Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven/University of Leuven , Charles Deberiotstraat 32 bus 2439, 3000 Leuven, Belgium.
National Institute of Aquatic Resources, Technical University of Denmark , Jægersborg Alle 1D, Charlottenlund 2920, Denmark.
Environ Sci Technol. 2017 Feb 21;51(4):2409-2417. doi: 10.1021/acs.est.6b04989. Epub 2017 Feb 10.
As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species' ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and low-latitude populations. By integrating these mechanisms into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies. These results highlight that a more complete life-cycle approach that incorporates the possibility of delayed interactions between contaminants and warming in a geographical context is crucial for a more realistic risk assessment in a warming world.
由于污染物在较高温度下通常毒性更大，因此预测其在全球变暖下的影响仍然是生态风险评估的一个关键挑战。如果忽略延迟效应、污染物与升温之间的协同作用以及物种分布范围内的敏感性差异，可能会导致对风险的重要低估。我们通过研究锌对高纬度和低纬度种群的优雅豆娘蜻蜓幼虫在变形前、变形期间和变形后的暴露，以及升温的影响，解决了这三个机制。通过将这些机制整合到一项单一的研究中，我们可以识别出两种新的模式。首先，在暴露期间，锌不会影响生存，但会在幼虫阶段和变形时引起轻度到中度的暴露后死亡率，并强烈降低成虫寿命。这种跨变形的严重延迟效应在高纬度动物中尤为明显，因为它们在幼虫阶段对锌几乎没有敏感性。其次，金属和升温之间众所周知的协同作用不仅在幼虫阶段表现出来，而且在变形后也表现出来，但仅在低纬度的豆娘蜻蜓中表现出来。这些结果强调，更完整的生命周期方法，在地理背景下纳入污染物和升温之间可能存在的延迟相互作用的可能性，对于在变暖的世界中进行更现实的风险评估至关重要。
