Seasonality of the altitude effect on leaf wax n-alkane distributions, hydrogen and carbon isotopes along an arid transect in the Qinling Mountains.

Jinzhao Liu

The Science of the total environment 2021 Jul 15

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Reconstructing paleoelevation allows the temporal evolution of biogeochemical processes and hydroclimate regimes to be understood and quantified. A dual-isotope biomarker of clumped hydrogen and carbon isotopes of leaf wax n-alkanes was recently proposed in humid tropical forests, and it was proven to be superior to a single-isotope proxy that was previously reported. However, it remains unknown whether the dual-isotope biomarker is suitable in arid conditions. The present study investigated leaf wax n-alkane distribution, hydrogen (δ2Hwax) and carbon (δ13Cwax) isotopes in terrestrial plants along an arid mountainous transect. We found that the effects of seasonality on n-alkane distribution, δ2Hwax and δ13Cwax were minimal for all species (p > 0.05), and that species-specific δ2Hwax values remained almost unchanged for most species, in contrast to δ13Cwax values. Significant correlations between altitude and δ2Hwax values (R2 = 0.54, 0.58, and 0.75 for spring, summer, and autumn, respectively), instead of δ13Cwax values (R2 = 0.08, 0.43, and 0.12 with p = 0.24, 0.01, and 0.19 for spring, summer, and autumn, respectively), were observed, suggesting that δ2Hwax values, but not δ13Cwax values, can be reliably used as a proxy for reconstructing paleoelevation in arid conditions. Therefore, it will be necessary to identify other proxies to supplement δ2Hwax values under a dual-isotope approach in future research. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Jinzhao Liu. Seasonality of the altitude effect on leaf wax n-alkane distributions, hydrogen and carbon isotopes along an arid transect in the Qinling Mountains. The Science of the total environment. 2021 Jul 15;778:146272