Recent oil spill responses such as the Deepwater Horizon event have underscored the need for crude oil ecotoxicological threshold data for shallow water corals to assist in natural resource damage assessments. We determined the toxicity of a mechanically agitated oil-seawater mixture (high-energy water-accommodated fraction, HEWAF) of a sweet crude oil on a branched stony coral, Pocillopora damicornis. We report the results of two experiments: a 96 h static renewal exposure experiment and a "pulse-chase" experiment of three short-term exposure durations followed by a recovery period in artificial seawater. Five endpoints were used to determine ecotoxicological values: 1) algal symbiont chlorophyll fluorescence, 2) a tissue regeneration assay and a visual health metric with three endpoints: 3) tissue integrity, 4) tissue color, and 5) polyp behavior. The sum of 50 entrained polycyclic aromatic hydrocarbons (tPAH50) was used as a proxy for oil exposure. For the 96 h exposure dose response experiment, dark-adapted maximum quantum yield (Fv/Fm) of the dinoflagellate symbionts was least affected by crude oil (EC50 = 913 μg/L tPAH50); light-adapted effective quantum yield (EQY) was more sensitive (EC50 =  428 μg/L tPAH50). In the health assessment, polyp behavior (EC50 = 27 μg/L tPAH50) was more sensitive than tissue integrity (EC50 = 806 μg/L tPAH50) or tissue color (EC50 = 926 μg/L tPAH50). Tissue regeneration proved to be a particularly sensitive measurement for toxicity effects (EC50 = 10 μg/L tPAH50). Short duration (6-24 h) exposures using 503 μg/L tPAH50 (average concentration) resulted in negative impacts to P. damicornis and its symbionts. Recovery of chlorophyll a fluorescence levels for 6-24 h oil exposures was observed in a few hours (Fv/Fm) to several days (EQY) following recovery in fresh seawater. The coral health assessments for tissue integrity and tissue color were not affected following short-term oil exposure durations, but the 96 h treatment duration resulted in significant decreases for both. A reduction in polyp behavior (extension) was observed for all treatment durations, with recovery observed for the short-term (6-24 h) exposures within 1-2 days following placement in fresh seawater. Wounded and intact fragments exposed to oil treatments were particularly sensitive, with significant delays observed in tissue regeneration. Estimating ecotoxicological values for P. damicornis exposed to crude oil HEWAFs provides a basis for natural resource damage assessments for oil spills in reef ecosystems. These data, when combined with ecotoxicological values for other coral reef species, will contribute to the development of species sensitivity models.

中文翻译：

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路易斯安那州甜原油对太平洋珊瑚Pocillopora damicornis的影响。

最近发生的诸如深水地平线事件等漏油事件表明，需要浅水珊瑚的原油生态毒理学阈值数据来协助评估自然资源损害。我们测定了甜原油的机械搅拌油-海水混合物（高能水含量，HEWAF）对支化石珊瑚Pocillopora damicornis的毒性。我们报告了两个实验的结果：一个96小时的静态更新暴露实验和一个“脉冲追踪”实验，其中三个短期暴露持续时间，然后是人造海水中的恢复期。五个端点用于确定生态毒理学价值：1）藻类共生叶绿素荧光，2）组织再生测定和具有三个端点的视觉健康指标：3）组织完整性，4）组织颜色，5）息肉行为。使用50个夹带的多环芳烃（tPAH50）的总和作为石油接触的代名词。对于96 h暴露剂量响应实验，原油中对鞭毛共生菌暗适应的最大量子产率（Fv / Fm）的影响最小（EC50 = 913μg/ L tPAH50）；光适应有效量子产率（EQY）更为敏感（EC50 = 428μg/ L tPAH50）。在健康评估中，息肉行为（EC50 = 27μg/ L tPAH50）比组织完整性（EC50 = 806μg/ L tPAH50）或组织颜色（EC50 = 926μg/ L tPAH50）更敏感。组织再生被证明是对毒性作用特别敏感的量度（EC50 = 10μg/ L tPAH50）。使用503μg/ L tPAH50（平均浓度）的短时间暴露（6-24小时）会对假单胞菌及其共生体产生负面影响。在淡海水中恢复后数小时（Fv / Fm）至几天（EQY），观察到暴露于油中6-24小时的叶绿素a荧光水平得以恢复。短期吸油持续时间后，珊瑚健康评估的组织完整性和组织颜色并未受到影响，但是96 h的治疗持续时间导致两者的显着减少。在所有处理期间，观察到息肉行为（延伸）的减少，放置在淡海水中后的1-2天内，短期（6-24小时）暴露可观察到恢复。暴露于油脂处理的受伤和完整的碎片特别敏感，在组织再生中观察到明显的延迟。估算P的生态毒理学价值。暴露于原油HEWAF中的大mic为珊瑚礁生态系统中溢油的自然资源破坏评估提供了基础。这些数据与其他珊瑚礁物种的生态毒理学价值相结合，将有助于建立物种敏感性模型。