Mesoscale eddies significantly alter open ocean environments such as those found in the subtropical gyres that cover a large fraction of the global ocean. Previous studies have explored eddy effects on biogeochemistry and microbial community composition but not on the molecular composition of particulate organic matter. This study reports the absolute concentration of 67 metabolites and relative abundances for 640 molecular features, measured using liquid chromatography-mass spectrometry (LC-MS) following both targeted and untargeted approaches. This approach allowed us to better understand how mesoscale eddies impact the metabolome of the North Pacific Subtropical Gyre during two cruises in 2017 and 2018. We find that many metabolites track biomass trends, but metabolites like isethionic acid, homarine, and trigonelline linked to eukaryotic phytoplankton were enriched at the deep chlorophyll maximum of the cyclonic features, while degradation products such as arsenobetaine were enriched in anticyclones. In every analysis, the metabolites with the strongest responses were identified using LC-MS through untargeted metabolomics approaches, highlighting that the molecules most sensitive to environmental perturbation were not among the previously characterized metabolome. By analyzing depth variability (accounting for 20-40% of metabolomic variability across ~150 meters) and the vertical displacement of isopycnal surfaces (explaining 10-20% of variability across a sea level anomaly range of 40 centimeters and a spatial distance of 300 kilometers), this analysis constrains the importance of mesoscale eddies in shaping the chemical composition of particulate matter in the largest biomes on the planet.

中文翻译：

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代谢物反映了北太平洋副热带环流中尺度涡流引入的变化


中尺度漩涡显著改变了开阔的海洋环境，例如在覆盖全球海洋很大一部分的亚热带环流中发现的环境。以前的研究探讨了涡流对生物地球化学和微生物群落组成的影响，但没有探讨对颗粒有机物分子组成的影响。本研究报告了 67 种代谢物的绝对浓度和 640 种分子特征的相对丰度，在靶向和非靶向方法之后使用液相色谱-质谱 （LC-MS） 进行测量。这种方法使我们能够更好地了解中尺度涡流在 2017 年和 2018 年的两次巡航期间如何影响北太平洋副热带环流的代谢组。我们发现许多代谢物跟踪生物量趋势，但与真核浮游植物相关的异乙酸、homarine 和 trigonelline 等代谢物在气旋特征的深叶绿素最大值处富集，而降解产物（如砷甜菜碱）在反气旋中富集。在每次分析中，使用 LC-MS 通过非靶向代谢组学方法鉴定反应最强的代谢物，突出表明对环境扰动最敏感的分子不属于先前表征的代谢组。通过分析深度变化（占 ~150 米代谢组学变化的 20-40%）和等密度表面的垂直位移（解释 40 厘米和 300 公里空间距离的海平面异常范围内 10-20% 的变化），该分析限制了中尺度涡流在塑造地球上最大生物群落中颗粒物化学成分方面的重要性。