TY  - JOUR
A1  - Obreht, Igor
A1  - Wörmer, Lars
A1  - Brauer, Achim
A1  - Wendt, Jenny
A1  - Alfken, Susanne
A1  - De Vleeschouwer, David
A1  - Elvert, Marcus
A1  - Hinrichs, Kai-Uwe
T1  - An annually resolved record of Western European vegetation response to Younger Dryas cooling
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - The regional patterns and timing of the Younger Dryas cooling in the North Atlantic realm were complex and are mechanistically incompletely understood. To enhance understanding of regional climate patterns, we present molecular biomarker records at subannual to annual resolution by mass spectrometry imaging (MSI) of sediments from the Lake Meerfelder Maar covering the Allerod-Younger Dryas transition. These analyses are supported by conventional extraction-based molecular-isotopic analyses, which both validate the imaging results and constrain the sources of the target compounds. The targeted fatty acid biomarkers serve as a gauge of the response of the local aquatic and terrestrial ecosystem to climate change. Based on the comparison of our data with existing data from Meerfelder Maar, we analyse the short-term environmental evolution in Western Europe during the studied time interval and confirm the previously reported delayed hydrological response to Greenland cooling. However, despite a detected delay of Western European environmental change of similar to 135 years, our biomarker data show statistically significant correlation with deuterium excess in Greenland ice core at - annual resolution during this time-transgressive cooling. This suggests a coherent atmospheric forcing across the North Atlantic realm during this transition. We propose that Western European cooling was postponed due to major reorganization of the westerlies that were intermittently forcing warmer and wetter air masses from lower latitudes to Western Europe and thus resulted in delayed cooling relative to Greenland.
KW  - lateglacial
KW  - paleoclimatology
KW  - Western Europe
KW  - Meerfelder Maar
KW  - high-resolution biomarkers
KW  - fatty acids
KW  - FT-ICR-MS
KW  - mass spectrometry
KW  - imaging
Y1  - 2020
U6  - https://doi.org/10.1016/j.quascirev.2020.106198
SN  - 0277-3791
VL  - 231
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Rach, Oliver
A1  - Engels, S.
A1  - Kahmen, A.
A1  - Brauer, Achim
A1  - Martin-Puertas, C.
A1  - van Geel, B.
A1  - Sachse, Dirk
T1  - Hydrological and ecological changes in western Europe between 3200 and 2000 years BP derived from lipid biomarker delta D values in lake Meerfelder Maar sediments
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - One of the most significant Late Holocene climate shifts occurred around 2800 years ago, when cooler and wetter climate conditions established in western Europe. This shift coincided with an abrupt change in regional atmospheric circulation between 2760 and 2560 cal years BP, which has been linked to a grand solar minimum with the same duration (the Homeric Minimum). We investigated the temporal sequence of hydroclimatic and vegetation changes across this interval of climatic change (Homeric climate oscillation) by using lipid biomarker stable hydrogen isotope ratios (ED values) and pollen assemblages from the annually-laminated sediment record from lake Meerfelder Maar (Germany). Over the investigated interval (3200-2000 varve years BP), terrestrial lipid biomarker ED showed a gradual trend to more negative values, consistent with the western Europe long-term climate trend of the Late Holocene. At ca. 2640 varve years BP we identified a strong increase in aquatic plants and algal remains, indicating a rapid change in the aquatic ecosystem superimposed on this long-term trend. Interestingly, this aquatic ecosystem change was accompanied by large changes in ED values of aquatic lipid biomarkers, such as nC(21) and nC(23) (by between 22 and 30%(0)). As these variations cannot solely be explained by hydroclimate changes, we suggest that these changes in the Wag value were influenced by changes in n-alkane source organisms. Our results illustrate that if ubiquitous aquatic lipid biomarkers are derived from a limited pool of organisms, changes in lake ecology can be a driving factor for variations on sedimentary lipid MN values, which then could be easily misinterpreted in terms of hydro climatic changes. (C) 2017 Elsevier Ltd. All rights reserved.
KW  - Holocene
KW  - Climate dynamics
KW  - Paleoclimatology
KW  - Western Europe
KW  - Continental biomarkers
KW  - Organic geochemistry
KW  - Stable isotopes
KW  - Vegetation dynamics
Y1  - 2017
U6  - https://doi.org/10.1016/j.quascirev.2017.07.019
SN  - 0277-3791
VL  - 172
SP  - 44
EP  - 54
PB  - Elsevier
CY  - Oxford
ER  -