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| Titel |
DOC sources and DOC transport pathways in a small headwater catchment as revealed by carbon isotope fluctuation during storm events |
| VerfasserIn |
T. Lambert, A.-C. Pierson-Wickmann, G. Gruau, A. Jaffrézic, P. Petitjean, J. N. Thibault, L. Jeanneau |
| 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 ; 11, no. 11 ; Nr. 11, no. 11 (2014-06-11), S.3043-3056 |
| Datensatznummer |
250117452
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| Publikation (Nr.) |
 copernicus.org/bg-11-3043-2014.pdf |
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| Zusammenfassung |
| Monitoring the isotopic composition (δ13CDOC) of dissolved
organic carbon (DOC) during flood events can be helpful for locating DOC
sources in catchments and quantifying their relative contribution to stream
DOC flux. High-resolution (< hourly basis) δ13CDOC
data were obtained during six successive storm events occurring during the
high-flow period in a small headwater catchment in western France.
Intra-storm δ13CDOC values exhibit a marked temporal
variability, with some storms showing large variations (> 2 ‰), and others yielding a very restricted range of
values (< 1 ‰). Comparison of these results with
previously published data shows that the range of intra-storm δ13CDOC values closely reflects the temporal and spatial variation
in δ13CDOC observed in the riparian soils of this
catchment during the same period. Using δ13CDOC data in
conjunction with hydrometric monitoring and an end-member mixing approach (EMMA),
we show that (i) > 80% of the stream DOC flux flows through
the most superficial soil horizons of the riparian domain and (ii) the
riparian soil DOC flux is comprised of DOC coming ultimately from both
riparian and upland domains. Based on its δ13C fingerprint, we
find that the upland DOC contribution decreases from ca.~30% of the
stream DOC flux at the beginning of the high-flow period to < 10% later in this period. Overall, upland domains contribute significantly to
stream DOC export, but act as a size-limited reservoir, whereas soils in the
wetland domains act as a near-infinite reservoir. Through this study, we
show that δ13CDOC provides a powerful tool for tracing DOC
sources and DOC transport mechanisms in headwater catchments, having a
high-resolution assessment of temporal and spatial variability. |
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