Consistent mineral-associated organic carbon chemistry with variable erosion rates in a mountainous landscape

Xiang Wang, Adrian A Wackett, Brandy M. Toner, Kyungsoo Yoo

Research output: Contribution to journalArticlepeer-review

Abstract

Interactions between organic carbon (OC) and minerals represent a critical mechanism for stabilizing organic matter in soils. Because both mineral weathering and plant productivity are negatively affected by soil erosion, mineral-associated organic carbon (MOC) chemistry is also expected to vary with erosion intensity. Here we show that MOC chemistry, determined by carbon X-ray absorption near-edge fine structure spectroscopy (XANES), exhibits little difference across a large (10-fold) gradient in erosion-derived soil turnover times. Mineral-associated OC chemistry further fails to explain the variation in radiocarbon-based MOC turnover times. Our results suggest that soil OC longevity is largely independent of organic matter chemistry in steep mountainous landscapes where soil development is constrained by erosion.

Original languageEnglish (US)
Article number115448
JournalGeoderma
Volume405
DOIs
StatePublished - Jan 1 2022

Bibliographical note

Funding Information:
Carbon spectroscopy was performed at the Canadian Light Source (CLS) supported by the Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research. We also thank J. Dynes, T. Regier, and Z. Arthur for their assistance at the CLS’s SGM beamline and Dr. Marco Keiluweit at the University of Massachusetts Amherst for providing the XANES fitting guide. Field sampling was conducted with S. Mudd and B. Weinman. This work was funded by the National Natural Science Foundation of China (42077063) to Wang and a National Science Foundation grant to Yoo (EAR1253198).

Funding Information:
Carbon spectroscopy was performed at the Canadian Light Source (CLS) supported by the Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research. We also thank J. Dynes, T. Regier, and Z. Arthur for their assistance at the CLS's SGM beamline and Dr. Marco Keiluweit at the University of Massachusetts Amherst for providing the XANES fitting guide. Field sampling was conducted with S. Mudd and B. Weinman. This work was funded by the National Natural Science Foundation of China (42077063) to Wang and a National Science Foundation grant to Yoo (EAR1253198).

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Erosion
  • Mineral-associated organic carbon
  • Radiocarbon (C)
  • Soil organic carbon
  • Synchrotron
  • X-ray absorption near-edge fine structure spectroscopy (XANES)

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