HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Liang, B. Articles by Neves, E. G. Search for Related Content PubMed Articles by Liang, B. Articles by Neves, E. G. Agricola Articles by Liang, B. Articles by Neves, E. G. Related Collections Soil Fertility and Productivity Biogeochemical Processes Fire

Soil Chemistry

Black Carbon Increases Cation Exchange Capacity in Soils

^a Dep. of Crop and Soil Sciences, Cornell Univ., Ithaca, NY 14853, USA
^b CSIRO Land and Water, Glen Osmond SA 5064, Australia
^c Instituto Nacional de Pesquisa da Amazônia (INPA), 69011-970 Manaus, Brazil
^d (deceased), Dep. of Anthropology, Univ. of Vermont, Burlington, VT, 05405 USA
^e Museu de Arqueologia e Etnologia, Universidade de São Paulo, Sao Paulo, SP, 05508-900, Brazil

^* Corresponding author (CL273{at}cornell.edu)

In Memory of James Petersen

Dr. James Petersen was killed during an armed robbery while doing research near Manaus, Brazil, on 13 Aug. 2005. Dr. Petersen was associate professor and chair of the Anthropology Department at University of Vermont. We will miss him as a valued colleague and good friend.

Black Carbon (BC) may significantly affect nutrient retention and play a key role in a wide range of biogeochemical processes in soils, especially for nutrient cycling. Anthrosols from the Brazilian Amazon (ages between 600 and 8700 yr BP) with high contents of biomass-derived BC had greater potential cation exchange capacity (CEC measured at pH 7) per unit organic C than adjacent soils with low BC contents. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy coupled with scanning transmission X-ray microscopy (STXM) techniques explained the source of the higher surface charge of BC compared with non-BC by mapping cross-sectional areas of BC particles with diameters of 10 to 50 µm for C forms. The largest cross-sectional areas consisted of highly aromatic or only slightly oxidized organic C most likely originating from the BC itself with a characteristic peak at 286.1 eV, which could not be found in humic substance extracts, bacteria or fungi. Oxidation significantly increased from the core of BC particles to their surfaces as shown by the ratio of carboxyl-C/aromatic-C. Spotted and non-continuous distribution patterns of highly oxidized C functional groups with distinctly different chemical signatures on BC particle surfaces (peak shift at 286.1 eV to a higher energy of 286.7 eV) indicated that non-BC may be adsorbed on the surfaces of BC particles creating highly oxidized surface. As a consequence of both oxidation of the BC particles themselves and adsorption of organic matter to BC surfaces, the charge density (potential CEC per unit surface area) was greater in BC-rich Anthrosols than adjacent soils. Additionally, a high specific surface area was attributable to the presence of BC, which may contribute to the high CEC found in soils that are rich in BC.

Abbreviations: ACU, Açutuba • BC, black carbon • CEC, cation exchange capacity • DS, Donna Stella • HAT, Hatahara • LG, Lago Grande • NEXAFS, near edge X-ray absorption fine structure • NMR, nuclear magnetic resonance • SSA, specific surface area • SOM, soil organic matter • STXM, scanning transmission X-ray microscopy