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TitleSources and flowpaths of dissolved organic carbon during storms in two forested watersheds of the Precambrian Shield
AuthorHinton, M J; Schiff, S L; English, M C
SourceBiogeochemistry vol. 41, 1998 p. 175-197,
Alt SeriesGeological Survey of Canada, Contribution Series 25895
PublisherSpringer Nature
Mediapaper; on-line; digital
File formatpdf
AreaHarp Lake
Lat/Long WENS -79.2500 -79.0000 45.5000 45.2500
Subjectsenvironmental geology; hydrogeology; soils science; watersheds; organic carbon; runoff; streams; groundwater flow; water table; hydrologic environment; wetlands; Precambrian Shield; carbon cycling; forested catchments; nutrient export; storm runoff; dissolved organic carbon; riparian water table
Illustrationsgraphs; histograms; tables
AbstractDissolved organic carbon (DOC) concentrations and export were studied in two small catchments in central Ontario to examine DOC sources and to assess the hypothesis that organic matter adjacent to the stream is a significant contributor of DOC during storms. Different DOC dynamics and exports were observed according to the depth of the riparian water table. In Harp 4-21, riparian flowpaths were predominantly through A and upper B soil horizons and riparian soils contributed between 73 and 84% of the stream DOC export during an autumn storm. In Harp 3A, riparian flowpaths were predominantly through lower B horizons. Consequently, riparian soils were less important and hillslopes contributed more than 50% of the stream DOC export in subcatchments without wetlands during storms. Wetlands and adjacent soils contributed significantly to DOC export in Harp 3A; 8% of the total catchment area exported 32 to 46% of the storm runoff DOC. DOC export dynamics in wetlands and riparian soils were distinctly different. In wetlands, transport was affected by leaching and flushing of DOC at the wetland surface leading to lower DOC concentrations with successive storms. In riparian soils, groundwater flowpaths were more important and stronger positive relationships between discharge and DOC concentration were observed. Precipitation, throughfall and stemflow were minor sources of stream DOC during storms and contributed less than 20% of the total export.