Following the Deepwater Horizon oil spill (DWHOS), the formation of an unexpected and extended sedimentation event of oil-associated marine snow (MOSSFA: Marine Oil Snow Sedimentation and Flocculent Accumulation) demonstrated the importance of biology on the fate of contaminants in the oceans. We used a wide range of compound-specific data (aliphatics, hopanes, steranes, triaromatic steroids, polycyclic aromatics) to chemically characterize the MOSSFA event containing abundant and multiple hydrocarbon sources (e.g., oil residues and phytoplankton). Sediment samples were collected in 2010-2011 (ERMA-NRDA programs: Environmental Response Management Application - Natural Resource Damage Assessment) and 2018 (REDIRECT project: Resuspension, Redistribution and Deposition of Deepwater Horizon recalcitrant hydrocarbons to offshore depocenter) in the northern Gulf of Mexico to assess the role of biogenic and chemical processes on the fate of oil residues in sediments. The chemical data revealed the deposition of the different hydrocarbon mixtures observed in the water column during the DWHOS (e.g., oil slicks, submerged-plumes), defining the chemical signature of MOSSFA relative to where it originated in the water column and its fate in deep-sea sediments. MOSSFA from surface waters covered 90% of the deep-sea area studied and deposited 32% of the total oil residues observed deep-sea areas after the DWHOS while MOSSFA originated at depth from the submerged plumes covered only 9% of the deep-sea area studied and was responsible for 15% of the total deposition of oil residues. In contrast, MOSSFA originated at depth from the water column covered only 1% of the deep-sea area studied (mostly in close proximity of the DWH wellhead) but was responsible for 53% of the total deposition of oil residues observed after the spill in this area. This study describes, for the first time, a multi-chemical method for the identification of biogenic and oil-derived inputs to deep-sea sediments, critical for improving our understanding of carbon inputs and storage at depth in open ocean systems.

中文翻译：

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深水地平线泄漏事件后深海沉积物中生物和石油来源的碳氢化合物的分子标记

在深水地平线漏油事件（DWHOS）之后，与石油相关的海洋积雪（MOSSFA：海洋油积雪和絮凝物积聚）的意外和长期沉降事件的形成证明了生物学对于海洋污染物命运的重要性。我们使用了广泛的化合物特定数据（脂肪族，hop烷，甾烷，三芳族类固醇，多环芳烃）来化学表征包含大量和多种烃源（例如，油渣和浮游植物）的MOSSFA事件。在2010-2011年（ERMA-NRDA计划：环境响应管理应用程序-自然资源损害评估）和2018年（REDIRECT项目：中止，墨西哥湾北部深水地平线顽固性碳氢化合物的重新分布和沉积到近海沉积中心，以评估生物过程和化学过程对沉积物中石油残留物命运的影响。化学数据揭示了在DWHOS期间在水柱中观察到的不同碳氢化合物混合物的沉积（例如浮油，沉水羽流），这定义了MOSSFA相对于其起源于水柱的位置及其深处命运的化学特征。海沉积物。在DWHOS之后，来自地表水的MOSSFA覆盖了研究的90％的深海区域，并沉积了在深海区域观察到的总油渣的32％，而MOSSFA源自深水羽流的深度仅覆盖了9％的深海区域。进行了研究，占油渣总沉积量的15％。相比之下，MOSSFA起源于水柱深度，仅覆盖了所研究的深海区域的1％（主要在DWH井口附近），但占该地区溢油后观察到的油渣总沉积量的53％。这项研究首次描述了一种多化学方法，用于识别深海沉积物的生物成因和石油来源输入，这对于增进我们对公海深处碳输入和储存的理解至关重要。