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| Titel |
Influence of Dynamic Hydraulic Conditions on Nitrogen Cycling in Column Experiments |
| VerfasserIn |
Niklas Gassen, Frederick von Netzer, Evgenia Ryabenko, Tillmann Lüders, Christine Stumpp |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111659
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| Publikation (Nr.) |
 EGU/EGU2015-11799.pdf |
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| Zusammenfassung |
| In order to improve management strategies of agricultural nitrogen input, it is of major
importance to further understand which factors influence turnover processes within the
nitrogen cycle. Many studies have focused on the fate of nitrate in hydrological systems, but
up to date only little is known about the influence of dynamic hydraulic conditions on the fate
of nitrate at the soil-groundwater interface. We conducted column experiments with natural
sediment and compared a system with a fluctuating water table to systems with
different water content and static conditions under the constant input of ammonia into
the system. We used hydrochemical methods in order to trace nitrogen species,
15N isotope methods to get information about dominating turnover processes and
microbial community analysis in order to connect hydrochemical and microbial
information.
We found that added ammonia was removed more effectively under dynamic hydraulic
conditions than under static conditions. Furthermore, denitrification is the dominant
process under saturated, static conditions, while nitrification is more important
under unsaturated, static conditions. We conclude that a fluctuating water table
creates hot spots where both nitrification and denitrification processes can occur
spatially close to each other and therefore remove nitrogen more effectively from the
system. Furthermore, the fluctuating water table enhances the exchange of solutes and
triggers hot moments of solute turnover. Therefore we conclude that a fluctuating
water table can amplify hot spots and trigger hot moments of nitrogen cycling. |
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