Abstract
Atmospheric measurements of radon and hydrogen sulfide, and seawater measurements of total sulfide, free sulfide, and carbonyl sulfide, were made on a cruise in the western North Atlantic Ocean (October 24 to November 9, 1989). Measured values for (super 222) Rn ranged from 3 to 70 pCi m (super -3) , those for atmospheric hydrogen sulfide from 1 to 85 parts per trillion, and those for dissolved total and free sulfide in seawater from 33 to 930 pmol L (super -1) and 0 to 73 pmol L (super -1) , respectively. A positive correlation between (super 222) Rn and atmospheric H (sub 2) S was observed. Both (super 222) Rn and H (sub 2) S were high in air masses traced back to North America. Measurements in seawater showed that uncomplexed sulfides were approximately 13% of total sulfide at 2 m depth. Atmospheric H (sub 2) S and dissolved H (sub 2) S in seawater were usually not far from saturation equilibrium. Our results indicate that the ocean acted at some times as a source of atmospheric H (sub 2) S but more frequently as a sink. Hydrolysis of COS and atmospheric deposition of H (sub 2) S both may contribute to the budget of dissolved sulfide in seawater of the western North Atlantic Ocean. On a global scale the ocean/atmosphere exchange of H (sub 2) S appears to play a minor role in the atmospheric sulfur cycle. Copyright 1991 by the American Geophysical Union.