Persistence and biodegradation of oil at the ocean floor following Deepwater Horizon
Persistence and biodegradation of oil at the ocean floor following Deepwater Horizon
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DOI：
10.1073/pnas.1610110114
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发表时间：
2017-01-03
影响因子：
11.1
通讯作者：
Valentine, David L.
中科院分区：
文献类型：
--
作者：
Bagby, Sarah C.;Reddy, Christopher M.;Valentine, David L.
2010年的深水地平线灾难导致前所未有的石油排放到墨西哥湾深处。关于深海石油的命运和影响，仍然存在相当大的不确定性。在这项工作中，我们评估了125脂肪族，芳香族和生物标志物石油烃的生物降解的化合物特定速率，这些石油烃从受损的马孔多井释放后沉降到深海海底。基于一个数据集，包括测量多达168个不同的碳氢化合物分析物在2,980年内收集的沉积物样品的泄漏，我们开发了一个马孔多石油“指纹”，并保守地确定了一个子集的312个表面活性剂样品符合污染的马孔多石油。从这些样品中的125个单独的碳氢化合物的生物降解率的分析出现了三个趋势。首先，分子结构以可预测的方式调节生物降解，最简单的结构损失最快，这表明深海生物降解的进展与其他环境相似。第二，对于许多烷烃和多环芳烃而言，生物降解分两个不同的阶段进行，这与石油颗粒保持悬浮状态时的快速损失以及沉积到海底后的缓慢损失相一致。第三，任何特定样品的生物降解程度都受到碳氢化合物含量的影响，导致污染程度较高的样品中碳氢化合物的持久性大大提高。此外，在某些条件下，我们发现了大量石油生物标志物广泛降解的有力证据，特别是包括天然内标17 α（H），21 β（H）-藿烷，通常用于计算石油风化程度。
The 2010 Deepwater Horizon disaster introduced an unprecedented discharge of oil into the deep Gulf of Mexico. Considerable uncertainty has persisted regarding the oil's fate and effects in the deep ocean. In this work we assess the compound-specific rates of biodegradation for 125 aliphatic, aromatic, and biomarker petroleum hydrocarbons that settled to the deep ocean floor following release from the damaged Macondo Well. Based on a dataset comprising measurements of up to 168 distinct hydrocarbon analytes in 2,980 sediment samples collected within 4 y of the spill, we develop a Macondo oil "fingerprint" and conservatively identify a subset of 312 surficial samples consistent with contamination by Macondo oil. Three trends emerge from analysis of the biodegradation rates of 125 individual hydrocarbons in these samples. First, molecular structure served to modulate biodegradation in a predictable fashion, with the simplest structures subject to fastest loss, indicating that biodegradation in the deep ocean progresses similarly to other environments. Second, for many alkanes and polycyclic aromatic hydrocarbons biodegradation occurred in two distinct phases, consistent with rapid loss while oil particles remained suspended followed by slow loss after deposition to the seafloor. Third, the extent of biodegradation for any given sample was influenced by the hydrocarbon content, leading to substantially greater hydrocarbon persistence among the more highly contaminated samples. In addition, under some conditions we find strong evidence for extensive degradation of numerous petroleum biomarkers, notably including the native internal standard 17 alpha(H),21 beta(H)-hopane, commonly used to calculate the extent of oil weathering.