Phosphine in the marine atmosphere along a hemispheric course from China to Antarctica

The gas phosphine (PH₃) is a part of an atmospheric link of the phosphorus cycle on earth. Previous research reported the terrestrial lower tropospheric PH₃ at night in the 1 ng m^?3 range in remote areas, with the peak of 100 ng m^?3 in populated areas, and at daytime even lower concentrations in the pg m^?3 range. The data of the global marine atmospheric PH₃ are still very sparse.This study presents surprisingly high concentrations of PH₃ in the order of 0.1–1 μg m^?3 in many of 32 samples of the marine atmosphere in the latitudinal range from 30°N to 65°S (the cruise of research ship Xuelong from Shanghai Harbor, China, to Antarctica). The highest concentrations were measured near coastal areas of Eastern Asia and Western Australia. A significant correlation exists between marine atmospheric PH₃ concentration and air temperature at 22:00 (local time). PH₃ concentrations at different latitudes strongly decline with daylight intensity according to a logarithmic relationship. These surprisingly high concentrations of the readily oxidizable PH₃ in the air indicate hitherto unknown but important PH₃ emission sources in marine environment. More work is necessary to evaluate the sources of atmospheric PH₃ from marine biosphere.