Molecular shifts in dissolved organic matter along a burn severity continuum for common land cover types in the Pacific Northwest, USA.

Autor: Roebuck JA Jr; Biological Sciences Division, Pacific Northwest National Laboratory, Sequim, WA, USA., Grieger S; Biological Sciences Division, Pacific Northwest National Laboratory, Sequim, WA, USA., Barnes ME; Biological Sciences Division, Pacific Northwest National Laboratory, Sequim, WA, USA., Gillespie X; Biological Sciences Division, Pacific Northwest National Laboratory, Sequim, WA, USA., Bladon KD; College of Forestry, Oregon State University, Corvallis, OR, USA., Bailey JD; College of Forestry, Oregon State University, Corvallis, OR, USA., Graham EB; Biological Sciences Division, Pacific Northwest National Laboratory, Sequim, WA, USA; School of Biological Sciences, Washington State University, Pullman, WA, USA., Chu R; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA., Kew W; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA., Scheibe TD; Pacific Northwest National Laboratory, Richland, WA, USA., Myers-Pigg AN; Biological Sciences Division, Pacific Northwest National Laboratory, Sequim, WA, USA; Department of Environmental Sciences, College of Natural Sciences & Mathematics, University of Toledo, Toledo, OH, USA. Electronic address: allison.myers-pigg@pnnl.gov.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 Dec 14; Vol. 958, pp. 178040. Date of Electronic Publication: 2024 Dec 14.
DOI: 10.1016/j.scitotenv.2024.178040
Abstrakt: Increasing wildfire severity is of growing concern in the western United States, with consequences for the production, composition, and mobilization of dissolved organic matter (DOM) from terrestrial to aquatic systems. Our current understanding of wildfire impacted DOM (often termed pyrogenic DOM) composition is largely built from temperature-based studies that can be difficult to extrapolate to field conditions, which are often defined by 'burn severity', or the post-wildfire impact observed at a site. Thus, burn severity can encapsulate a broader range of fire and environmental conditions not exclusive to temperature. Biogeochemical studies that describe DOM along burn severity continuums remain limited but are needed to better link DOM composition with field conditions post-fire. In this study, we addressed this need with an experimental open air burn simulation that generated chars from vegetation representative of major land cover types in the western United States. The chars were leached to simulate DOM mobilization potential. The DOM composition was characterized by ultra-high resolution mass spectrometry (HR-MS) and UV/VIS absorbance and fluorescence. Our results indicated that the shifts of DOM production and composition along a burn-severity gradient depends on the land cover type that was burned, with the degree of change dependent on the composition of the starting parent vegetation material. Fluorescence signatures indicated a strong convergence across land cover types to more aromatic DOM with increasing severity, while HR-MS indicated an increase in the production of aromatic nitrogen containing DOM with increasing severity. Results from this study enhance our ability to describe DOM composition in a framework that can be more directly related with field and remote-sensing based metrics.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier B.V.)
Databáze: MEDLINE
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