Free amino acids in marine aerosols over the western North Pacific Ocean

Atmospheric input of fixed nitrogen species to the ocean has attracted considerable attention from the viewpoint of the oceanic biogeochemical cycle of nitrogen, although few measurements of organic nitrogen compounds in atmospheric aerosols have been extensively conducted over remote ocean areas. In this study, we report the geographical distribution of dissolved free amino acids (DFAA) in the water-soluble fraction of two size-segregated marine aerosols over the western North Pacific. The concentrations of DFAA showed higher values over the region north of 30°N, whereas they clearly decreased south of 30°N. Approximately 59–96% of DFAA was found in fine-mode particles. Long-range transport from continental sources could largely contribute to DFAA in marine aerosols over the remote North Pacific.