Carbonyl sulfide (COS) as a tracer for canopy photosynthesis, transpiration and stomatal conductance : potential and limitations

  • The theoretical basis for the link between the leaf exchange of carbonyl sulfide (COS), carbon dioxide (CO2) and water vapour (H2O) and the assumptions that need to be made in order to use COS as a tracer for canopy net photosynthesis, transpiration and stomatal conductance, are reviewed. The ratios of COS to CO2 and H2O deposition velocities used to this end are shown to vary with the ratio of the internal to ambient CO2 and H2O mole fractions and the relative limitations by boundary layer, stomatal and internal conductance for COS. It is suggested that these deposition velocity ratios exhibit considerable variability, a finding that challenges current parameterizations, which treat these as vegetation-specific constants. COS is shown to represent a better tracer for CO2 than H2O. Using COS as a tracer for stomatal conductance is hampered by our present poor understanding of the leaf internal conductance to COS. Estimating canopy level CO2 and H2O fluxes requires disentangling leaf COS exchange from other ecosystem sources/sinks of COS. We conclude that future priorities for COS research should be to improve the quantitative understanding of the variability in the ratios of COS to CO2 and H2O deposition velocities and the controlling factors, and to develop operational methods for disentangling ecosystem COS exchange into contributions by leaves and other sources/sinks. To this end, integrated studies, which concurrently quantify the ecosystem-scale CO2, H2O and COS exchange and the corresponding component fluxes, are urgently needed. We investigate the potential of carbonyl sulfide (COS) for being used as a tracer for canopy net photosynthesis, transpiration and stomatal conductance by examining the theoretical basis of the link between leaf COS, carbon dioxide (CO2) and water vapour (H2O) exchange. Our analysis identifies several limitations that need to be overcome to this end, however at present we lack appropriate ecosystem-scale field measurements for assessing their practical significance. It however appears that COS represents a better tracer for CO2 than H2O. Concurrent measurements of ecosystem scale COS, CO2 and H2O exchange are advocated.

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Metadaten
Author:Georg Wohlfahrt, Federico Brilli, Lukas Hörtnagl, Xiaobin Xu, Heinz BingemerGND, Armin HanselORCiD, Francesco Loreto
URN:urn:nbn:de:hebis:30:3-257879
DOI:https://doi.org/10.1111/j.1365-3040.2011.02451.x
ISSN:1365-3040
ISSN:0140-7791
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/22017586
Parent Title (English):Plant, cell & environment
Publisher:Wiley-Blackwell
Place of publication:Oxford [u.a.]
Document Type:Article
Language:English
Year of Completion:2012
Year of first Publication:2012
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2012/08/16
Tag:carbon dioxide; gross photosynthesis; internal conductance; net photosynthesis; water vapour
Volume:35
Page Number:11
First Page:657
Last Page:667
Note:
Copyright © 2011 Blackwell Publishing Ltd. Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
HeBIS-PPN:357947495
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung-Nicht kommerziell 3.0