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| Titel |
Concentrations and fluxes of dissolved organic carbon in runoff from a forested catchment: insights from high frequency measurements |
| VerfasserIn |
S. Strohmeier, K.-H. Knorr, M. Reichert, S. Frei, J. H. Fleckenstein, S. Peiffer, E. Matzner |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 2 ; Nr. 10, no. 2 (2013-02-08), S.905-916 |
| Datensatznummer |
250017508
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| Publikation (Nr.) |
 copernicus.org/bg-10-905-2013.pdf |
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| Zusammenfassung |
Concentrations of dissolved organic carbon (DOC) in runoff from catchments
are often subject to substantial short-term variations. The aim of this
study was to identify the compartmental sources of DOC in a forested
catchment and the causes for short-term variations in runoff. Furthermore,
we investigated the implication of short-term variations for the calculation
of annual runoff fluxes. High frequency measurements (30 min intervals)
of DOC in runoff, of discharge and groundwater table were conducted for one
year in the 4.2 km2 forested Lehstenbach catchment, Germany. Riparian
wetland soils represent about 30% of the catchment area. The quality of
DOC was investigated by three dimensional fluorescence excitation-emission
matrices in samples taken from runoff, deep groundwater and shallow
groundwater from the riparian wetland soils. The concentrations of DOC in
runoff were highly variable at an hourly to daily time scale, ranging from
2.6 mg L−1 to 34 mg L−1 with an annual average of 9.2 mg L−1.
The concentrations were positively related to discharge, with a counter
clockwise hysteresis. Relations of DOC to discharge were steeper and the
degree of hysteresis larger in the summer/fall than in the winter/spring
period. Dynamics of groundwater table, discharge, DOC concentrations and DOC
quality parameters indicated that DOC in runoff originated mainly from the
riparian wetland soils, both under low and high flow conditions. The annual
export of DOC from the catchment was 84 kg C ha−1 yr−1 when
calculated from the high frequency measurements. If the annual export was
calculated by simulated samplings of >2 days intervals
substantial deviations resulted.
Predicted changes in precipitation and discharge patterns as well as
generally increasing temperatures likely will cause raising DOC exports from
this catchment. |
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