Seawater and Atmospheric Methylamines, Ammonia/Ammonium, Sea–Air Fluxes, and Onboard Microcosm Incubation Data From the Northwest Pacific

This dataset supports research on methylamine and ammonia/ammonium concentrations and sea–air exchange in the Northwest Pacific. It includes seawater observations of trimethylaminium (TMAH⁺), dimethylaminium (DMAH⁺), and ammonium (NH₄⁺); atmospheric observations of trimethylamine (TMA), dimethylamine (DMA), and ammonia (NH₃); sea–air flux data; onboard natural-seawater microcosm incubation data; and a compilation of previously published marine methylamine observations. Field observations were obtained during Northwest Pacific research cruises in 2021, 2023, and 2024. The accompanying README and data dictionary provide information on variables, units, detection-limit treatment, flux sign conventions, and dataset structure.