Measurements of Carbonyl sulfide (OCS) fluxes were carried out on bog microcosms using chamber sampling and tunable diode laser analysis. Intact bog microcosms (vascular plants, mosses, and peat) removed ambient levels of OCS in the light and dark with rates from -2.4 to -8.1 ng S min-1 m-2. Peat and peat plus mosses emitted OCS in the light with rates of 17.4 and 10.9 ng S min-1 m-2, respectively. In the dark, the mosses apparently removed OCS at a rate equivalent to the peat emissions. A 3-D numerical tracer model using this data indicated that boreal bog ecosystems remove at most 1% of ambient OCS, not sufficient to account for an observed OCS depletion in boreal air masses. ¿ American Geophysical Union 1993