Free (FAAs) and combined amino acids (CAAs) were investigated on size-resolved samples of nascent sea spray aerosol (SSA) particles generated during controlled laboratory experiments. Compared to seawater, the amino acids were strongly enriched on the SSA particles. The enrichment factors (EF_aer) on submicron SSA particles (EF_aer∑FAA: 2.5 × 10⁶ and EF_aer∑CAA: 7.9 × 10⁵) were 1–2 orders of magnitude higher than on supermicron ones (EF_aer∑FAA: 1.0 × 10⁵ and EF_aer∑CAA: 7.3 × 10⁴) and continuously increased toward smaller SSA particles. Molecular-level analysis showed that the more polar the FAAs, the more they are enriched on the SSA particles (especially FAAs with polar acid side chains, e.g., aspartic acid: EF_aer of 5.8 × 10⁶). Comparison of the amino acids present on nascent SSA with those present on ambient marine aerosol particles revealed a higher complexity of the amino acids of the nascent SSA, suggesting that atmospheric processes likely reduce the amino acid diversity. In addition, our results highlight that although almost all the amino acids studied are transferred to the atmosphere via bubble bursting under controlled conditions, two amino acids, γ-aminobutyric acid (GABA) and glycine likely have additional sources to the atmosphere. GABA is likely formed on ambient marine submicron aerosol particles to a large extent (35–47% of ∑FAA). Glycine likely originates from long-range transport processes or photochemical reactions, as discussed in the literature; however, our results highlight the potential for a direct oceanic source via bubble bursting (∼20% of ∑FAA). Overall, bubble-bursting-derived total amino acids made up 11–18% of the mass of dissolved organic carbon on the submicron SSA particles.

中文翻译：

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海喷雾气溶胶室研究游离氨基酸和结合氨基酸的选择性转移和富集

对在受控实验室实验中产生的新生海喷雾气溶胶 (SSA) 颗粒的大小分辨样品进行了游离 (FAA) 和组合氨基酸 (CAA) 的研究。与海水相比，氨基酸在 SSA 颗粒上高度富集。亚微米 SSA 颗粒（EF _aer∑FAA：2.5 × 10 ⁶和 EF _aer∑CAA：7.9 × 10 ⁵）的富集因子（EF _aer）比_超微米颗粒（EF _aer∑FAA： 1.0 × 10 ⁵和 EF _aer∑CAA : 7.3 × 10 ⁴) 并朝着更小的 SSA 颗粒不断增加。分子水平分析表明，FAA 的极性越强，它们在 SSA 颗粒上的富集就越多（尤其是具有极性酸性侧链的 FAA，例如天冬氨酸：EF _aer为 5.8 × 10 ⁶）。将新生 SSA 上存在的氨基酸与周围海洋气溶胶颗粒上存在的氨基酸进行比较，显示新生 SSA 中氨基酸的复杂性更高，这表明大气过程可能会降低氨基酸的多样性。此外，我们的结果强调，虽然几乎所有研究的氨基酸都在受控条件下通过气泡破裂转移到大气中，但两种氨基酸，γ-氨基丁酸 (GABA) 和甘氨酸可能有额外的大气来源。GABA 可能在很大程度上形成于环境海洋亚微米气溶胶颗粒上（∑FAA 的 35-47%）。正如文献中所讨论的，甘氨酸可能源自长距离传输过程或光化学反应；然而，我们的结果突出了通过气泡破裂（∑FAA 的 20%）直接产生海洋源的潜力。总体而言，气泡破裂衍生的总氨基酸占亚微米 SSA 颗粒上溶解有机碳质量的 11-18%。