Can functional group composition of alkaline isolates from black carbon-rich soils be identified on a sub-100nm scale?

Autor: Eduardo Fausto de Almeida Neves, Sue Wirick, Biqing Liang, Dawit Solomon, Johannes Lehmann, Karen Heymann
Rok vydání: 2014
Předmět:
Zdroj: Geoderma. :163-169
ISSN: 0016-7061
DOI: 10.1016/j.geoderma.2014.07.011
Popis: Objectives Alkaline extracts from soils generate operationally-defined isolates that are referred to as “humic substances” but may not relate to a distinct molecular structure within the soil organic matter (SOM) matrix. This study examines whether alkaline extracts from black carbon (BC) rich soils can be identified on a fine spatial scale. Methods We related the functional group composition of alkaline extracts derived from BC-rich soils using Scanning Transmission X-ray Microscopy (STXM) coupled with near-edge X-ray absorption fine- structure (NEXAFS) spectroscopy to the spatial composition of a BC-rich soil microaggregate at a scale of Results Using principal component analysis, we were unable to obtain a good fit (RMS Conclusions Our results suggest that a distinct component class similar to alkaline extracted materials, often referred to as “black humic substances”, is not present in SOM on a fine spatial scale. Rather, alkaline extracts of BC-rich soils reflect the mixture of various materials at different stages of decomposition.
Databáze: OpenAIRE
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