Soil n-alkane δ13C along a mountain slope as an integrator of altitude effect on plant species δ13C

Authors

  • Kai Wei,

    1. CAS Key lab of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
    2. Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
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  • Guodong Jia

    1. CAS Key lab of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
    2. State Key Lab of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
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Abstract

[1] Carbon isotopic compositions of leaf wax-derived n-alkanes (δ13Cwax) and bulk organic matter (δ13CSOM) in surface soils from ca. 1000 to 3800 m above sea level along Mount Gongga, China were investigated for their altitudinal variations. There is a breakpoint, suggesting a precipitation threshold, at 2050 m in both δ13Cwax and δ13CSOM trends. Above the threshold, δ13Cwax and δ13CSOM increase in a similar pattern of the average species-level response to altitude reported from various humid mountainous areas. However, a significant decreasing trend with altitude occurs below the threshold, within which climate changes upward from arid to humid, consistent with plant foliar δ13C response to precipitation at water-limited areas. Because δ13Cwax and δ13CSOM naturally integrate plant species and time, this work demonstrates that the altitude-induced environmental impact on plant species-level δ13C has been conveyed to soils, and that the species-level δ13C could be linearly scaled up to the community level.

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