A one-dimensional photochemical model is used to simulate the sulfur cycle in the marine atmosphere. Reduced organic sulfur compounds, including carbon disulfide (CS2), hydrogen sulfide (H2S), carbonyl sulfide (OCS), and dimethyl sulfide (DMS), are released from the ocean surface to the atmosphere, where they are oxidized to SO2 and particulate sulfate. CS2 concentrations reported over the oceans are an order of magnitude higher than those expected on the basis of a 0.5 Tg S yr-1 source estimated from water column measurements; the discrepancy may reflect continental contamination. We require a sink for OCS of magnitude 1--4 Tg S yr-1 in order to balance its budget; known photochemical processes are inadequate, but uptake by land plants could be important. H2S concentrations are consistent with an oceanic source of 1--5 Tg S yr-1. Most of the SO2 in the marine atmosphere apparently derives from oxidation of DMS, which has an estimated source of about 40 Tg S yr-1. The main loss process for DMS is reaction with OH, but reaction with NO3 may also be important. SO2 concentrations increase with altitude in the marine troposphere, while sulfate concentrations decrease with altitude; this behavior may result from rapid heterogeneous removal of SO2 in the boundary layer or from altitude variations in the branching ratio for DMS oxidation rather than from the ''tropical cloud pumping'' mechanism, which has been proposed previously as the explanation. Measurements that could improve our understanding of the marine sulfur cycle are suggested. ¿ American Geophysical Union 1987