Sea-to-air emissions of very short-lived brominated halocarbons (VSLBrHs) are known to contribute to 30 % of stratospheric and tropospheric ozone depletion. However, empirical data on their occurrence in open ocean are scarce, which makes it difficult to estimate the significant contribution of open ocean releases to the global budget of halocarbons. This study was conducted in 2022 to explore the spatial variations of VSLBrHs and their controlling factors in the western tropical Pacific Ocean (WTPO). The findings highlighted that high biological productivity and the resulting dissolved organic matter (DOM) as well as upwelling dynamics significantly influenced the distribution and production of VSLBrHs in seawater, with atmospheric levels primarily governed by oceanic emissions. Based on the simultaneous observation of seawater and atmospheric concentrations, the mean sea-to-air fluxes of CHBr, CHBr, CHBrCl, and CHBrCl were estimated to be 1.01, 6.65, 9.31, and 7.25 nmol m d, respectively. Sea-to-air fluxes of these gases in the upwelling regions were 9.0, 4.6, 2.9, and 6.8 times those in the non-upwelling regions, respectively. Additionally, in-situ incubation experiments revealed that the enzymatic mediated biosynthesis pathways of VSLBrHs were enhanced under temperature and light-induced stress and in waters rich in humus-like substances. Therefore, we tentatively concluded that abundant photothermal conditions and the existence of upwelling in the WTPO made it a potential hotspot for the emission of VSLBrHs. This study offers critical insights into the environmental dynamics of VSLBrHs emissions and underscores the importance of regional oceanic conditions in influencing atmospheric greenhouse gas compositions.

中文翻译：

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光热条件和上升流增强了西热带太平洋中非常短暂的溴化卤化碳排放


据了解，寿命极短的溴化卤化碳 (VSLBrH) 从海到空的排放导致平流层和对流层臭氧消耗的 30%。然而，有关其在公海中发生情况的经验数据很少，这使得很难估计公海释放对全球卤代碳预算的重大贡献。本研究于2022年进行，旨在探讨热带西太平洋（WTPO）VSLBrHs的空间变化及其控制因素。研究结果强调，高生物生产力和由此产生的溶解有机物 (DOM) 以及上升流动力学显着影响海水中 VSLBrH 的分布和产生，其中大气水平主要受海洋排放控制。根据海水和大气浓度的同步观测，CHBr、CHBr、CHBrCl 和 CHBrCl 的平均海气通量估计分别为 1.01、6.65、9.31 和 7.25 nmol m·d。上升流区域这些气体的海气通量分别是非上升流区域的 9.0、4.6、2.9 和 6.8 倍。此外，原位培养实验表明，在温度和光诱导的胁迫下以及在富含腐殖质类物质的水中，酶介导的 VSLBrH 生物合成途径得到增强。因此，我们初步得出结论，WTPO丰富的光热条件和上升流的存在使其成为VSLBrHs排放的潜在热点。这项研究为 VSLBrHs 排放的环境动态提供了重要的见解，并强调了区域海洋条件在影响大气温室气体成分方面的重要性。