|
|||||
|
|
Palaeoenvironmental Reconstructions Based on Geochemical Parameters from Annually Laminated Sediments of Sacrower See (northeastern Germany) Since the 17th Century |
|
| Authors: | Britta Lüder Gerald Kirchner Andreas Lücke Bernd Zolitschka |
| Institution: | 1. GEOPOLAR, Institute of Geography, University of Bremen, Celsiusstra?e FVG-M, D-28359, Bremen, Germany 2. Department of Physics, University of Bremen, D-28359, Bremen, Germany 3. Bundesamt für Strahlenschutz, D-38226, Salzgitter, Germany 4. Institute of Chemistry and Dynamics of the Geosphere, Research Centre Jülich, D-52425, Jülich, Germany |
| Abstract: | The history of hardwater lake Sacrower See (Brandenburg, northeastern Germany) was reconstructed back to the 17th century based on a multi-proxy study of five short sediment cores dated by varve chronology, 210Pb and 137Cs isotopes. We were able to distinguish three main phases: The lake was mesotrophic prior to the 1830s with an oxic hypolimnion. From the early 19th century on, δ13C of organic matter indicates that primary productivity starts to increase slowly. Between the 1830s and 1872, the lake went through a transition towards eutrophy. Low calcite contents in the homogeneous sediment are caused by dissolution connected to increasing primary productivity and growing importance of decomposition processes. After 1873, and accelerated since 1963, Sacrower See is characterised by growing nutrient input, and thus further increasing primary productivity. The lake is eutrophic, and decomposition of organic matter causes high oxygen consumption in the hypolimnion, which becomes regularly anoxic during thermal summer stratification. Biogenic varves are preserved in the sediment, characterised by layers of autochthonous, biochemically precipitated calcite crystals. In this study, we were able to demonstrate that Sacrower See is an example of exceptional slow increase of anthropogenically enhanced nutrient input, and of the imprint which these processes have on sediments of a hardwater lake. |
| Keywords: | Biogenic varves δ 13C of organic matter Calcite Eutrophication Human impact Lake sediments |
| 本文献已被 SpringerLink 等数据库收录！ | |