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Title: Dissolved organic matter transport reflects hillslope to stream connectivity during snowmelt in a montane catchment

Dissolved organic matter (DOM) transport is a key biogeochemical linkage across the terrestrial-aquatic interface in headwater catchments, and quantifying the biological and hydrological controls on DOM composition provides insight into DOM cycling at the catchment scale. In this paper, we evaluated the mobility of DOM components during snowmelt in a montane, semiarid catchment. DOM composition was evaluated on a near-daily basis within the soil and the stream during snowmelt, and was compared to groundwater samples using a site-specific parallel factor analysis (PARAFAC) model derived from soil extracts. The fluorescent component loadings in the interstitial soil water and in the groundwater were significantly different and did not temporally change during snowmelt. In the stream, a transition occurred during snowmelt from fluorescent DOM with higher contributions of amino acid-like components indicative of groundwater to higher humic-like contributions indicative of soil water. Furthermore, we identified a humic-like fluorescent component in the soil water and the stream that is typically only observed in extracted water soluble organic matter from soil which may suggest hillslope to stream connectivity over very short time scales. Qualitative interpretations of changes in stream fluorescent DOM were supported by two end-member mixing analyses of conservative tracers. After normalizing fluorescent DOMmore » loadings for dissolved organic carbon (DOC) concentration, we found that the peak in DOC concentration in the stream was driven by the nonfluorescent fraction of DOM. Finally, this study demonstrated how PARAFAC analysis can be used to refine our conceptual models of runoff generation sources, as well as provide a more detailed understanding of stream chemistry dynamics.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3]
  1. Univ. of Colorado, Boulder, CO (United States). Inst. of Arctic and Alpine Research
  2. Univ. of Colorado, Boulder, CO (United States). Inst. of Arctic and Alpine Research; Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics
  3. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics
Publication Date:
Grant/Contract Number:
SC0006968; EAR-0724960
Type:
Accepted Manuscript
Journal Name:
Water Resources Research
Additional Journal Information:
Journal Volume: 52; Journal Issue: 6; Journal ID: ISSN 0043-1397
Publisher:
American Geophysical Union (AGU)
Research Org:
Univ. of Colorado, Boulder, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; dissolved organic matter; fluorescence; PARAFAC; montane; snowmelt; ecohydrology
OSTI Identifier:
1469170

Burns, Margaret A., Barnard, Holly R., Gabor, Rachel S., McKnight, Diane M., and Brooks, Paul D.. Dissolved organic matter transport reflects hillslope to stream connectivity during snowmelt in a montane catchment. United States: N. p., Web. doi:10.1002/2015WR017878.
Burns, Margaret A., Barnard, Holly R., Gabor, Rachel S., McKnight, Diane M., & Brooks, Paul D.. Dissolved organic matter transport reflects hillslope to stream connectivity during snowmelt in a montane catchment. United States. doi:10.1002/2015WR017878.
Burns, Margaret A., Barnard, Holly R., Gabor, Rachel S., McKnight, Diane M., and Brooks, Paul D.. 2016. "Dissolved organic matter transport reflects hillslope to stream connectivity during snowmelt in a montane catchment". United States. doi:10.1002/2015WR017878. https://www.osti.gov/servlets/purl/1469170.
@article{osti_1469170,
title = {Dissolved organic matter transport reflects hillslope to stream connectivity during snowmelt in a montane catchment},
author = {Burns, Margaret A. and Barnard, Holly R. and Gabor, Rachel S. and McKnight, Diane M. and Brooks, Paul D.},
abstractNote = {Dissolved organic matter (DOM) transport is a key biogeochemical linkage across the terrestrial-aquatic interface in headwater catchments, and quantifying the biological and hydrological controls on DOM composition provides insight into DOM cycling at the catchment scale. In this paper, we evaluated the mobility of DOM components during snowmelt in a montane, semiarid catchment. DOM composition was evaluated on a near-daily basis within the soil and the stream during snowmelt, and was compared to groundwater samples using a site-specific parallel factor analysis (PARAFAC) model derived from soil extracts. The fluorescent component loadings in the interstitial soil water and in the groundwater were significantly different and did not temporally change during snowmelt. In the stream, a transition occurred during snowmelt from fluorescent DOM with higher contributions of amino acid-like components indicative of groundwater to higher humic-like contributions indicative of soil water. Furthermore, we identified a humic-like fluorescent component in the soil water and the stream that is typically only observed in extracted water soluble organic matter from soil which may suggest hillslope to stream connectivity over very short time scales. Qualitative interpretations of changes in stream fluorescent DOM were supported by two end-member mixing analyses of conservative tracers. After normalizing fluorescent DOM loadings for dissolved organic carbon (DOC) concentration, we found that the peak in DOC concentration in the stream was driven by the nonfluorescent fraction of DOM. Finally, this study demonstrated how PARAFAC analysis can be used to refine our conceptual models of runoff generation sources, as well as provide a more detailed understanding of stream chemistry dynamics.},
doi = {10.1002/2015WR017878},
journal = {Water Resources Research},
number = 6,
volume = 52,
place = {United States},
year = {2016},
month = {6}
}