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| Titel |
Reconnection of Danube Floodplains: Use of stable isotopes to determine the effects on nitrogen cycling |
| VerfasserIn |
Nina Welti, Elisabeth Bondar-Kunze, Matthias Mair, Wolfgang Wanek, Patricia Bonin, Gilles Pinay, Thomas Hein |
| 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 |
250052538
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| Zusammenfassung |
| The Danube River and its waters have been changed to fit the needs of society for agriculture
and hydro-power. Particularly, there is a significant decrease of hydrologic exchange
of surface waters. The secondary channels and various water bodies within the
floodplain are disconnected from the main river flow for long periods. In order to
counteract these negative impacts on the floodplains, large scale restoration projects
aim to increase hydrologic exchange with the floodplain. Yet, the consequences of
reconnection on nitrogen cycling are less clear. In this study, floodplain reconnection and
disconnection have been mimicked in mesocosm experiments to understand the effect
on nitrate uptake and particularly, denitrification. The presented study quantified
the rates of denitrification using short term mesocosm incubations with 15N-NO3
tracing to follow the pathway of nitrate uptake within different floodplain sections.
Triplicate sediment samples from two sites were incubated in the laboratory for five
days in 25L mesocosms. The nitrate delivery regime and dissolved carbon content
where changed to mimic disconnection and reconnection schemes. Denitrification,
anammox, and DNRA rates were calculated based on isotopic analysis using a
comprehensive mathematical calculation. Water sediment interactions changed
which changed the rate of denitrification as well as the relationship between N2 and
N2O. We present how floodplain disconnection promotes N2O production, while
floodplain reconnection promotes complete denitrification, resulting in N2 production. |
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