Abstract. Transparent exopolymer particles (TEP) exhibit the properties of gels and are ubiquitously found in the world oceans. Possibly, TEP may enter the atmosphere as part of sea spray aerosol. Here, we report number concentrations of TEP (diameter > 4.5 µm) in ambient aerosol and cloud water samples from the tropical Atlantic Ocean as well as in generated aerosol particles using a plunging waterfall tank that was filled with the ambient sea water. The ambient TEP concentrations ranged between 7 × 10² and 3 × 10⁴ #TEP m⁻³ in supermicron aerosol particles and correlations to sodium (Na⁺) and calcium (Ca²⁺) (R² = 0.5) suggested some contribution via bubble bursting. Cloud water TEP concentrations were between 4 × 10⁶ and 9 × 10⁶ #TEP L⁻¹ corresponding to equivalent air concentrations of 2–4 × 10³ #TEP m⁻³. The TEP concentrations in the tank-generated aerosol particles, produced from the same waters and sampled with an equivalent system, were significantly lower (4 × 10²–2 × 10³ #TEP m⁻³) compared to the ambient concentrations. Based on Na⁺ concentrations in seawater and in the atmosphere, the enrichment factor for TEP in the atmosphere was calculated. The tank-generated TEP were enriched by a factor of 50 compared to sea water and, therefore, in-line with published enrichment factors for supermicron organic matter in general and TEP specifically. TEP enrichment in the ambient atmosphere was on average 1 × 10³ in cloud water and 9 × 10³ in ambient aerosol particles and therefore about two orders of magnitude higher than the corresponding enrichment from the tank study. Such high enrichment of supermicron particulate organic constituents in the atmosphere is uncommon and we propose that atmospheric TEP concentrations resulted from a combination of enrichment during bubble bursting transfer from the ocean and TEP in-situ formation in atmospheric phases. Abiotic in-situ formation might have occurred from aqueous reactions of dissolved organic precursors that were present in particle and cloud water samples, while biotic formation involves bacteria, which were abundant in the cloud water samples. The ambient TEP number concentrations were two orders of magnitude higher than recently reported ice nucleating particle (INP) concentrations measured at the same location. As TEP likely possess good properties to act as INP, in future experiments it is worth studying if a certain part of TEP contributes a fraction of the biogenic INP population.

中文翻译：

---

环境气溶胶颗粒和云水中高浓度的透明外聚体颗粒 (TEP)——热带大西洋的案例研究

摘要。透明外聚合物颗粒 (TEP) 具有凝胶的特性，在世界海洋中无处不在。可能，TEP 可能作为海浪气溶胶的一部分进入大气。在这里，我们报告了来自热带大西洋的环境气溶胶和云水样本中 TEP（直径 > 4.5 µm）的数量浓度，以及使用充满环境海水的跌落瀑布水箱生成的气溶胶颗粒中的浓度。超微米气溶胶颗粒中的环境 TEP 浓度介于 7 × 10 ²和 3 × 10 ⁴ #TEP m ^{-3 之间}，并且与钠 (Na ⁺ ) 和钙 (Ca ²⁺ ) (R ²= 0.5) 建议通过泡沫破裂做出一些贡献。云水 TEP 浓度介于 4 × 10 ⁶和 9 × 10 ⁶ #TEP L ^{-1 之间，}对应于 2–4 × 10 ³ #TEP m ^{-3 的}等效空气浓度。与环境浓度相比，由相同水域产生并使用等效系统采样的罐产生的气溶胶颗粒中的 TEP 浓度显着降低（4 × 10 ² –2 × 10 ³ #TEP m ^-3）。基于 Na ⁺海水和大气中的浓度，计算了大气中 TEP 的富集因子。与海水相比，水箱产生的 TEP 浓缩了 50 倍，因此，与公布的超微米有机物一般和 TEP 的浓缩系数一致。周围大气中的 TEP 浓度在云水中平均为 1 × 10 ^{3 ，}在云水中为 9 × 10 ³在环境气溶胶颗粒中，因此比罐研究中的相应富集度高出大约两个数量级。大气中超微米颗粒有机成分的这种高度富集是不常见的，我们提出大气 TEP 浓度是由海洋气泡破裂转移过程中的富集和大气相中的 TEP 原位形成相结合造成的。非生物原位形成可能来自颗粒和云水样品中存在的溶解有机前体的水反应，而生物形成涉及细菌，而细菌在云水样品中含量丰富。环境 TEP 数浓度比最近报道的在同一位置测量的冰成核粒子 (INP) 浓度高两个数量级。