Sulfur isotopic composition of surface snow along a latitudinal transect in East Antarctica

The sulfur stable isotopic values (δ34S) of sulfate aerosols can be used to assess oxidation pathways and contributions from various sources, such as marine biogenic sulfur, volcanoes, and sea salt. However, because of a lack of observations, the spatial distribution of δ34S values in Antarctic sulfate aerosols remains unclear. Here we present the first sulfur isotopic values from surface snow samples along a latitudinal transect in eastern Dronning Maud Land, East Antarctica. The δ34S values of sulfate showed remarkably uniform values, in the range of 14.8–16.9‰, and no significant decrease toward the inland part of the transect was noted. These results suggest that net isotopic fractionation during long-range transport is insignificant. Thus, the δ34S values can be used to infer source contributions. The δ34S values suggest that marine biogenic sulfur is the dominant source of sulfate aerosols, with a fractional contribution of 84 ± 16%.