Dimethyl sulfide and its oxidation products in the atmosphere of the Atlantic and Southern Oceans, Atmos

Abstract--Dimethyl su fide, methane sulfonate, non-sea-salt sulfate and sulfur dioxide concentrations i air were obtained uring a cruise between the U.K. and the Antarctic during the period October 1992-January 1993. In equatorial regions (30°N to 30°S) the atmospheric DMS concentration ranged from 3 to 46 ng (S)m-3 with an average of 18 ng(S)m-3. In the polar waters and regions outh of the Falkland Islands concentrations from 3 to 714 ng(S)m-3 were observed with a mean concentration of 73 ng(S)m-3. Methane sullbnate concentrations were also enhanced inthe vicinity of the Antarctic Peninsula nd in the Weddell Sea. A simple model of DMS oxidation was used to estimate the ocean to atmosphere flux rate, and this was found to be within the range of previous estimates, with a mean value of 1011 ng (S) m- z h- 1. Key word in,tex: Dimethyl sulfide, Antarctica, erosol.]iNTRODUCTION Dimethyl sulfide is one of the breakdown products of dimethyl sulfoniopropionate (DMSP), a compound involved in regulating cellular osmotic pressure in marine algae (Dickson et al., 1980). Once released into sea water, the gas transfers across the water-air inter-face, as a result of its appreciable concentration gradi