circulation increases detritus deposition, 2) wind-induced intermittent disturbance in the epilimnion recycles nutrients, which fuel diatom blooms and carbonate precipitation, and 3) water temperature at the time of major carbonate precipitation is archived in its oxygen isotope signature. Sediment response variables are the thickness and element composition of the seasonal layers, the stable isotope signature of carbonate precipitates, and the assemblage and carbon isotope signature of diatom-organic matter.Significant input-output relations extracted from the monitoring dataset will be calibrated with long meteorological series. The transfer-function based quantitative reconstructions from the seasonally laminated sediment will greatly add to our knowledge about the postglacial climatic and environmental development in NE Germany.Insight into lake-level dynamics will be added from lake-basin mapping in support of core transects, which are set up to track the water depth at which deposition exceeds abrasion and the depth limit of varved sedimentation. Related with soil sampling, monitoring of dust deposition, resuspension and redeposition along the main wind direction (WSW), we attempt to reconstruct the patterns of deposition and provenance of detritus. A validate time chart of human activities will help to differentiate these anthropogenic effects from climatic influence.The link of the proposed project with results of an associate ICLEA monitoring and varved-sediment study in continental NE Poland offers a wider perspective pertaining to the influence and, in reverse, reconstruction of large-scale climate patterns as the North Atlantic Oscillation.

• DFG-Verfahren: Sachbeihilfen