Seasonal variability of Holocene climate: a palaeolimnological study on varved sediments in Lake Jues (Harz Mountains, Germany)
| Autor: | Dieter Meischner, Janina Baier, Ricarda Voigt, Eberhard Grüger |
|---|---|
| Přispěvatelé: | 5.2 Climate Dynamics and Landscape Evolution, 5.0 Earth Surface Processes, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum |
| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
0106 biological sciences
010506 paleontology Palaeolimnology Holocene climate Diatoms Green algae Pollen Karst Climate change 550 - Earth sciences Aquatic Science 01 natural sciences law.invention law Albrecht-von-Haller-Institut für Pflanzenwissenschaften / Abteilung für Palynologie und Klimadynamik medicine Radiocarbon dating Sedimentology Holocene 0105 earth and related environmental sciences Earth-Surface Processes Varve 010604 marine biology & hydrobiology 15. Life on land Seasonality medicine.disease Preboreal Oceanography Boreal 13. Climate action Geology |
| Zdroj: | Journal of Paleolimnology |
| Popis: | Studies combining sedimentological and biological evidence to reconstruct Holocene climate beyond the major changes, and especially seasonality, are rare in Europe, and are nearly completely absent in Germany. The present study tries to reconstruct changes of seasonality from evidence of annual algal successions within the framework of well-established pollen zonation and 14C-AMS dates from terrestrial plants. Laminated Holocene sediments in Lake Jues (10°20.7? E, 51°39.3? N, 241 m a.s.l.), located at the SW margin of the Harz Mountains, central Germany, were studied for sediment characteristics, pollen, diatoms and coccal green algae. An age model is based on 21 calibrated AMS radiocarbon dates from terrestrial plants. The sedimentary record covers the entire Holocene period. Trophic status and circulation/stagnation patterns of the lake were inferred from algal assemblages, the subannual structure of varves and the physico-chemical properties of the sediment. During the Holocene, mixing conditions alternated between di-, oligo- and meromictic depending on length and variability of spring and fall periods, and the stability of winter and summer weather. The trophic state was controlled by nutrient input, circulation patterns and the temperature-dependent rates of organic production and mineralization. Climate shifts, mainly in phase with those recorded from other European regions, are inferred from changing limnological conditions and terrestrial vegetation. Significant changes occurred at 11,600 cal. yr. BP (Preboreal warming), between 10,600 and 10,100 cal. yr. BP (Boreal cooling), and between 8,400 and 4,550 cal. yr. BP (warm and dry interval of the Atlantic). Since 4,550 cal. yr. BP the climate became gradually cooler, wetter and more oceanic. This trend was interrupted by warmer and dryer phases between 3,440 and 2,850 cal. yr. BP and, likely, between 2,500 and 2,250 cal. yr. BP. peerReviewed |
| Databáze: | OpenAIRE |
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