Tropospheric Phosphine and Its Sources in Coastal Antarctica

Earlier reports show very low concentrations of phosphine in remote air of the lower troposphere of nonpolar regions, in the low ng m-3 range during the night and in the pg m-3 range during daylight around noon. In this study, abnormally and unexpectedly high phosphine concentrations (30.0−407.8 ng m-3, 11 locations) were found in polar air samples collected on Millor Peninsula, eastern Antarctica and Fildes Peninsula, western Antarctica. The maximum concentration was measured in the atmosphere of penguin colonies. Field phosphine emission rates from four colonies were 8.99 ng m-2 h-1 (skua colony), 9.56 ng m-2 h-1 (gentoo penguin colony), 39.96 ng m-2 h-1 (seal colony) and 63.58 ng m-2 h-1 (empire penguin colony), respectively. Our air sampling sites are located downwind of two large penguin colonies, indicating that penguin colony emission is the predominant source for atmospheric PH3 on Millor Peninsula. Laboratory scale incubation of ornithogenic soils amended by penguin guanos yielded a maximum PH3 production rate of 0.58 ng kg-1 d-1 specifically at low temperature (4 °C). Significant concentrations of phosphine occur in the atmosphere of coastal Antarctica and confirm the existence of a small gaseous link in the phosphorus cycle of the Antarctic tundra ecosystem.