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High precision measurements of atmospheric concentrations and plant exchange rates of carbonyl sulfide using mid‐IR quantum cascade laser
Author(s) -
STIMLER KEREN,
NELSON DAVID,
YAKIR DAN
Publication year - 2010
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2009.02088.x
Subject(s) - carbonyl sulfide , water vapor , chemistry , analytical chemistry (journal) , isotopologue , mass spectrometry , atmosphere (unit) , carbon dioxide , tracer , nitrogen , carbon monoxide , environmental chemistry , sulfur , molecule , meteorology , biochemistry , nuclear physics , catalysis , physics , organic chemistry , chromatography
Linking measurements of carbonyl sulfide (COS) with those of carbon dioxide (CO 2 ) has a potential in providing a powerful tracer of gross CO 2 fluxes between the atmosphere and land plants, a critical element in understanding the response of the land biosphere to global change. A new application of online COS, CO 2 and water vapor measurements based on newly designed mid‐infrared (IR) dual quantum cascade laser (QCL) spectrometer measures COS and CO 2 (at 2056 cm −1 ) and water vapor (at 2190 cm −1 ), with detectors cooled thermoelectrically (at −43 °C) or with liquid nitrogen (−197 °C) for improved precision. Using the cryogenic detectors with averaging time of 1 s, precision was 50 pmol mol −1 , 0.4 μmol mol −1 and 0.01 mmol mol −1 for COS, CO 2 and water vapor, respectively (14, 0.2 and 0.003, respectively, for 60 s averaging time). We measured COS concentrations in ambient air, and changes in the rates of COS, CO 2 and water vapor exchange of attached leaves in response to changes in light intensity and ambient COS concentrations. The results were consistent with those of nononline gas chromatography–mass spectrometry for COS and IR gas analyzer for CO 2 and water vapor, with a high linear correlation for a broad range of concentrations ( R 2 = 0.85 for COS and R 2 = 1.00 for CO 2 and water vapor). The new methodology opens the way for lab and field explorations of COS fluxes as a powerful new tracer for CO 2 exchange in the land biosphere.