Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Ecotoxicol Environ Saf. 2020 Jun 15;196:110511. doi: 10.1016/j.ecoenv.2020.110511. Epub 2020 Apr 1.
Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants in marine ecosystems including threatened and potentially sensitive coral reefs. Lower organisms such as phytoplankton, known to bioconcentrate PAHs, could serve as potential entry points for these chemicals into higher trophic levels. Here, we present a novel method using a C-labelled PAH and cavity ring-down spectroscopy (CRDS) to investigate accumulation, uptake rates and trophic transfer of PAHs in corals, which are key organisms to sustain biodiversity in tropical seas. We quantified the accumulation of C-phenanthrene in the marine microalga Dunaliella salina, and in the coral Acropora millepora after diffusive uptake from seawater or dietary uptake via labelled D. salina. Additionally, we monitored the photophysiological health of D. salina and A. millepora during phenanthrene exposure by pulse-amplitude modulation (PAM) fluorometry. Dose-dependent accumulation of C-phenanthrene in the microalga showed a mean bioconcentration factor (BCF) of 2590 ± 787 L kg dry weight. Corals accumulated phenanthrene from both exposure routes. While uptake of C-phenanthrene in corals was faster through aqueous exposure than dietary exposure, passive diffusion showed larger variability between individuals and both routes resulted in accumulation of similar concentrations of phenanthrene. The C-PAH labelling and analysis by CRDS proved to be a highly sensitive method. The use of stable isotopic label eliminated additional toxicity and risks by radioactive isotopic-labelling, and CRDS reduced the analytical complexity of PAH (less biomass, no extraction, fast analysis). The simultaneous, precise quantification of both carbon content and C/C ratio (δC) enabled accurate determination of C-phenanthrene accumulation and uptake rate. This is the first study to provide empirical evidence for accumulation of phenanthrene in a phytoplankton-coral food chain.
多环芳烃（PAHs）是海洋生态系统中广泛存在的污染物，包括受到威胁和潜在敏感的珊瑚礁。浮游植物等低级生物已知会生物浓缩 PAHs，它们可能成为这些化学物质进入更高营养级的潜在入口。在这里，我们提出了一种使用 C 标记的 PAH 和腔衰荡光谱（CRDS）的新方法，以研究 PAHs 在珊瑚中的积累、吸收速率和营养转移，珊瑚是维持热带海洋生物多样性的关键生物。我们量化了 Marine microalga Dunaliella salina 中 C-菲的积累，以及从海水中扩散吸收或通过标记的 D. salina 饮食吸收后珊瑚 Acropora millepora 中 C-菲的积累。此外，我们通过脉冲幅度调制（PAM）荧光法监测 D. salina 和 A. millepora 在菲暴露期间的光生理健康。微藻中 C-菲的剂量依赖性积累表明平均生物浓缩因子（BCF）为 2590±787 L kg 干重。珊瑚从两种暴露途径中都积累了菲。虽然通过水暴露吸收 C-菲的速度比饮食暴露快，但被动扩散在个体之间显示出更大的可变性，两种途径都导致了菲的积累浓度相似。C-PAH 标记和 CRDS 分析被证明是一种高度敏感的方法。使用稳定同位素标记消除了放射性同位素标记的额外毒性和风险，而 CRDS 降低了 PAH 的分析复杂性（较少的生物量，无需提取，快速分析）。同时精确地定量碳含量和 C/C 比（δC）能够准确确定 C-菲的积累和吸收速率。这是第一个提供菲在浮游植物-珊瑚食物链中积累的经验证据的研究。
