School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK; Department of Zoology, University of Cambridge, Downing St, Cambridge CB2 3EJ, UK.
Department of Life Sciences, Ben Gurion University, Beer Sheva, Israel; Interuniversity Institute for Marine Sciences, POB 469, Eilat 88103, Israel.
J Hazard Mater. 2021 Aug 15;416:126059. doi: 10.1016/j.jhazmat.2021.126059. Epub 2021 May 14.
Microplastic (MP) pollution is a key global environmental issue and laboratory exposure studies on aquatic biota are proliferating at an exponential rate. However, most research is limited to treatment-level effects, ignoring that there may be substantial within-population variation in responses to anthropogenic stressors. MP exposure experiments often reveal considerable, yet largely overlooked, inter-individual variation in particle uptake within concentration treatments. Here, we investigated to what degree treatment-level responses to MP exposure may be affected by variation in MP ingestion rates in the early life stages of a marine fish, the Gilt-head seabream, Sparus aurata. First, we tested whether MP ingestion variation is repeatable. Second, we assessed to what degree this variation may determine individual-level effects of MP exposure on fitness-related behavioural performance (i.e., escape response). We found that consistent inter-individual variation in MP ingestion was prevalent and led to differential impacts within exposure treatments. Individuals with high MP ingestion rates exhibited markedly inferior escape responses, a result that was partially concealed in treatment-level analyses. Our findings show that the measured response of populations to environmental perturbations could be confounded by variation in individual-level responses and that the explicit integration of MP ingestion variation can reveal cryptic patterns during exposure experiments.
微塑料（MP）污染是一个关键的全球环境问题，实验室对水生生物群的暴露研究呈指数级增长。然而，大多数研究仅限于处理水平的影响，忽略了在人为胁迫下，种群内部可能存在大量的反应变异。MP 暴露实验经常揭示出，在浓度处理中，个体对颗粒的吸收存在相当大的、但在很大程度上被忽视的个体间变异。在这里，我们研究了在海洋鱼类，金头鲷，Sparus aurata 的早期生活阶段，MP 暴露的处理水平反应可能在多大程度上受到 MP 摄入率变化的影响。首先，我们测试了 MP 摄入变异是否具有可重复性。其次，我们评估了这种变异在多大程度上可能决定个体水平对与健康相关的行为表现（即逃避反应）的 MP 暴露的影响。我们发现，MP 摄入的个体间存在一致的变异，这种变异导致了暴露处理内的差异影响。具有高 MP 摄入率的个体表现出明显较差的逃避反应，这一结果在处理水平分析中部分被掩盖。我们的研究结果表明，种群对环境干扰的测量反应可能受到个体水平反应变异的干扰，而明确整合 MP 摄入变异可以揭示暴露实验中的隐藏模式。
