Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 13, issue 17
Biogeosciences, 13, 5057–5064, 2016
https://doi.org/10.5194/bg-13-5057-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 13, 5057–5064, 2016
https://doi.org/10.5194/bg-13-5057-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 13 Sep 2016

Research article | 13 Sep 2016

Temperature exerts no influence on organic matter δ13C of surface soil along the 400 mm isopleth of mean annual precipitation in China

Yufu Jia, Guoan Wang, Qiqi Tan, and Zixun Chen Yufu Jia et al.
  • College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China

Abstract. Soil organic carbon is the largest pool of carbon in the terrestrial ecosystem, and its isotopic composition is affected by a number of factors. However, the influence of environmental factors, especially temperature, on soil organic carbon isotope values (δ13CSOM) is poorly constrained. This impedes the application of the variability of organic carbon isotopes to reconstructions of paleoclimate, paleoecology, and global carbon cycling. Given the considerable temperature gradient along the 400 mm isohyet (isopleth of mean annual precipitation – MAP) in China, this isohyet provides ideal experimental sites for studying the influence of temperature on soil organic carbon isotopes. In this study, the effect of temperature on surface soil δ13C was assessed by a comprehensive investigation of 27 sites across a temperature gradient along the isohyet. Results demonstrate that temperature does not play a role in soil δ13C. This suggests that organic carbon isotopes in sediments cannot be used for paleotemperature reconstruction and that the effect of temperature on organic carbon isotopes can be neglected in the reconstruction of paleoclimate and paleovegetation. Multiple regressions with MAT (mean annual temperature), MAP, altitude, latitude, and longitude as independent variables and δ13CSOM as the dependent variable show that these five environmental factors together account for only 9 % of soil δ13C variance. However, one-way ANOVA analyses suggest that soil type and vegetation type are significant factors influencing soil δ13C. Multiple regressions, in which the five aforementioned environmental factors were taken as quantitative variables, and vegetation type, soil type based on the Chinese Soil Taxonomy, and World Reference Base (WRB) soil type were separately used as dummy variables, show that 36.2, 37.4, and 29.7 %, respectively, of the variability in soil δ13C are explained. Compared to the multiple regressions in which only quantitative environmental variables were introduced, the multiple regressions in which soil and vegetation were also introduced explain more of the isotopic variance, suggesting that soil type and vegetation type exert a significant influence on δ13CSOM.

Publications Copernicus
Download
Short summary
Soil organic carbon can be used for climate reconstruction and carbon cycle study. This work assessed the effect of temperature on surface soil δ13C by an investigation from 27 sites across a temperature gradient along an isohyet. This study shows that soil type and vegetation type had influences on soil δ13C, while temperature was not related to soil δ13C. This suggests that organic carbon isotopes in sediments cannot be used for the paleotemperature reconstruction.
Soil organic carbon can be used for climate reconstruction and carbon cycle study. This work...
Citation