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dc.contributor.authorBehnke, Megan
dc.contributor.authorFellman, Jason B.
dc.contributor.authorD'Amore, David V.
dc.contributor.authorGomez, S. M.
dc.contributor.authorSpencer, R. G. M.
dc.identifier.citationBehnke, M.I., Fellman, J.B., D’Amore, D.V. et al. From canopy to consumer: what makes and modifies terrestrial DOM in a temperate forest. Biogeochemistry (2022).
dc.description.abstractTo investigate how source and processing control the composition of “terrestrial” dissolved organic matter (DOM), we combine soil and tree leachates, tree DOM, laboratory bioincubations, and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry in three common landscape types (upland forest, forested wetland, and poor fen) of Southeast Alaska’s temperate rainforest. Tree (Tsuga heterophylla and Picea sitchensis) needles and bark and soil layers from each site were leached, and tree stemflow and throughfall collected to examine DOM sources. Dissolved organic carbon concentrations were as high as 167 mg CL−1 for tree DOM, suggesting tree DOM fluxes may be substantial given the hypermaritime climate of the region. Condensed aromatics contributed as much as 38% relative abundance of spruce and hemlock bark leachates suggesting coniferous trees are potential sources of condensed aromatics to surface waters. Soil leachates showed soil wetness dictates DOM composition and processing, with wetland soils producing more aromatic formulae and allowing the preservation of traditionally biolabile, aliphatic formulae. Biodegradation impacted soil and tree DOM differently, and though the majority of source-specific marker formulae were consumed for all sources, some marker formulae persisted. Tree DOM was highly biolabile (> 50%) and showed compositional convergence where processing homogenized DOM from different tree sources. In contrast, wetland and upland soil leachate DOM composition diverged and processing diversified DOM from different soil sources during bioincubations. Increasing precipitation intensity predicted with climate change in Southeast Alaska will increase tree leaching and soil DOM flushing, tightening linkages between terrestrial sources and DOM export to the coastal ocean.en_US
dc.description.sponsorshipThe authors thank Emily Whitney for her invaluable feld, laboratory, and logistical assistance and Molly Tankersley for creating Fig. 1. They are also grateful to all the helpful researchers at the National High Magnetic Field Laboratory who enabled data acquisition and processing. This work took place on the lands of the Aak’w Kwáan Tlingit. This work was supported by the National Science Foundation through an NSF Graduate Research Fellowship to MIB. A portion of this work was performed at the National High Magnetic Field Laboratory ICR User Facility, which is supported by the National Science Foundation Division of Chemistry and Division of Materials Research through DMR-1644779 and the State of Florida. Conficts of interest/ Competing interests: The authors have no conficts of interests to declare.en_US
dc.subjectSoutheast Alaskaen_US
dc.subjectDissolved organic matteren_US
dc.subjectFT-ICR MSen_US
dc.subjectTree DOMen_US
dc.subjectMicrobial processingen_US
dc.subjectCondensed aromaticsen_US
dc.titleFrom canopy to consumer: what makes and modifes terrestrial DOM in a temperate foresten_US

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  • Behnke, Megan
    Postdoctoral Researcher, Alaska Coastal Rainforest Center

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