Corrigendum: Leaf Waxes and Hemicelluloses in Topsoils Reflect the δ2H and δ18O Isotopic Composition of Precipitation in Mongolia

Institute of Geography, Friedrich Schiller University Jena, Jena, Germany, Heisenberg Chair of Physical Geography with Focus on Paleoenvironmental Research, Institute of Geography, Technical University of Dresden, Dresden, Germany, Institute of Agronomy and Nutritional Sciences, Soil Biogeochemistry, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany, Institute of Plant and Agricultural Sciences, Mongolian University of Life Sciences, Ulaanbaatar, Mongolia, Institute of General and Experimental Biology, Russian Academy of Science (RAS), Ulan-Ude, Russia, Institute of Soil Science and Soil Geography, University of Bayreuth, Bayreuth, Germany

In the original article, the presented δ 18 O ara values were accidentally not corrected for the oxygen introduced during hydrolysis. The necessary correction results in slightly more positive δ 18 O ara values.
The authors apologize for this mistake, and state that this does not change the scientific conclusions of the article in any way, particularly the fact that the calculated apparent fractionation (Ɛ 18O ara/p ) is constant along the Mongolian transect. However, as the apparent fractionation is 44 ± 2‰ (not 41 ± 2‰) and this would affect future data compilations and comparisons, we have corrected all δ 18 O ara and Ɛ 18O ara/p values in the text, the figures, and the supplementary material. We delete our hypothesis stated in the Supplementary Material that a decreasing partial CO 2 pressure might cause enhanced 18 O ara enrichment, because the correlation between Ɛ 18O ara/p and altitude is not significant anymore (R 2 0.09, p 0.14). All changes are highlighted in bold.
A correction has been made to the Abstract. The corrected version is as follows: "The apparent fractionation Ɛ app , i.e., the isotopic difference between precipitation and the investigated compounds, shows no strong correlation with climate along the transect (Ɛ 2H n-C29/p −129 ± 14‰, Ɛ 2H n-C31/p −146 ± 14‰, and Ɛ 18O ara/p +44 ± 2‰). Our results suggest that δ 2 H n-alkane and δ 18 O ara in topsoils from Mongolia reflect the isotopic composition of precipitation and are not strongly modulated by climate. Correlation with the isotopic composition of precipitation has root-mean-square errors of 13.4‰ for δ 2 H n-C29 , 12.6 for δ 2 H n-C31 , and 2.2‰ for δ 18 O ara , so our findings corroborate the great potential of compound-specific δ 2 H n-alkane and δ 18 O ara analyzes for paleohydrological research in Mongolia". A correction has been made to the Results. The corrected version is as follows: "The δ 18 O ara values range from +31‰ to +41‰ with an average of +35 ± 3‰ ( Figure 2B). All compounds show the same trend as the isotopic composition of precipitation ( Figures 2E,F), and are significantly more positive in the arid part of the transect (ID: 34-42) compared to the rest (δ 2 H n-C29 : p 0.017, δ 2 H n-C31 : p 7.08e −4 , δ 18 O ara : p 2.95e −5 ). FIGURE 2 | δ 2 H and δ 18 O signatures of leaf wax-derived n-alkanes and the hemicellulose sugar arabinose as well as their apparent isotope fractionation (Ɛ app ), compared to environmental and climatic parameters along the transect (A) Compound-specific δ 2 H of the leaf wax-derived n-alkane n-C 29 (black) and n-C 31 (green) (this study) (B) compound-specific δ 18 O ara (this study) (C) Ɛ 2H n-C29/p (black) and Ɛ 2H n-C31/p (green) (this study) (D) Ɛ 18O ara/p (this study) (E, F) OIPC isotopic composition of precipitation (black line) and amount-weighted isotopic signature of precipitation (blue line): δ 2 H p (E), and δ 18 O p (F), respectively (Bowen et al., 2005;Bowen,  Ɛ 18O ara/p ranges from +39‰ to +48‰ with an average of +44 ± 2‰ ( Figure 2D). Ɛ app is not statistically different in the arid part of the transect (Ɛ 2H n-C29/p : p 0.791, Ɛ 2H n-C31/p : p 0.554, Ɛ 18O ara/p : p 0.824)".
A correction has been made to Discussion, δ 2 H n-alkane and δ 18 O ara Against the Isotopic Composition of Precipitation. The corrected version is as follows: "The δ 2 H n-alkane and δ 18 O ara values correlate significantly with the δ 2 H p-WM and δ 18 O p-WM values (Figure 3, R 2 0.30, p 3.22e −4 for δ 2 H n-C29 ; 0.11 and 0.03 for δ 2 H n-C31 ; and 0.36 and 1.60e −3 for δ 18 O ara ).
The RMSE is 13.4‰ for δ 2 H n-C29 , 12.6‰ for δ 2 H n-C31 and 2.2‰ for δ 18 O ara (Figure 3) and thus indicates that the biomarkers accurately record the isotopic composition of precipitation along our transect".
A correction has been made to Discussion, Comparison With Other Studies. The corrected version is as follows: "The Ɛ 18O ara/p values for Mongolia (44 ± 2‰) are similar to values reported by Strobel et al. (2020) for relatively arid regions in South Africa. There, the more humid regions have a significantly lower Ɛ 18O ara/p (∼37‰), quite similar to the C 3 grass sites in Europe (Hepp et al., 2020). The deciduous tree sites in Europe, however, are again characterized by more enriched δ 18 O sugar values (Ɛ 18O sugar/p ∼43‰). All this indicates that δ 18 O is more sensitive to evapotranspirative enrichment than δ 2 H, so that climate can more strongly modulate δ 18 O sugar , and again that grasses show the signal dampening much more pronounced than dicotyledons". A correction has been made to the Conclusion. The corrected version is as follows: • "Leaf wax-derived n-alkanes and the hemicellulose-derived sugar arabinose are significantly more enriched in 2 H and 18 O in the more arid southern and eastern parts of the transect. This reflects the changes in the isotopic composition of precipitation along the transect, and the correlations with δ 2 H p-WM and δ 18 O p-WM have RMSE of 13.4‰ for δ 2 H n-alkane and 2.2‰ for δ 18 O ara .
A correction has been made to the Supplementary Material, Apparent Fractionation Against Climate. The corrected version is as follows:  "In addition to climate, we correlated the Ɛ app values against altitude, to test for altitude-controlled evapotranspirative enrichment. In contrast to a previous study by Polissar and Freeman (2010), no impact could be observed for δ 2 H n-alkane and δ 18 O ara , with Ɛ 2H n-C29/p, Ɛ 2H n-C31/p and Ɛ 18Oara/p being constant along our investigated transect (Supplementary The authors apologize for these errors and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.