HR: 08:50h
AN: B21E-04    [Abstracts]
TI: Can Carbonyl Sulfide Help Constrain Gross Vegetative Fluxes of Carbon Dioxide?
AU: * Montzka, S
EM: stephen.a.montzka@noaa.gov
AF: NOAA, 325 Broadway, Boulder, CO 80305 United States
AU: Tans, P
EM: Pieter.Tans@noaa.gov
AF: NOAA, 325 Broadway, Boulder, CO 80305 United States
AB: Uptake by vegetation represents an important loss mechanism for atmospheric carbonyl sulfide (COS). COS undergoes rapid reaction by carbonic anhydrase and Rubisco, the same enzymes involved in the initial stages of carbon assimilation by vegetation. Measurements of COS during multiple years show large seasonal variations in the northern hemispheric atmosphere that are strongly related to those observed for CO$_{2}$; the seasonal changes observed for COS, however, are about eight times larger on a relative basis. Our current understanding of sources and sinks of COS and CO$_{2}$ suggests that this amplified seasonality arises for COS because its uptake flux is not diminished, as is the case for CO$_{2}$, by emissive fluxes associated with respiration and retro-diffusion of unassimilated CO$_{2}$ from leaf stomata. These results imply that the large-scale variations observed for COS in the northern hemispheric atmosphere reflect primarily the magnitude of gross vegetative uptake fluxes. They further suggest the possibility that COS could provide unique constraints on gross vegetative uptake fluxes of CO$_{2}$.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions
DE: 0365 Troposphere--composition and chemistry
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting