Optical properties of dissolved organic matter in throughfall and stemflow vary across tree species and season in a temperate headwater forest

Biogeochemistry
By: , and 

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Abstract

Tree-derived dissolved organic matter (DOM) comprises a significant carbon flux within forested watersheds. Few studies have assessed the optical properties of tree-derived DOM. To increase understanding of the factors controlling tree-derived DOM quality, we measured DOM optical properties, dissolved organic carbon (DOC) and calcium concentrations in throughfall and stemflow for 17 individual rain events during summer and fall in a temperate deciduous forest in Vermont, United States. DOC and calcium fluxes in throughfall and stemflow were enriched on average 4 to 70 times incident fluxes in rain. A multiway model was developed using absorbance and fluorescence spectroscopy to further characterize DOM optical properties. Throughfall contained a higher percentage of protein-like DOM fluorescence than stemflow while stemflow was characterized by a higher percentage of humic-like DOM fluorescence. DOM absorbance spectral slopes in yellow birch (Betula alleghaniensis) stemflow were significantly higher than in sugar maple (Acer saccharum) stemflow. DOM optical metrics were not influenced by rainfall volume, but percent protein-like fluorescence increased in throughfall during autumn when leaves senesced. Given the potential influence of tree-derived DOM fluxes on receiving soils and downstream ecosystems, future modeling of DOM transport and soil biogeochemistry should represent the influence of differing DOM quality in throughfall and stemflow across tree species and seasons.

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Publication type Article
Publication Subtype Journal Article
Title Optical properties of dissolved organic matter in throughfall and stemflow vary across tree species and season in a temperate headwater forest
Series title Biogeochemistry
DOI 10.1007/s10533-022-00985-x
Volume 164
Year Published 2023
Language English
Publisher Springer Link
Contributing office(s) New England Water Science Center
Description 20 p.
First page 53
Last page 72
Country United States
State Vermont
Other Geospatial Sleepers River Research Watershed
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