EGU22-3369
https://doi.org/10.5194/egusphere-egu22-3369
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Climate signals in stable carbon and hydrogen isotopes of lignin methoxy groups: assessing the potential for temperature reconstructions at different spatial and temporal scales

Anna Wieland1, Markus Greule1, Philipp Roemer2, Jan Esper2,3, and Frank Keppler1,4
Anna Wieland et al.
  • 1Institute of Earth Sciences, Ruprecht Karls University, Heidelberg, Germany (anna.wieland@geow.uni-heidelberg.de)
  • 2Department of Geography, Johannes Gutenberg University, Mainz, Germany
  • 3Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic
  • 4Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany

Stable hydrogen and carbon isotope ratios of wood lignin methoxy groups (δ13CLM and δ2HLM values) have been shown to be reliable proxies of past temperature variability. Recent studies revealed δ2HLM values even work in temperate environments where classical tree-ring width and maximum latewood density data are less skilful. In this presentation, we report 100 years of annually resolved δ13CLM values of four beech trees (Fagus sylvatica) from a temperate site near Hohenpeißenberg in southern Germany. The series are compared with regional to continental scale climate observations to assess their potential for paleoclimate reconstruction. The δ13CLM values were corrected for both the Suess effect to mitigate the effect of decreasing δ13C in atmospheric CO2 and the physiological tree response to increasing atmospheric CO2 concentrations using different factors for possible changes in discrimination. The calibration of δ13CLM chronologies against regional instrumental data reveals highest temperature sensitivity with mean summer, annual, and previous-year September to current-year August temperatures.

We additionally compared the new δ13CLM chronology with the previously produced δ2HLM series of the same trees to evaluate the additional gain of assessing past climate variability using a dual-isotope approach. The δ2HLM values predominantly reflect large-scale temperatures since highest correlations were found with western European temperatures. Weak and mainly non-significant correlations were found between precipitation and both isotopic chronologies (δ13CLM and δ2HLM values). Our findings described for the first time the great potential of using δ13CLM values from temperate, low elevation environments as a proxy for local temperatures, whereas the combination of both proxies supports the reconstruction of temperature variations at different spatial and temporal scales.

How to cite: Wieland, A., Greule, M., Roemer, P., Esper, J., and Keppler, F.: Climate signals in stable carbon and hydrogen isotopes of lignin methoxy groups: assessing the potential for temperature reconstructions at different spatial and temporal scales, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3369, https://doi.org/10.5194/egusphere-egu22-3369, 2022.

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