Australian Institute of Marine Science, Townsville, Queensland, 4810, Australia.
Australian Institute of Marine Science, Townsville, Queensland, 4810, Australia.
Environ Pollut. 2023 Sep 1;332:121963. doi: 10.1016/j.envpol.2023.121963. Epub 2023 Jun 5.
The risks posed by petroleum spills to coral reefs are poorly understood and quantifying acute toxicity thresholds for aromatic hydrocarbons to reef-building corals is required to assess their sensitivity relative to other taxa. In this study, we exposed Acropora millepora to toluene, naphthalene and 1-methylnaphthalene (1-MN) in a flow-through system and assessed survivorship and sublethal responses including growth, colour and the photosynthetic performance of symbionts. Median 50% lethal concentrations (LC50s) decreased over the 7-d exposure period, reaching asymptotic values of 22,921, 5,268, 1167 μg L for toluene, naphthalene and 1-MN, respectively. Corresponding toxicokinetic parameters (ε) defining the time progression of toxicity were 0.830, 0.692, and 0.256 d, respectively. Latent effects after an additional 7-d recovery in uncontaminated seawater were not observed. Effect concentrations (EC50s) for 50% growth inhibition were 1.9- to 3.6-fold lower than the LC50s for each aromatic hydrocarbon. There were no observed effects of aromatic hydrocarbon exposure on colour score (a proxy for bleaching) or photosynthetic efficiency. Acute and chronic critical target lipid body burdens (CTLBBs) of 70.3 ± 16.3 and 13.6 ± 18.4 μmol g octanol (± standard error) were calculated for survival and growth inhibition based on 7-d LC50 and EC10 values, respectively. These species-specific constants indicate adult A. millepora is more sensitive than other corals reported so far but is of average sensitivity in comparison with other aquatic taxa in the target lipid model database. These results advance our understanding of acute hazards of petroleum contaminants to key habitat-building tropical coral reef species.
石油泄漏对珊瑚礁造成的风险尚未得到充分了解，需要量化芳香烃对造礁珊瑚的急性毒性阈值，以评估其相对于其他类群的敏感性。在这项研究中，我们在流动系统中用甲苯、萘和 1-甲基萘（1-MN）处理了鹿角杯形珊瑚（Acropora millepora），并评估了存活率和亚致死反应，包括生长、颜色和共生体的光合作用性能。50%致死浓度（LC50）在 7 天暴露期内逐渐降低，甲苯、萘和 1-MN 的 LC50 分别达到 22921、5268 和 1167μg/L 的渐近值。定义毒性随时间变化的毒代动力学参数（ε）分别为 0.830、0.692 和 0.256 d。在未受污染的海水中进行额外 7 天恢复期后，未观察到潜伏效应。每种芳香烃的 50%生长抑制效应浓度（EC50）比 LC50 低 1.9 到 3.6 倍。芳香烃暴露对颜色评分（漂白的替代指标）或光合作用效率没有观察到影响。基于 7 天 LC50 和 EC10 值，分别计算出 70.3±16.3 和 13.6±18.4μmol g 辛醇（±标准误差）的急性和慢性临界目标脂质体含量（CTLBBs），用于生存和生长抑制。这些基于物种的常数表明，成年鹿角杯形珊瑚比迄今为止报告的其他珊瑚更为敏感，但与目标脂质模型数据库中的其他水生类群相比，其敏感性处于平均水平。这些结果提高了我们对石油污染物对关键热带造礁珊瑚物种的急性危害的认识。
