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Abstract. Asian dust has been reported to carry anthropogenic reactive nitrogen during transport from source areas to the oceans. In this study, we attempted to characterize NH 4 and NO − 3 in each total suspended particle (TSP) sample, the samples can be classified into increasing or decreasing types. In Category 1, the concentrations of NH + 4 and NO − 3 were 20-440 % higher in dust day samples relative to samples collected immediately before or after a dust event. These concentrations decreased by 10-75 % in the dust day samples in Categories 2 and 3. Back trajectory analysis suggested that multiple factors, such as the transport distance prior to the reception site, the mixing layer depth on the transport route and the residence time across highly polluted regions, might affect the concentrations of NH .

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A series of selective dissolution experiments were conducted on the hydrogenic ferromanganese crusts collected near Line Island to study the geochemistry of Mn, Fe, Cu, Co, Ni and Ti. Despite of the fact that the very close intergrowth between amorphous ferric oxyhydroxides and δ-MnO 2 exists in the hydrogenic ferromanganese crusts, there is no isomorphous substitution between iron and manganese. This is because the two elements in oxides have different crystal chemistry and geochemistry, such assertion being in agreement with the results of selective dissolution experiments. Transitional metal elements such as Cu, Co, Ni and Ti are enriched in different phases, i.e. Ni and Co are incorporated into δ-MnO 2 while Cu and Ti are incorporated into ferric oxyhydroxides. The distributions of the elements in amorphous ferric oxyhydroxides and δ-MnO 2 are controlled by the existing states of the elements in the seawater and the crystal chemistry and geochemistry of these elements/ions in oxides.