Accidental oil spills into the ocean can lead to downward transport and settling of oil onto the seafloor as part of marine snow, as seen during the Deepwater Horizon incident in 2010 in the Gulf of Mexico. The arctic and subarctic regions may favor conditions leading to this benthic oil deposition, prompting questions about the potential impacts on benthic communities. This study investigated the effects of oil-contaminated marine snow uptake on the blue mussel ( sp.). We exposed mussels for four days to 1) oil-contaminated marine snow (MOS treatment), or to 2) chemically-enhanced water-accommodated fraction (CEWAF) of oil plus unaggregated food particles (CEWAF treatment). Both oil treatments received the same nominal concentration of oil and food. Two controls were included: 1) Clean seawater plus unaggregated food (agg-free control) and 2) clean seawater plus marine snow (marine snow control). After the exposure, mussels were allowed to recover for ten days under clean, running seawater. Samples were taken right before and after the exposure period, and after the recovery phase for the following endpoints: distribution (partitioning) of oil compounds between seawater and MOS, and between seawater and mussel tissue; DNA damage (assessed via the comet assay); clearance rate; and condition index [tissue dry weight (g) divided by shell length (mm)]. Some discernable patterns were found in the partitioning of oil compounds between seawater and MOS. However, these patterns did not translate to any significant differences in the partitioning of oil compounds into mussel tissue between the two oil treatments. DNA damage did not exceed background levels (10% tail DNA or less; to be expected in healthy, viable cells) at any sampling time point, but significantly higher DNA damage was observed in CEWAF-T compared to MOS-T mussels after the recovery phase. After the exposure, a significant difference emerged in the clearance rate between the CEWAF treatment and the agg-free control, but not between the MOS treatment and the marine snow control. All mussels except those from the CEWAF treatment exhibited an increased condition index after the exposure time. Together, these results suggest that aggregates could moderate the effects of oil exposure on blue mussels, possibly by providing better, more concentrated nutrition than unaggregated food particles.

中文翻译：

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通过海洋雪吸收石油：对蓝贻贝 (Mytilus sp.) 的影响


意外的石油泄漏到海洋可能会导致石油向下输送并作为海雪的一部分沉降到海底，正如 2010 年墨西哥湾深水地平线事件中所见。北极和亚北极地区可能有利于导致海底石油沉积的条件，从而引发了关于对海底群落潜在影响的疑问。本研究调查了受石油污染的海洋雪吸收对蓝贻贝（sp.）的影响。我们将贻贝暴露于 1) 受油污染的海洋雪（MOS 处理）或 2）化学增强的水容纳部分 (CEWAF) 的油加未聚集的食物颗粒中（CEWAF 处理）四天。两种油处理均接受相同标称浓度的油和食品。包括两个对照：1）清洁海水加未聚合食物（无聚合对照）和2）清洁海水加海洋雪（海洋雪控制）。暴露后，贻贝在干净、流动的海水中恢复十天。在暴露期之前和之后以及恢复阶段之后取样，用于以下终点：海水和 MOS 之间以及海水和贻贝组织之间油类化合物的分布（分配）； DNA 损伤（通过彗星测定评估）；清除率；和状况指数[组织干重（克）除以壳长度（毫米）]。在海水和 MOS 之间的油化合物分配中发现了一些可辨别的模式。然而，这些模式并没有转化为两种油处理之间油化合物分配到贻贝组织中的任何显着差异。 在任何采样时间点，DNA 损伤均未超过背景水平（10% 尾部 DNA 或更少；在健康、存活的细胞中是预期的），但与恢复后的 MOS-T 贻贝相比，在 CEWAF-T 中观察到明显更高的 DNA 损伤阶段。暴露后，CEWAF处理和无聚集物对照之间的清除率出现显着差异，但MOS处理和海洋雪对照之间没有显着差异。除经过 CEWAF 处理的贻贝外，所有贻贝在暴露时间后均表现出状况指数增加。总之，这些结果表明，聚集体可以减轻石油暴露对蓝贻贝的影响，可能是通过提供比未聚集的食物颗粒更好、更浓缩的营养。