Marine nitrogen fixation as a possible source of atmospheric water-soluble organic nitrogen aerosols in the subtropical North Pacific

Water-soluble organic nitrogen (WSON) in marine aerosols can affect the atmospheric photochemical field and biogeochemical cycling of bioelements. Cruise observation along 23ºN over the subtropical North Pacific showed that the fine-mode WSON concentration in the eastern North Pacific (200–240ºE) was significantly higher than that in the western North Pacific (135–200ºE). The authors suggested that dissolved organic nitrogen (DON) and ammonium, produced and exuded by N₂-fixing microorganisms in surface seawater (SSW), contributed to the formation of WSON aerosols, based on the stable carbon isotope analysis and positive relations among N₂-fixation rate, DON in SSW, and the WSON concentrations. The study provides new insights into the role of ocean-derived reactive nitrogen in the atmosphere associated with marine N₂-fixing microorganisms.

Reference: Dobashi, T., Miyazaki, Y., Tachibana, E., et al., (2023). Marine nitrogen fixation as a possible source of atmospheric water-soluble organic nitrogen aerosols in the subtropical North Pacific. Biogeosciences, 20(2), 439–449. https://doi.org/10.5194/bg-20-439-2023