气候变化领域集成服务门户(CCPortal): Evidence linking calcium to increased organo-mineral association in soils

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DOI	10.1007/s10533-021-00779-7
	Evidence linking calcium to increased organo-mineral association in soils
	Rowley M.C.; Grand S.; Spangenberg J.E.; Verrecchia E.P.
发表日期	2021
ISSN	1682563
起始页码	223
结束页码	241
卷号	153 期号:3
英文摘要	Geochemical indicators are emerging as important predictors of soil organic carbon (SOC) dynamics, but evidence concerning the role of calcium (Ca) is scarce. This study investigates the role of Ca prevalence in SOC accumulation by comparing otherwise similar sites with (CaCO3-bearing) or without carbonates (CaCO3-free). We measured the SOC content and indicators of organic matter quality (C stable isotope composition, expressed as δ13C values, and thermal stability) in bulk soil samples. We then used sequential sonication and density fractionation (DF) to separate two occluded pools from free and mineral-associated SOC. The SOC content, mass, and δ13C values were determined in all the fractions. X-ray photoelectron spectroscopy was used to investigate the surface chemistry of selected fractions. Our hypothesis was that occlusion would be more prevalent at the CaCO3-bearing site due to the influence of Ca on aggregation, inhibiting oxidative transformation, and preserving lower δ13C values. Bulk SOC content was twice as high in the CaCO3-bearing profiles, which also had lower bulk δ13C values, and more occluded SOC. Yet, contrary to our hypothesis, occlusion only accounted for a small proportion of total SOC (< 10%). Instead, it was the heavy fraction (HF), containing mineral-associated organic C, which accounted for the majority of total SOC and for the lower bulk δ13C values. Overall, an increased Ca prevalence was associated with a near-doubling of mineral-associated SOC content. Future investigations should now aim to isolate Ca-mediated complexation processes that increase organo-mineral association and preserve organic matter with lower δ13C values. © 2021, The Author(s).
英文关键词	Carbon stable isotopes; Density fractionation; Rock-Eval® pyrolysis; Soil organic carbon; X-ray photoelectron spectroscopy
语种	英语
来源期刊	Biogeochemistry
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184606
作者单位	Institut des dynamiques de la surface terrestre (IDYST), Université de Lausanne, Lausanne, Switzerland; Energy and Geosciences Division, Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
推荐引用方式 GB/T 7714	Rowley M.C.,Grand S.,Spangenberg J.E.,et al. Evidence linking calcium to increased organo-mineral association in soils[J],2021,153(3).
APA	Rowley M.C.,Grand S.,Spangenberg J.E.,&Verrecchia E.P..(2021).Evidence linking calcium to increased organo-mineral association in soils.Biogeochemistry,153(3).
MLA	Rowley M.C.,et al."Evidence linking calcium to increased organo-mineral association in soils".Biogeochemistry 153.3(2021).