Air-to-sea deposition of water-soluble total nitrogen (WSTN) can influence the primary productivity in the coastal oceans. Here, we assessed the concentrations of aerosol inorganic (WSIN: NH₄⁺ + NO₃⁻) and WSTN over the Arabian Sea during winter season (SS379:6–24 December 2018). The mean concentrations of NH₄⁺ (109 ± 83 nmol m⁻³) overwhelm that of NO₃⁻ (32 ± 13 nmol m⁻³) and water-soluble organic nitrogen (WSON: WSTN-WSIN: 86 ± 81 nmol m⁻³), and contributing to ~50 ± 31% of WSTN mass. Significant linear relationships of WSON with water-soluble organic carbon and NH₄⁺ with non-sea-salt (nss)-K⁺ is observed suggesting their common origin from biomass burning and fertilizers. Backward air mass trajectories and satellite-based fire counts further revealed their provenance in the Indo-Gangetic Plain and southern India. The concentration of NO₃⁻ moderately correlated with nssCa²⁺ (dust tracer), indicating heterogeneous reactive uptake on mineral aerosol surface. Despite high concentrations, the deposition fluxes of NH₄⁺ (~9.4 ± 7.1 μmol m⁻² d⁻¹) and WSON (7.4 ± 7.0 μmol m⁻² d⁻¹) are lower than NO₃⁻ (27 ± 11 μmol m⁻² d⁻¹) because of their predominant fine nature (i.e., strong correlation with nss-SO₄²⁻). We also constrained the total annual atmospheric deposition rates of WSIN (0.94 Tg yr⁻¹) and WSON (0.08 Tg yr⁻¹) to the Arabian Sea during the continental outflow (November-April). The maximum dry-deposition of WSON to the Arabian Sea (0.24 Tg yr⁻¹) is twice that of the riverine supply (0.11 Tg yr⁻¹), highlighting the significance of aeolian sources. By using Redfield Stoichiometry, the WSTN deposition (21–73 μmol m⁻² d⁻¹) can account for <5.3% of fixed‑carbon by a primary production in the Arabian Sea.

水溶性总氮（WSTN）的海空沉积会影响沿海海洋的初级生产力。：在这里，我们评估气溶胶无机的浓度（NH WSIN ₄ ⁺ + NO ₃ ^-在冬季阿拉伯海和WSTN（SS379：12月6日至24日2018））。NH的平均浓度₄ ⁺（109±83纳摩尔米^-3）压倒该NO的₃ ^-（32±13纳摩尔米^-3）和水溶性有机氮（WSON：WSTN-WSIN：86±81纳摩尔米^{- 3} ），并贡献了WSTN质量的〜50±31％。WSON与水溶性有机碳和NH ₄ ^+的显着线性关系含有非海盐（nss）-K ^+的化合物表明它们的共同来源是生物质燃烧和肥料。向后的空气质量轨迹和基于卫星的火计数进一步揭示了它们在印度恒河平原和印度南部的起源。NO的浓度₃ ^-与NSS中度相关的Ca ²⁺（灰尘示踪剂），这表明在矿物气溶胶表面异质反应性摄取。尽管高浓度，NH的沉积通量₄ ⁺（〜9.4±7.1微摩尔米^-2 d ^-1）和WSON（7.4±7.0微摩尔米^-2 d ^-1）比低NO ₃ ^-（27±11微摩尔米^-2 d ^-1），因为它们具有优良的优良性质（即与nss-SO ₄ ^2-的相关性强）。我们还限制了大陆外流（11月至4月）期间WSIN（0.94 Tg yr ^-1）和WSON（0.08 Tg yr ^-1）在阿拉伯海的总年度大气沉积速率。WSON在阿拉伯海的最大干沉降量（0.24 Tg yr ^-1）是河流供应量的最大干沉降量（0.11 Tg yr ^-1 ）的两倍，突显了风源的重要性。通过使用Redfield化学计量，WSTN沉积（21–73μmolm ^-2 d ^-1）占阿拉伯海一次生产的固定碳量的<5.3％。