The Production of Methylated Sulfur Compounds by Marine Phytoplankton

Intensive study of the global cycle of sulfur in recent years has revealed the requirement for substantial natural inputs of sulfur into the atmosphere to balance the measured rates of deposition (Friend, 1973). Estimates of the oceanic contribution of reduced sulfur to the atmosphere, usually derived by difference rather than actual measurement, vary from 30 to 202 Tg yr−1. The role of H₂S in this process has been debated (Slatt et a1., 1978), and methylated sulfur compounds have been commonly suggested as transfer agents (Rasmussen, 1974; Nguyen et al., 1978). The evaluation of the true magnitude of these fluxes is not yet possible due to the scarcity of measurements of the concentrations of the volatile sulfur compounds in seawater and the marine atmosphere.