Quantification of Lignin Degradation Products in Dissolved Organic Matter Among Three Tree Species
Date
2024-05
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
Stemflow is a major source of dissolved organic matter (DOM) into the subsoil around
a tree via preferential flow paths. Contained in the DOM matrix is soluble lignin
which is an aromatic polymer that is an important structural component of terrestrial
plants, resistant to microbial and environmental degradation and can serve as a
powerful biomarker. Numerous studies have been conducted quantifying lignin
content in DOM derived from surface waters globally, but none exist on stemflow. In
this study, samples from Liriodendron tuliprifera L. (yellow poplar), Fagus
grandifolia Ehrh (American beech), and Betula lenta L. (sweet birch) were collected
and lignin isolated by solid phase extraction for my experiments. Ultraviolet-visible
light and fluorescence spectrometry was conducted alongside high performance liquid
chromatography mass spectrometry to quantify lignin in stemflow DOM. In this study,
it was observed that normalized lignin concentrations were an order of magnitude
greater than those measured in freshwater systems demonstrating the importance of
stemflow DOM as a major source of soluble lignin into the subsoil. This study also
overlapped a large Canadian wildfire in 2023 and found some evidence that stemflow
DOM composition was affected by these wildfires.