Real-time quantification of oxygen isotope exchange between carbon dioxide and leaf /soil water in terrestrial ecosystems with laser-based spectroscopy
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The oxygen isotope ratio of atmospheric carbon dioxide (δ18O-CO2) can be used to partition the gross fluxes of CO2 in terrestrial ecosystems, such as soil respiration and plant assimilation, as a characteristic δ18O value is transferred to CO2 during isotopic equilibration with different water pools. However, the quantitative use of δ18O-CO2 requires a detailed understanding of the different processes and factors that influence the CO2–H2O oxygen isotope exchange at different scales. The effect of varying environmental conditions on the 18O-exchange between atmospheric CO2 and the leaf water of different plant species has been insufficiently explored in experiments, and also the δ18O 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 18Oexchange between CO2 and leaf/soil water under controlled laboratory conditions and at a high temporal resolution. For this purpose, δ18O of CO2 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 18Oexchange at the ecosystem level and to test whether a value for the degree of isotopic equilibrium (θ) obtained from plant chamber experiments was suitable for model parameterization.
Buchkauf
Real-time quantification of oxygen isotope exchange between carbon dioxide and leaf /soil water in terrestrial ecosystems with laser-based spectroscopy, Laura Gangi
- Sprache
- Erscheinungsdatum
- 2015
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- Titel
- Real-time quantification of oxygen isotope exchange between carbon dioxide and leaf /soil water in terrestrial ecosystems with laser-based spectroscopy
- Sprache
- Englisch
- Autor*innen
- Laura Gangi
- Erscheinungsdatum
- 2015
- ISBN10
- 3958060617
- ISBN13
- 9783958060616
- Kategorie
- Skripten & Universitätslehrbücher
- Beschreibung
- The oxygen isotope ratio of atmospheric carbon dioxide (δ18O-CO2) can be used to partition the gross fluxes of CO2 in terrestrial ecosystems, such as soil respiration and plant assimilation, as a characteristic δ18O value is transferred to CO2 during isotopic equilibration with different water pools. However, the quantitative use of δ18O-CO2 requires a detailed understanding of the different processes and factors that influence the CO2–H2O oxygen isotope exchange at different scales. The effect of varying environmental conditions on the 18O-exchange between atmospheric CO2 and the leaf water of different plant species has been insufficiently explored in experiments, and also the δ18O 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 18Oexchange between CO2 and leaf/soil water under controlled laboratory conditions and at a high temporal resolution. For this purpose, δ18O of CO2 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 18Oexchange at the ecosystem level and to test whether a value for the degree of isotopic equilibrium (θ) obtained from plant chamber experiments was suitable for model parameterization.