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| Titel |
Detecting flow processes in peatlands using Li isotopes |
| VerfasserIn |
Philippe Négrel, Martin Sanda, Romain Millot, Alena Kulasova |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048840
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| Zusammenfassung |
| Mountainous fens are important hydrological components of the headwater catchments in
Jizera Mountains, (the Czech Republic). Experimental catchment UhlíÅská (1.78 km2) is
formed by Paleozoic crystalline bedrock overlaid by shallow highly permeable cambisol on
the hillslopes, whereas the thick saturated glacial deposits in the valley are overlaid by
histosols. Standard meteorological and hydrological monitoring is supplemented by
measurements of the soil moisture, soil pore water suction, water table fluctuation in
the saturated riparian zone of Äerná Nisa creek. Isotopes in water molecule 18O,
2H and 3H are analyzed in precipitation, shallow groundwater, soil pore water,
groundwater and stream outflow to select proper hypothesis about the flow formation.
Complementary sampling for the Li-isotopes (δ7Li) was performed in the period of
2008-2010 on the monthly basis in precipitation, shallow groundwater and outflow
waters.
Lithium contents fluctuate significantly between the precipitation (mean: 0.35 ± 0.21
μg/l), the shallow groundwater (mean: 1.87 ± 0.23 μg/l) and the outflow (mean: 3.10 ± 0.36
μg/l). There is no link between the Li contents and the rainfall amount but a positive trend
can be seen between Li contents and the outflow discharge. First set of Li-isotopes data shows
an increase in the δ7Li between the precipitation (mean: +5.6 ± 2.7), the shallow
groundwater (mean: +13.9 ± 4.4) and the outflow (mean: +18.4 ± 3.5). There is no
evidence of link between the δ7Li and the Li contents (as 1/Li) revealing no simple
mixing.
Comparing the data reveal causalities between content of lithium isotopes in
precipitation, shallow groundwater in wetlands and outflow from the catchment and prove
that naturally present lithium isotopes can be a very useful tool in hydrological
tracing.
This research is supported by the Czech Science Foundation projects No. 205/09/0831, by
IAEA research contract 14007, Czech Ministry of Environment No. SP/2e7/229/07 and by
BRGM Research Division. |
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