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.