TY - JOUR
T1 - Stability of biomass-derived black carbon in soils
AU - Liang, Biqing
AU - Lehmann, Johannes
AU - Solomon, Dawit
AU - Sohi, Saran
AU - Thies, Janice E.
AU - Skjemstad, Jan O.
AU - Luizão, Flavio J.
AU - Engelhard, Mark H.
AU - Neves, Eduardo G.
AU - Wirick, Sue
N1 - Funding Information:
This project was funded by the Division of Environmental Biology of the National Science Foundation under contract DEB-0425995. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. The NEXAFS spectra were obtained at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, a DOE supported facility at the beamline X-1A1 developed by the group of Janos Kirz and Chris Jacobsen at SUNY Stony Brook, with support from the New York State Office of Science and Technology Academic Research and NASA’s Discovery Data Analysis and Exobiology programs. The XPS analyses were performed in the Environmental Molecular and Sciences Laboratory, Pacific Northwest National Laboratory, a national scientific user facility sponsored by the Department of Energy (DoE), USA. Rothamsted Research receives grant-aided support from the UK Biotechnology and Biological Sciences Research Council. Many thanks to Jeffrey A. Baldock for insightful advice, to James Kinyangi for technical discussion about NEXAFS analysis, to Helen Yates for the soil fractionation, to Fernando Costa and Manuel Arroyo-Kalin for help with sampling, and to Yuanming Zhang for invaluable help with sectioning.
PY - 2008/12/15
Y1 - 2008/12/15
N2 - Black carbon (BC) may play an important role in the global C budget, due to its potential to act as a significant sink of atmospheric CO2. In order to fully evaluate the influence of BC on the global C cycle, an understanding of the stability of BC is required. The biochemical stability of BC was assessed in a chronosequence of high-BC-containing Anthrosols from the central Amazon, Brazil, using a range of spectroscopic and biological methods. Results revealed that the Anthrosols had 61-80% lower (P < 0.05) CO2 evolution per unit C over 532 days compared to their respective adjacent soils with low BC contents. No significant (P > 0.05) difference in CO2 respiration per unit C was observed between Anthrosols with contrasting ages of BC (600-8700 years BP) and soil textures (0.3-36% clay). Similarly, the molecular composition of the core regions of micrometer-sized BC particles quantified by synchrotron-based Near-Edge X-ray Fine Structure (NEXAFS) spectroscopy coupled to Scanning Transmission X-ray Microscopy (STXM) remained similar regardless of their ages and closely resembled the spectral characteristics of fresh BC. BC decomposed extremely slowly to an extent that it was not possible to detect chemical changes between youngest and oldest samples, as also confirmed by X-ray Photoelectron Spectroscopy (XPS). Deconvolution of NEXAFS spectra revealed greater oxidation on the surfaces of BC particles with little penetration into the core of the particles. The similar C mineralization between different BC-rich soils regardless of soil texture underpins the importance of chemical recalcitrance for the stability of BC, in contrast to adjacent soils which showed the highest mineralization in the sandiest soil. However, the BC-rich Anthrosols had higher proportions (72-90%) of C in the more stable organo-mineral fraction than BC-poor adjacent soils (2-70%), suggesting some degree of physical stabilization.
AB - Black carbon (BC) may play an important role in the global C budget, due to its potential to act as a significant sink of atmospheric CO2. In order to fully evaluate the influence of BC on the global C cycle, an understanding of the stability of BC is required. The biochemical stability of BC was assessed in a chronosequence of high-BC-containing Anthrosols from the central Amazon, Brazil, using a range of spectroscopic and biological methods. Results revealed that the Anthrosols had 61-80% lower (P < 0.05) CO2 evolution per unit C over 532 days compared to their respective adjacent soils with low BC contents. No significant (P > 0.05) difference in CO2 respiration per unit C was observed between Anthrosols with contrasting ages of BC (600-8700 years BP) and soil textures (0.3-36% clay). Similarly, the molecular composition of the core regions of micrometer-sized BC particles quantified by synchrotron-based Near-Edge X-ray Fine Structure (NEXAFS) spectroscopy coupled to Scanning Transmission X-ray Microscopy (STXM) remained similar regardless of their ages and closely resembled the spectral characteristics of fresh BC. BC decomposed extremely slowly to an extent that it was not possible to detect chemical changes between youngest and oldest samples, as also confirmed by X-ray Photoelectron Spectroscopy (XPS). Deconvolution of NEXAFS spectra revealed greater oxidation on the surfaces of BC particles with little penetration into the core of the particles. The similar C mineralization between different BC-rich soils regardless of soil texture underpins the importance of chemical recalcitrance for the stability of BC, in contrast to adjacent soils which showed the highest mineralization in the sandiest soil. However, the BC-rich Anthrosols had higher proportions (72-90%) of C in the more stable organo-mineral fraction than BC-poor adjacent soils (2-70%), suggesting some degree of physical stabilization.
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U2 - 10.1016/j.gca.2008.09.028
DO - 10.1016/j.gca.2008.09.028
M3 - Article
AN - SCOPUS:56549112316
SN - 0016-7037
VL - 72
SP - 6069
EP - 6078
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 24
ER -