Lead and Lags of Lake System Responses to Late Allerød and Early Younger Dryas Climatic Fluctuation – an Example from Varved Lake Sediments from Northern Poland (Central Europe)

Monday, 15 December 2014: 4:30 PM
Michal M. Slowinski1,2, Izabela Zawiska3, Florian Ott1, Agnieszka M. Noryśkiewicz4, Birgit Plessen1, Karina Apolinarska5, Monika Lutyńska6, Danuta J. Michczynska7, Sabine Wulf1, Piotr Skubała8, Mirosław Błaszkiewicz2 and Achim Brauer1, (1)Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Section 5.2: Climate Dynamics and Landscape Evolution, Potsdam, Germany, (2)Institute of Geography and Spatial Organization, Polish Academy of Sciences,, Department of Environmental Resources and Geohazards, Torun, Poland, (3)Institute of Geography and Spatial Organization, Polish Academy of Sciences, Department of Geoecology and Climatology, Warsaw, Poland, (4)Nicholas Copernicus University, Institute of Archaeology, Torun, Poland, (5)Adam Mickiewicz University, Institute of Geology, Poznań, Poland, (6)Adam Mickiewicz University, Department of Geology and Quaternary Paleogeography, Poznań, Poland, (7)CSE Silesian University of Technology, Department of Radioisotopes Institute of Physics, Gliwice, Poland, (8)University of Silesia, Department of Ecology, Katowice, Poland
The transition from the warmer Allerød to the cooler Younger Dryas period is well understood to represent sudden and extreme climate changes during the end of the last glaciation. Thus, lake sediment studies within paleoclimatic and paleoecological research on this transition are ideal to enhance the knowledge about “lead and lags” of lake system responses to abrupt climate changes through applying multi-proxy sediment analyses.

In this study, we present the results of high-resolution studies on varved late glacial sediments from the Trzechowskie paleolake, located in the northern Poland (center Europe).

High-resolution bio-proxies (pollen, macrofossils, Cladocera and diatoms), geochemical analyses (µ-XRF data, TOC, C/N ratios, δ18Ocarb and δ13Corg stable isotopes) and a robust chronology based on varve counting, AMS 14C dating and tephrochronology were used to reconstruct the lake system responses to rapid climatic and environmental changes of Trzechowskie paleolake during the late Allerød - Younger Dryas transition. Paleoecological and geochemical analyses, which were carried out in a 4 to 16 years temporal sample resolution, allowed to defining short-termed shifts of the ecosystem that were triggered by abrupt climate changes.

The rapid and pronounced cooling at the beginning of the Younger Dryas had a major impact on the lake and its catchment as clearly reflected by not synchronous changes of both, biotic and geochemical proxies. The results of high-resolution analysis indicate (a) an increased precipitation during the Allerød-YD transition, which is responsible for an increase of soil erosion in the catchment during this period, (b) a delayed response of the vegetation compared to the lake depositional system at the YD onset of 20 years, and (c) a non-synchronicity of vegetation responses between Western (Lake Meerfelder Maar) and Eastern European sites (Trzechowskie palaeolake) at the YD onset.

This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association. The research was supported by the National Science Centre Poland (grants No. NN 306085037 and NCN 2011/01/B/ST10/07367).