Department of Biosciences, University of Oslo, Oslo, Norway.
Environ Toxicol Chem. 2020 Sep;39(9):1765-1773. doi: 10.1002/etc.4804. Epub 2020 Aug 10.
Natural biotic and anthropogenic stressors can interact to alter contaminant toxicity. Energetic restrictions are potential mechanisms causing this pattern. To identify processes underlying observed effects of predation risk and copper (Cu) on delayed copepod age at maturity, we examined how these 2 stressors affect respiration rates. We tested 2 very different copepod species: the large, pelagic calanoid Calanus finmarchicus and the small, semibenthic harpacticoid Tigriopus brevicornis. Adult individuals were exposed for 12 h to the treatments: predation risk, Cu (23 µg L ), combined predation risk and Cu (23 µg L ), or control. Oxygen concentrations were monitored continuously. The 2 species differed in their responses. We found no clear effects of either stressor in C. finmarchicus. In T. brevicornis, predation risk increased respiration rates, whereas Cu alone had little impact. In contrast, combined exposure to predation risk and Cu interacted to reduce respiration rates to less than expected. We further observed an effect of sex because female-biased T. brevicornis replicates were more sensitive to both predation risk (increased respiration rates) and Cu exposure (reduced respiration rates). The present study provides further evidence that predation risk can interact with copepod responses toward Cu exposure. Interactive effects of biotic stressors ought to be considered to improve future marine environmental monitoring. Environ Toxicol Chem 2020;39:1765-1773. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
自然生物和人为压力源可以相互作用改变污染物毒性。能量限制是导致这种模式的潜在机制。为了确定捕食风险和铜 (Cu) 对延迟成熟桡足类成熟时间的观察到的影响背后的过程，我们研究了这 2 个压力源如何影响呼吸率。我们测试了 2 种非常不同的桡足类：大型、浮游的长腹剑水蚤和小型、半底栖的桡足类。成年个体在 12 h 内暴露于以下处理：捕食风险、Cu（23 µg/L）、捕食风险和 Cu 的组合（23 µg/L）或对照。连续监测氧气浓度。这 2 个物种的反应不同。我们在长腹剑水蚤中没有发现任何压力源的明显影响。在桡足类中，捕食风险增加了呼吸率，而单独的 Cu 几乎没有影响。相反，捕食风险和 Cu 的联合暴露相互作用，使呼吸率降低到低于预期的水平。我们进一步观察到性别的影响，因为偏向雌性的桡足类复制品对捕食风险（呼吸率增加）和 Cu 暴露（呼吸率降低）更为敏感。本研究进一步证明，捕食风险可以与桡足类对 Cu 暴露的反应相互作用。应该考虑生物压力源的相互作用，以改善未来的海洋环境监测。环境毒理学化学 2020；39:1765-1773。© 2020 作者。环境毒理化学由 Wiley 期刊出版公司代表 SETAC 出版。
