University of Oulu

Fellman, J. B., Hood, E., Behnke, M. I., Welker, J. M., & Spencer, R. G. M. (2020). Stormflows drive stream carbon concentration, speciation, and dissolved organic matter composition in coastal temperate rainforest watersheds. Journal of Geophysical Research: Biogeosciences, 125, e2020JG005804. https://doi.org/10.1029/2020JG005804

Stormflows drive stream carbon concentration, speciation, and dissolved organic matter composition in coastal temperate rainforest watersheds

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Author: Fellman, Jason B.1; Hood, Eran1; Behnke, Megan I.2;
Organizations: 1Department of Natural Sciences and Alaska Coastal Rainforest Center, University of Alaska Southeast, Juneau, AK, USA
2Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL, USA
3Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, USA
4Department of Ecology and Genetics, University of Oulu & UArctic, Oulu, Finland
Format: article
Version: published version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe202102023528
Language: English
Published: American Geophysical Union, 2020
Publish Date: 2021-03-09
Description:

Abstract

Stream water carbon concentrations can be highly dynamic on the time scales of both individual storm events and seasonal hydroclimatic shifts. We collected stream water daily over a 6‐day storm from three headwater subcatchments of varying landcover (poor fen, forested wetland, and upland forest) and the catchment outlet to evaluate how precipitation events impact the concentration and speciation of carbon (organic vs. inorganic) as well as the composition of dissolved organic matter (DOM) exported laterally from coastal temperate rainforest catchments. Dissolved and particulate organic carbon concentrations increased during the storm at all sites, while dissolved inorganic carbon concentrations were diluted during peak flows. These results highlight the importance of quantifying all forms of lateral carbon export when evaluating the role of storms in catchment‐scale carbon cycling. Isotopic hydrograph separation using stream water δ¹⁸O showed that percent new water was significantly related to carbon concentration and form providing a clear link between stream water sources (i.e., recent event water) and soil carbon source areas that become connected to surface water during storms. Furthermore, ultrahigh‐resolution mass spectrometry showed that stream water DOM exported from the upland forest contained the greatest molecular diversity of the three landscape types and had the largest changes in composition over the storm suggesting that the wetland‐dominated subcatchments were less compositionally diverse with regard to soil DOM pools active during the storm. Overall, this study provides insight into hydro‐biogeochemical drivers that control lateral carbon export from forested catchments in a region where an increasing fraction of precipitation is falling as rain.

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Series: Journal of geophysical research. Biogeosciences
ISSN: 2169-8953
ISSN-E: 2169-8961
ISSN-L: 2169-8953
Volume: 125
Issue: 9
Article number: e2020JG005804
DOI: 10.1029/2020JG005804
OADOI: https://oadoi.org/10.1029/2020JG005804
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Subjects:
Funding: This study received support from the University of Alaska Faculty Initiative Fund. 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 through DMR‐1644779 and DMR‐1157490 and the State of Florida. J. F. and E. H. also received support from National Science Foundation (NSF) under Award OIA‐1753748.
Copyright information: ©2020. American Geophysical Union. All Rights Reserved.