Riparian Zone Influence on Stream Water Dissolved Organic Carbon Concentrations at the Swedish Integrated Monitoring Sites
Short-term variability in stream water dissolved organic carbon (DOC) concentrations is controlled by hydrology, climate and atmospheric deposition. Using the Riparian flow-concentration Integration Model (RIM), we evaluated factors controlling stream water DOC in the Swedish Integrated Monitoring (IM) catchments by separating out hydrological effects on stream DOC dynamics. Model residuals were correlated with climate and deposition-related drivers. DOC was most strongly correlated to water flow in the northern catchment (Gammtratten). The southern Aneboda and Kindla catchments had pronounced seasonal DOC signals, which correlated weakly to flow. DOC concentrations at Gårdsjön increased, potentially in response to declining acid deposition. Soil temperature correlated strongly with model residuals at all sites. Incorporating soil temperature in RIM improved model performance substantially (20–62% lower median absolute error). According to the simulations, the RIM conceptualization of riparian processes explains between 36% (Kindla) and 61% (Aneboda) of the DOC dynamics at the IM sites.
KeywordsDOC RIM Modeling Riparian zone Organic carbon Soil temperature
The Swedish Integrated Monitoring program has been funded by the Swedish Environmental Protection Agency. This work would not have been possible without the efforts of all the people who collected and analyzed samples from the IM sites, and those who maintained the data archive. MNF was funded by the Mistra FutureForests programme. Financial support for JT was provided by the Swedish Environmental Protection Agency programme CLEO, the Swedish University of Agricultural Sciences and the Swedish Meteorological and Hydrological Institute.
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