Characterization and Biodegradation of Water-Soluble Biomarkers and Organic Carbon Extracted From Low Temperature Chars

Document Type

Article

Publication Date

3-1-2013

Department

Geography and Geology

School

Biological, Environmental, and Earth Sciences

Abstract

This study demonstrates that wildfires/biomass combustion may be an important source of labile pyrogenic water-soluble organic matter (Py-WSOM) in aquatic systems. Spectroscopic analysis (solid char and Py-WSOM) with Fourier transform infrared spectroscopy (FTIR) indicated that the Py-WSOM extracted from two low temperature chars (one wood, one grass) was dominated by polar moieties (-OH and C-O) derived from depolymerization and fragmentation of lignocellulose. Incubation experiments under aerobic conditions with unsterilized river water suggested that Py-WSOM and associated biomarkers may have a turnover rate of the order of weeks to months, consistent with mixing and transport conditions of riverine systems. For example, pyrogenic dissolved organic carbon (Py-DOC) had a half-life of 30-40 days. Turnover rate for the combustion biomarkers was shorter, with levoglucosan and free lignin phenols having a half life around 3-4 days and polymeric lignin components 13-14 days. The latter observations contradict earlier studies of the biodegradation of dissolved lignin and point to the need for re-assessment of lignin degradation kinetics in well-mixed riverine systems, particularly when such lignin components are derived from thermally altered plant material that may exist in a form more labile than that in highly processed riverine DOM. (C) 2013 Elsevier Ltd. All rights reserved.

Publication Title

Organic Geochemistry

Volume

56

First Page

111

Last Page

119

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