Trimethylamine (TMA) is one of the dominant volatile amines that can impact atmospheric nucleation and serve as important carbon and nitrogen sources for microbes in marine environments. Despite the significance of this climate relevant gas, the distribution, fluxes and controls of TMA remain largely unconstrained in the ocean. Here we reported the abundance of TMA in the water column, sediment and atmosphere of Northwest Pacific marginal seas, and illustrated the distribution, source and exchange fluxes across the sea-air and sediment-water interfaces. TMA in surface waters ranged from 0.3 nM to 10.1 nM (2.5 ± 2.6 nM) and decreased from inshore to offshore waters. Significant relationships were observed between TMA and chlorophyll a, suggesting the biological control of TMA production from phytoplankton. The average sea-to-air flux of TMA in the Yellow Sea and East China Sea was 0.12 μmol m−2 d−1, contributing to an annual emission of 0.7 Gg N TMA to the atmosphere, which suggested a significant relative contribution of continental shelf seas to global oceanic TMA emissions. In marine sediments, dissolved TMA in the porewater was low (2.5–22.4 nM), while the exchangeable and base-extractable pools of TMA from the solid phase were much more abundant (> 200 nmol kg−1). Surface sediment was a source of TMA in the overlying waters, and the estimated sediment-water flux was 3.5 nmol m−2 d−1. Collectively, these results shed light on the sources and sinks of TMA across the air-sea and sediment-water interfaces and highlighted the importance of coastal waters as a significant source of TMA to the atmosphere.

中文翻译：

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西北太平洋边缘海域三甲胺的分布和通量


三甲胺 （TMA） 是主要的挥发性胺之一，可影响大气成核，是海洋环境中微生物的重要碳和氮来源。尽管这种与气候相关的气体很重要，但 TMA 的分布、通量和控制在海洋中基本上仍然不受限制。在这里，我们报告了西北太平洋边缘海水柱、沉积物和大气中 TMA 的丰度，并说明了海-气和沉积物-水界面的分布、来源和交换通量。地表水中的 TMA 范围为 0.3 nM 至 10.1 nM（2.5 ± 2.6 nM），从近海水域到近海水域均有所下降。观察到 TMA 和叶绿素 a 之间存在显着关系，表明浮游植物对 TMA 的产生进行了生物控制。黄海和东海 TMA 的平均海气通量为 0.12 μmol m-2 d-1，导致每年向大气中排放 0.7 Gg N TMA，这表明大陆架海对全球海洋 TMA 排放的相对贡献显著。在海洋沉积物中，孔隙水中溶解的 TMA 较低 （2.5–22.4 nM），而来自固相的 TMA 的可交换和碱可萃取池要丰富得多 （> 200 nmol kg-1）。表层沉积物是上覆水域中 TMA 的来源，估计沉积物-水通量为 3.5 nmol m-2 d-1。总的来说，这些结果揭示了 TMA 在气-海和沉积物-水界面上的来源和汇，并强调了沿海水域作为 TMA 对大气的重要来源的重要性。