% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@INPROCEEDINGS{Gangi:172354,
      author       = {Gangi, Laura and Rothfuss, Youri and Vereecken, Harry and
                      Brüggemann, Nicolas},
      title        = {{I}dentifying and quantifying determinants of the
                      18{O}-exchangebetween {H}$_{2}${O} and {CO}$_{2}$ in soil by
                      combininglaser-based spectroscopy and gas-permeable tubing},
      reportid     = {FZJ-2014-05834},
      year         = {2013},
      abstract     = {The oxygen isotope signature of CO2 (δ18O-CO2) enables
                      partitioning the carbon gross fluxes of terrestrial
                      ecosystems related to soil respiration and plant
                      assimilation, as CO2 attains a distinct δ18O value during
                      equilibration with 18O-depleted soil water and 18O-enriched
                      leaf water, respectively. However, the interpretation of the
                      measured δ18O-CO2 from soils is still challenging because
                      the signal is influenced by different parameters, e.g. the
                      δ18O of soil water (δ18O-H2O), CO2-H2O equilibration rate
                      (depending on soil moisture, soil porosity and tortuosity as
                      well as the catalytic activity of carbonic anhydrase), and
                      soil physical properties which may vary in time and space.
                      Furthermore, the contribution of additional factors, e.g.
                      respiration by plant roots, is largely unknown. In our
                      study, we measure the 18O-exchange between soil water and
                      CO2 on-line within soil columns filled with well
                      characterized medium sand and local soil material,
                      respectively. Gas-permeable microporous polypropylene tubing
                      is installed at different depths in the soil columns and
                      purged with zero air at a low flow rate. The δ18O of CO2
                      and water vapor, which is transported from the soil into the
                      tubing, is monitored simultaneously by laser-based
                      spectroscopy. The isotopic signature of water vapor is then
                      used to infer δ18O-H2O, using well-established calibration
                      equations, and, together with the δ18O-CO2, the degree of
                      18O exchange between soil water and CO2 as well as CO2
                      diffusion through the different soil layers. We expect that
                      (i) variations in δ18O-H2O, soil water content, and soil
                      physical properties such as porosity, (ii) changes in
                      carbonic anhydrase activity, and (iii), depending on the
                      rate of CO2-H2O equilibration, respiration by plant roots
                      will be reflected in the δ18O-CO2. This new methodology
                      represents a promising tool to measure stable isotope fluxes
                      between soil and atmosphere in situ. It could provide useful
                      information for an improved parameterization of models
                      simulating the δ18O of soil CO2 fluxes, including CO2
                      invasion from the atmosphere into the soil.},
      month         = {Oct},
      date          = {2013-10-21},
      organization  = {AGU Chapman Conference: Soil-mediated
                       Drivers of Coupled Biogeochemical and
                       Hydrological Processes across Scales,
                       Tucson, Arizona (USA), 21 Oct 2013 - 24
                       Oct 2013},
      cin          = {IBG-3},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {246 - Modelling and Monitoring Terrestrial Systems: Methods
                      and Technologies (POF2-246) / 255 - Terrestrial Systems:
                      From Observation to Prediction (POF3-255)},
      pid          = {G:(DE-HGF)POF2-246 / G:(DE-HGF)POF3-255},
      typ          = {PUB:(DE-HGF)1},
      url          = {https://juser.fz-juelich.de/record/172354},
}