Effect of simulated ocean acidification on the acute toxicity of Cu and Cd to Tigriopus japonicus@en

Heavy metals pollution in marine environments has caused great damage to marine biological and ecological systems. Heavy metals accumulate in marine creatures, after which they are delivered to higher trophic levels of marine organisms through the marine food chain, which causes serious harm to marine biological systems and human health. Additionally, excess carbon dioxide in the atmosphere has caused ocean acidification. Indeed, about one third of the CO2 released into the atmosphere by anthropogenic activities since the beginning of the industrial revolution has been absorbed by the world's oceans, which play a key role in moderating climate change. Modeling has shown that, if current trends in CO2 emissions continue, the average pH of the ocean will reach 7.8 by the end of this century, corresponding to 0.5 units below the pre-industrial level, or a three-fold increase in H+ concentration. The ocean pH has not been at this level for several millions of years. Additionally, these changes are occurring at speeds 100 times greater than ever previously observed. As a result, several marine species, communities and ecosystems might not have time to acclimate or adapt to these fast changes in ocean chemistry. In addition, decreasing ocean pH has the potential to seriously affect the growth, development and reproduction reproductive processes of marine organisms, as well as threaten normal development of the marine ecosystem. Copepods are an important part of the meiofauna that play an important role in the marine ecosystem. Pollution of the marine environment can influence their growth and development, as well as the ecological processes they are involved in. Accordingly, there is important scientific value to investigation of the response of copepods to ocean acidification and heavy metals pollution. In the present study, we evaluated the effects of simulated future ocean acidification and the toxicological interaction between ocean acidity and heavy metals of Cu and Cd on T. japonicus. To accomplish this, harpacticoids were exposed to Cu and Cd concentration gradient seawater that had been equilibrated with CO2 and air to reach pH 8.0, 7.7, 7.3 and 6.5 for 96 h. Survival was not significantly suppressed under single sea water acidification, and the final survival rates were greater than 93% in both the experimental groups and the controls. […]海洋环境中的重金属污染已对海洋生物与生态系统造成严重破坏。重金属会在海洋生物体内富集，并通过海洋食物链传递至更高营养级的海洋生物，进而对海洋生态系统及人类健康造成严重危害。此外，大气中过量的二氧化碳引发了海洋酸化：自工业革命以来，人为活动排放的二氧化碳中约有三分之一被全球海洋吸收，而海洋在调节气候变化方面发挥着关键作用。模型模拟结果显示，若当前二氧化碳排放趋势持续，到本世纪末海洋平均pH值将降至7.8，较工业化前水平降低0.5个单位，氢离子（H+）浓度则将提升至原来的3倍——这一pH水平已是数百万年来海洋未曾达到过的状态。不仅如此，这些变化的发生速度是以往观测到的100倍之多，诸多海洋物种、群落与生态系统可能来不及适应这种快速变化的海洋化学环境。此外，海洋pH值降低还可能严重影响海洋生物的生长、发育与繁殖过程，并威胁海洋生态系统的正常运转。桡足类（Copepods）是在海洋生态系统中发挥重要作用的小型底栖生物（meiofauna）的重要类群，海洋环境污染会影响其生长发育及所参与的生态过程，因此研究桡足类对海洋酸化与重金属污染的响应具有重要的科学价值。本研究评估了模拟未来海洋酸化场景，以及铜（Cu）、镉（Cd）与海洋酸度的毒理交互作用对日本猛水蚤（T. japonicus）的影响。实验中将猛水蚤类（harpacticoids）暴露于经二氧化碳与空气平衡至pH 8.0、7.7、7.3和6.5的铜、镉浓度梯度海水中，暴露时长为96小时。单一海水酸化胁迫下，生物存活率未受到显著抑制，实验组与对照组的最终存活率均高于93%。[…]