Dissertation / PhD Thesis/Book

FZJ-2015-04845

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Real-time quantification of oxygen isotope exchange between carbon dioxide and leaf /soil water in terrestrial ecosystems with laser-based spectroscopy

Gangi, L. (Corresponding author)FZJ*

2015
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-061-6

Please use a persistent id in citations: http://hdl.handle.net/2128/9009  urn:nbn:de:0001-2015071629

Abstract: The oxygen isotope ratio of atmospheric carbon dioxide ($\delta^{18}$O-CO$_{2}$) can be used to partition thegross fluxes of CO$_{2}$ in terrestrial ecosystems, such as soil respiration and plant assimilation, asa characteristic $\delta^{18}$O value is transferred to CO$_{2}$ during isotopic equilibration with differentwater pools. However, the quantitative use of $\delta^{18}$O-CO$_{2}$ requires a detailed understanding of the different processes and factors that influence the CO$_{2}$–H$_{2}$O oxygen isotope exchange atdifferent scales. The effect of varying environmental conditions on the $^{18}$O-exchange between atmospheric CO$_{2}$ and the leaf water of different plant species has been insufficiently explored in experiments, and also the $\delta^{18}$O of soil efflux is fraught with uncertainty due to the complex influence of soil water content (SWC), soil texture and tortuosity, as well as the catalytic activity of the enzyme carbonic anhydrase (CA). The aim of the present study was to elucidate the $^{18}$O-exchange between CO$_{2}$ and leaf/soil water under controlled laboratory conditions and at a hightemporal resolution. For this purpose, $\delta^{18}$O of CO$_{2}$ and water vapor were measured online using infrared laser spectroscopy in plant chamber experiments with spruce, wheat, poplar and maize, as well as soil column experiments, which included the use of gas-permeable tubing. Finally, the biophysical soil–vegetation–atmosphere model MuSICA was applied to simulate the $^{18}$O-exchange at the ecosystem level and to test whether a value for the degree of isotopic equilibrium ($\theta$) obtained from plant chamber experiments was suitable for model parameterization. [...]

Note: Universität Bonn, Diss., 2015

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 255 - Terrestrial Systems: From Observation to Prediction (POF3-255) (POF3-255)

Appears in the scientific report 2015

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Database coverage:

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