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| Titel |
A new method combining soil oxygen concentration measurements with the quantification of gross nitrogen turnover rates and associated formation of N2O and N2 emissions |
| VerfasserIn |
Adrian Gütlein, Michael Dannenmann, Christoph Sörgel, Rudi Meier, Astrid Meyer, Ralf Kiese |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096543
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| Publikation (Nr.) |
 EGU/EGU2014-12051.pdf |
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| Zusammenfassung |
| Climate change and the expansion of land use have led to significant changes in terrestrial
ecosystems. These include changes in the biogeochemical cycle of nitrogen and therewith
implications for biodiversity, water cycle and pedosphere-atmosphere exchange. To
understand these impacts detailed research on nitrogen turnover and fluxes are
conducted at various (semi-) natural and managed ecosystems in the Mt. Kilimanjaro
region. In this context, we execute 15N tracing analyses on soil samples in our stable
isotope laboratory including a new experimental setup. The soils were sampled from
different forest ecosystems of Mt. Kilimanjaro varying in altitude (1600 – 4500 m) and
will be analyzed for gross rates of ammonification and nitrification, gross rates
of microbial inorganic N uptake as well as for the gaseous losses of ^15N2 and
^15N2O using ^15NH4+ and ^15NO3- tracing and pool dilution approaches. Since
nitrogen turnover of nitrification and denitrification is dependent on soil oxygen
concentrations we developed an incubation method which allows to adjust soil samples to
different oxygen concentrations. For this purpose, soil is incubated in glass bottles with
side tubes to ensure a constant gas flow over the whole incubation time. To adjust
the oxygen levels in the laboratory experiment as close as possible to the natural
conditions, we started to monitor soil oxygen concentrations with a FirestingO2 Sensor
(Pyroscience) connected to a timer and a datalogger (MSR 145 IP 60 E3333) at a Mt.
Kilimanjaro rainforest site. The equipment is complemented with soil temperature,
moisture and pressure sensors (MSR 145 IP 60). A solar panel connected to an energy
source guarantees a working time for over 2 years by a measuring frequency of 20
seconds each 30 minutes. The new laboratory incubation method together with in-situ
oxygen concentration measurements in soils will facilitate laboratory incubations
with realistic oxygen concentrations and thus will allow for a better understanding
of temporal variability of nitrogen turnover rates and associated gaseous losses. |
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