Abstract
Recent studies have suggested that carbonyl sulfide (COS) can be used as a proxy for partitioning between photosynthetic uptake and respiratory emission of CO2, a balance which cannot be directly determined through the measurement of CO2 fluxes. COS is the most abundant sulfur containing gas in the atmosphere, with a dominant sink in the terrestrial biosphere. COS is taken up by plants through photosynthesis, but is not respired. It is also lost via uptake to soils. However, in terrestrial ecosystems the magnitudes of soil vs. leaf uptake are not well resolved. We report data from direct, continuous measurements of COS using infrared laser absorption (3 std deviation of less than 10 ppt in 30 s), operated continuously since October, 2010 at Harvard Forest in Western Massachusetts. These data were collected in parallel with long term CO2 and H2 flux measurements. We present seasonal variations of the gradients and fluxes of COS through the forest canopy. Additionally, we investigate the relationship of COS with photosynthesis and soil processes through comparison with CO2 and H2 trace gases, respectively。下不下来

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