EGU22-7518, updated on 28 Mar 2022
https://doi.org/10.5194/egusphere-egu22-7518
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impacts of post-photosynthetic fractionation on the carbon isotopic composition of leaf wax n-alkanes under elevated CO2

Bridget Warren, James Bendle, Kweku Afrifa Yamoah, and Yvette Eley
Bridget Warren et al.
  • School of Geography, Earth and Environmental Science, University of Birmingham, Birmingham, UK

The carbon isotopic composition of plant wax n-alkanes (δ13Cn-alkane) is a well-established proxy for bulk plant δ13C, which itself reflects plant community composition and palaeohydrology in the geologic record. Although the biosynthetic processes which form n-alkanes cause a depletion in 13C relative to bulk plant tissue, it is generally presumed that this depletion is constant. In particular, on geologic timescales bulk plant δ13C is invariant to changes in atmospheric CO2, and it is therefore assumed that δ13Cn-alkane follows the same pattern. However, this assumption has not been tested, and it is possible that the biosynthetic fractionation during the formation of n-alkanes and other lipid biomarkers is affected by atmospheric CO2 concentration independently of trends in bulk plant tissue. Here, I use the Birmingham Institute of Forest Research (BIFoR)’s Free Air Carbon Enrichment experiment (FACE) to investigate the impact of elevated CO2 on both bulk and n-alkane δ13C in order to identify any such influence of elevated CO2 on n-alkane isotopic composition. If any such effects are detected, CO2 levels should be accounted for in interpretations of deep-time δ13Cn-alkane records.

How to cite: Warren, B., Bendle, J., Yamoah, K. A., and Eley, Y.: Impacts of post-photosynthetic fractionation on the carbon isotopic composition of leaf wax n-alkanes under elevated CO2, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7518, https://doi.org/10.5194/egusphere-egu22-7518, 2022.

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